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linux/tools/testing/selftests/bpf/verifier/calls.c

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bpf: selftests: Add selftests for module kfunc support This adds selftests that tests the success and failure path for modules kfuncs (in presence of invalid kfunc calls) for both libbpf and gen_loader. It also adds a prog_test kfunc_btf_id_list so that we can add module BTF ID set from bpf_testmod. This also introduces a couple of test cases to verifier selftests for validating whether we get an error or not depending on if invalid kfunc call remains after elimination of unreachable instructions. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211002011757.311265-10-memxor@gmail.com
2021-10-02 06:47:57 +05:30
{
"calls: invalid kfunc call not eliminated",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = REJECT,
.errstr = "invalid kernel function call not eliminated in verifier pass",
},
{
"calls: invalid kfunc call unreachable",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_IMM(BPF_JGT, BPF_REG_0, 0, 2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
selftests/bpf: Extend kfunc selftests Use the prog_test kfuncs to test the referenced PTR_TO_BTF_ID kfunc support, and PTR_TO_CTX, PTR_TO_MEM argument passing support. Also testing the various failure cases for invalid kfunc prototypes. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220114163953.1455836-10-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-14 22:09:52 +05:30
{
"calls: invalid kfunc call: ptr_to_mem to struct with non-scalar",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type STRUCT prog_test_fail1 must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail1", 2 },
},
},
{
"calls: invalid kfunc call: ptr_to_mem to struct with nesting depth > 4",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "max struct nesting depth exceeded\narg#0 pointer type STRUCT prog_test_fail2",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail2", 2 },
},
},
{
"calls: invalid kfunc call: ptr_to_mem to struct with FAM",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type STRUCT prog_test_fail3 must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail3", 2 },
},
},
{
"calls: invalid kfunc call: reg->type != PTR_TO_CTX",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
bpf: Fix error message on kfunc arg type mismatch When "arg#%d expected pointer to ctx, but got %s" error is printed, both template parts actually point to the type of the argument, therefore, it will also say "but got PTR", regardless of what was the actual register type. Fix the message to print the register type in the second part of the template, change the existing test to adapt to the new format, and add a new test to test the case when arg is a pointer to context, but reg is a scalar. Fixes: 00b85860feb8 ("bpf: Rewrite kfunc argument handling") Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/bpf/20240909133909.1315460-1-maxim@isovalent.com
2024-09-09 16:39:09 +03:00
.errstr = "arg#0 expected pointer to ctx, but got fp",
selftests/bpf: Extend kfunc selftests Use the prog_test kfuncs to test the referenced PTR_TO_BTF_ID kfunc support, and PTR_TO_CTX, PTR_TO_MEM argument passing support. Also testing the various failure cases for invalid kfunc prototypes. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220114163953.1455836-10-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-01-14 22:09:52 +05:30
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_pass_ctx", 2 },
},
},
{
"calls: invalid kfunc call: void * not allowed in func proto without mem size arg",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type UNKNOWN must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_mem_len_fail1", 2 },
},
},
selftests/bpf: Add test for reg2btf_ids out of bounds access This test tries to pass a PTR_TO_BTF_ID_OR_NULL to the release function, which would trigger a out of bounds access without the fix in commit 45ce4b4f9009 ("bpf: Fix crash due to out of bounds access into reg2btf_ids.") but after the fix, it should only index using base_type(reg->type), which should be less than __BPF_REG_TYPE_MAX, and also not permit any type flags to be set for the reg->type. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220220023138.2224652-1-memxor@gmail.com
2022-02-20 08:01:38 +05:30
{
"calls: trigger reg2btf_ids[reg->type] for reg->type > __BPF_REG_TYPE_MAX",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS, even though they have a superset of the requirements of KF_TRUSTED_ARGS. Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require _either_ an argument with ref_obj_id > 0, _or_ (ref->type & BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't automatically imply KF_TRUSTED_ARGS, some of these requirements are enforced in different ways that can make the behavior of the verifier feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able argument will currently fail in the verifier with a message like, "arg#0 is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL pointer passed to trusted arg0". Our intention is the same, but the semantics are different due to implemenetation details that kfunc authors and BPF program writers should not need to care about. Let's make the behavior of the verifier more consistent and intuitive by having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default anyways, so this takes us a step in that direction. Note that it does not make sense to assume KF_TRUSTED_ARGS for all KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that can be left to another patch set, and there are no such subtleties to address for KF_RELEASE. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:31:46 -05:00
.errstr = "Possibly NULL pointer passed to trusted arg0",
selftests/bpf: Add test for reg2btf_ids out of bounds access This test tries to pass a PTR_TO_BTF_ID_OR_NULL to the release function, which would trigger a out of bounds access without the fix in commit 45ce4b4f9009 ("bpf: Fix crash due to out of bounds access into reg2btf_ids.") but after the fix, it should only index using base_type(reg->type), which should be less than __BPF_REG_TYPE_MAX, and also not permit any type flags to be set for the reg->type. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220220023138.2224652-1-memxor@gmail.com
2022-02-20 08:01:38 +05:30
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_release", 5 },
},
},
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
{
"calls: invalid kfunc call: reg->off must be zero when passed to release kfunc",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "R1 must have zero offset when passed to release func",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_memb_release", 8 },
},
},
selftests/bpf: Add test for strict BTF type check Ensure that the edge case where first member type was matched successfully even if it didn't match BTF type of register is caught and rejected by the verifier. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220424214901.2743946-14-memxor@gmail.com
2022-04-25 03:19:01 +05:30
{
"calls: invalid kfunc call: don't match first member type when passed to release kfunc",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "kernel function bpf_kfunc_call_memb1_release args#0 expected pointer",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_memb_acquire", 1 },
{ "bpf_kfunc_call_memb1_release", 5 },
},
},
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
{
"calls: invalid kfunc call: PTR_TO_BTF_ID with negative offset",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS, even though they have a superset of the requirements of KF_TRUSTED_ARGS. Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require _either_ an argument with ref_obj_id > 0, _or_ (ref->type & BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't automatically imply KF_TRUSTED_ARGS, some of these requirements are enforced in different ways that can make the behavior of the verifier feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able argument will currently fail in the verifier with a message like, "arg#0 is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL pointer passed to trusted arg0". Our intention is the same, but the semantics are different due to implemenetation details that kfunc authors and BPF program writers should not need to care about. Let's make the behavior of the verifier more consistent and intuitive by having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default anyways, so this takes us a step in that direction. Note that it does not make sense to assume KF_TRUSTED_ARGS for all KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that can be left to another patch set, and there are no such subtleties to address for KF_RELEASE. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:31:46 -05:00
BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -4),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS, even though they have a superset of the requirements of KF_TRUSTED_ARGS. Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require _either_ an argument with ref_obj_id > 0, _or_ (ref->type & BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't automatically imply KF_TRUSTED_ARGS, some of these requirements are enforced in different ways that can make the behavior of the verifier feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able argument will currently fail in the verifier with a message like, "arg#0 is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL pointer passed to trusted arg0". Our intention is the same, but the semantics are different due to implemenetation details that kfunc authors and BPF program writers should not need to care about. Let's make the behavior of the verifier more consistent and intuitive by having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default anyways, so this takes us a step in that direction. Note that it does not make sense to assume KF_TRUSTED_ARGS for all KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that can be left to another patch set, and there are no such subtleties to address for KF_RELEASE. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:31:46 -05:00
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS, even though they have a superset of the requirements of KF_TRUSTED_ARGS. Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require _either_ an argument with ref_obj_id > 0, _or_ (ref->type & BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE only allows for ref_obj_id > 0. Because KF_RELEASE today doesn't automatically imply KF_TRUSTED_ARGS, some of these requirements are enforced in different ways that can make the behavior of the verifier feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able argument will currently fail in the verifier with a message like, "arg#0 is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL pointer passed to trusted arg0". Our intention is the same, but the semantics are different due to implemenetation details that kfunc authors and BPF program writers should not need to care about. Let's make the behavior of the verifier more consistent and intuitive by having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default anyways, so this takes us a step in that direction. Note that it does not make sense to assume KF_TRUSTED_ARGS for all KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that can be left to another patch set, and there are no such subtleties to address for KF_RELEASE. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:31:46 -05:00
{ "bpf_kfunc_call_test_offset", 9 },
{ "bpf_kfunc_call_test_release", 12 },
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
},
.result_unpriv = REJECT,
.result = REJECT,
bpf: Refactor RCU enforcement in the verifier. bpf_rcu_read_lock/unlock() are only available in clang compiled kernels. Lack of such key mechanism makes it impossible for sleepable bpf programs to use RCU pointers. Allow bpf_rcu_read_lock/unlock() in GCC compiled kernels (though GCC doesn't support btf_type_tag yet) and allowlist certain field dereferences in important data structures like tast_struct, cgroup, socket that are used by sleepable programs either as RCU pointer or full trusted pointer (which is valid outside of RCU CS). Use BTF_TYPE_SAFE_RCU and BTF_TYPE_SAFE_TRUSTED macros for such tagging. They will be removed once GCC supports btf_type_tag. With that refactor check_ptr_to_btf_access(). Make it strict in enforcing PTR_TRUSTED and PTR_UNTRUSTED while deprecating old PTR_TO_BTF_ID without modifier flags. There is a chance that this strict enforcement might break existing programs (especially on GCC compiled kernels), but this cleanup has to start sooner than later. Note PTR_TO_CTX access still yields old deprecated PTR_TO_BTF_ID. Once it's converted to strict PTR_TRUSTED or PTR_UNTRUSTED the kfuncs and helpers will be able to default to KF_TRUSTED_ARGS. KF_RCU will remain as a weaker version of KF_TRUSTED_ARGS where obj refcnt could be 0. Adjust rcu_read_lock selftest to run on gcc and clang compiled kernels. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20230303041446.3630-7-alexei.starovoitov@gmail.com
2023-03-02 20:14:46 -08:00
.errstr = "ptr R1 off=-4 disallowed",
selftests/bpf: Add tests for kfunc register offset checks Include a few verifier selftests that test against the problems being fixed by previous commits, i.e. release kfunc always require PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not permitted and returns a helpful error message. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
2022-03-05 04:16:45 +05:30
},
{
"calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_0, 4),
BPF_JMP_IMM(BPF_JLE, BPF_REG_2, 4, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_release", 9 },
{ "bpf_kfunc_call_test_release", 13 },
{ "bpf_kfunc_call_test_release", 17 },
},
.result_unpriv = REJECT,
.result = REJECT,
.errstr = "variable ptr_ access var_off=(0x0; 0x7) disallowed",
},
selftests/bpf: Add verifier tests for trusted kfunc args Make sure verifier rejects the bad cases and ensure the good case keeps working. The selftests make use of the bpf_kfunc_call_test_ref kfunc added in the previous patch only for verification. Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220721134245.2450-11-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-21 15:42:42 +02:00
{
"calls: invalid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_ref", 8 },
{ "bpf_kfunc_call_test_ref", 10 },
},
.result_unpriv = REJECT,
.result = REJECT,
bpf: Introduce kptr_rcu. The life time of certain kernel structures like 'struct cgroup' is protected by RCU. Hence it's safe to dereference them directly from __kptr tagged pointers in bpf maps. The resulting pointer is MEM_RCU and can be passed to kfuncs that expect KF_RCU. Derefrence of other kptr-s returns PTR_UNTRUSTED. For example: struct map_value { struct cgroup __kptr *cgrp; }; SEC("tp_btf/cgroup_mkdir") int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp_arg, const char *path) { struct cgroup *cg, *cg2; cg = bpf_cgroup_acquire(cgrp_arg); // cg is PTR_TRUSTED and ref_obj_id > 0 bpf_kptr_xchg(&v->cgrp, cg); cg2 = v->cgrp; // This is new feature introduced by this patch. // cg2 is PTR_MAYBE_NULL | MEM_RCU. // When cg2 != NULL, it's a valid cgroup, but its percpu_ref could be zero if (cg2) bpf_cgroup_ancestor(cg2, level); // safe to do. } Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20230303041446.3630-4-alexei.starovoitov@gmail.com
2023-03-02 20:14:43 -08:00
.errstr = "R1 must be",
selftests/bpf: Add verifier tests for trusted kfunc args Make sure verifier rejects the bad cases and ensure the good case keeps working. The selftests make use of the bpf_kfunc_call_test_ref kfunc added in the previous patch only for verification. Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220721134245.2450-11-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-21 15:42:42 +02:00
},
{
"calls: valid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_ref", 8 },
{ "bpf_kfunc_call_test_release", 10 },
},
.result_unpriv = REJECT,
.result = ACCEPT,
},
selftests/bpf: Test for null-pointer-deref bugfix in resolve_prog_type() This test verifies that resolve_prog_type() works as expected when `attach_prog_fd` is not passed in. `prog->aux->dst_prog` in resolve_prog_type() is assigned by `attach_prog_fd`, and would be NULL if `attach_prog_fd` is not provided. Loading EXT prog with bpf_dynptr_from_skb() kfunc call in this way will lead to null-pointer-deref. Verify that the null-pointer-deref bug in resolve_prog_type() is fixed. Signed-off-by: Tengda Wu <wutengda@huaweicloud.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240711145819.254178-3-wutengda@huaweicloud.com
2024-07-11 22:58:19 +08:00
{
"calls: invalid kfunc call: must provide (attach_prog_fd, btf_id) pair when freplace",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_EXT,
.result = REJECT,
.errstr = "Tracing programs must provide btf_id",
.fixup_kfunc_btf_id = {
{ "bpf_dynptr_from_skb", 0 },
},
},
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
{
"calls: basic sanity",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
{
selftests/bpf: Fix spelling mistake "unpriviledged" -> "unprivileged" There are a couple of spelling mistakes, one in a literal string and one in a comment. Fix them. Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220928221555.67873-1-colin.i.king@gmail.com
2022-09-28 23:15:55 +01:00
"calls: not on unprivileged",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
},
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
.errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result_unpriv = REJECT,
.result = ACCEPT,
.retval = 1,
},
{
"calls: div by 0 in subprog",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 8),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV32_IMM(BPF_REG_2, 0),
BPF_MOV32_IMM(BPF_REG_3, 1),
BPF_ALU32_REG(BPF_DIV, BPF_REG_3, BPF_REG_2),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 1,
},
{
"calls: multiple ret types in subprog 1",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 8),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV32_IMM(BPF_REG_0, 42),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
bpf: Small BPF verifier log improvements In particular these include: 1) Remove output of inv for scalars in print_verifier_state 2) Replace inv with scalar in verifier error messages 3) Remove _value suffixes for umin/umax/s32_min/etc (except map_value) 4) Remove output of id=0 5) Remove output of ref_obj_id=0 Signed-off-by: Mykola Lysenko <mykolal@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220301222745.1667206-1-mykolal@fb.com
2022-03-01 14:27:45 -08:00
.errstr = "R0 invalid mem access 'scalar'",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: multiple ret types in subprog 2",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 8),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 9),
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
offsetof(struct __sk_buff, data)),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 64),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 16 },
.result = REJECT,
bpf: Implement BPF ring buffer and verifier support for it This commit adds a new MPSC ring buffer implementation into BPF ecosystem, which allows multiple CPUs to submit data to a single shared ring buffer. On the consumption side, only single consumer is assumed. Motivation ---------- There are two distinctive motivators for this work, which are not satisfied by existing perf buffer, which prompted creation of a new ring buffer implementation. - more efficient memory utilization by sharing ring buffer across CPUs; - preserving ordering of events that happen sequentially in time, even across multiple CPUs (e.g., fork/exec/exit events for a task). These two problems are independent, but perf buffer fails to satisfy both. Both are a result of a choice to have per-CPU perf ring buffer. Both can be also solved by having an MPSC implementation of ring buffer. The ordering problem could technically be solved for perf buffer with some in-kernel counting, but given the first one requires an MPSC buffer, the same solution would solve the second problem automatically. Semantics and APIs ------------------ Single ring buffer is presented to BPF programs as an instance of BPF map of type BPF_MAP_TYPE_RINGBUF. Two other alternatives considered, but ultimately rejected. One way would be to, similar to BPF_MAP_TYPE_PERF_EVENT_ARRAY, make BPF_MAP_TYPE_RINGBUF could represent an array of ring buffers, but not enforce "same CPU only" rule. This would be more familiar interface compatible with existing perf buffer use in BPF, but would fail if application needed more advanced logic to lookup ring buffer by arbitrary key. HASH_OF_MAPS addresses this with current approach. Additionally, given the performance of BPF ringbuf, many use cases would just opt into a simple single ring buffer shared among all CPUs, for which current approach would be an overkill. Another approach could introduce a new concept, alongside BPF map, to represent generic "container" object, which doesn't necessarily have key/value interface with lookup/update/delete operations. This approach would add a lot of extra infrastructure that has to be built for observability and verifier support. It would also add another concept that BPF developers would have to familiarize themselves with, new syntax in libbpf, etc. But then would really provide no additional benefits over the approach of using a map. BPF_MAP_TYPE_RINGBUF doesn't support lookup/update/delete operations, but so doesn't few other map types (e.g., queue and stack; array doesn't support delete, etc). The approach chosen has an advantage of re-using existing BPF map infrastructure (introspection APIs in kernel, libbpf support, etc), being familiar concept (no need to teach users a new type of object in BPF program), and utilizing existing tooling (bpftool). For common scenario of using a single ring buffer for all CPUs, it's as simple and straightforward, as would be with a dedicated "container" object. On the other hand, by being a map, it can be combined with ARRAY_OF_MAPS and HASH_OF_MAPS map-in-maps to implement a wide variety of topologies, from one ring buffer for each CPU (e.g., as a replacement for perf buffer use cases), to a complicated application hashing/sharding of ring buffers (e.g., having a small pool of ring buffers with hashed task's tgid being a look up key to preserve order, but reduce contention). Key and value sizes are enforced to be zero. max_entries is used to specify the size of ring buffer and has to be a power of 2 value. There are a bunch of similarities between perf buffer (BPF_MAP_TYPE_PERF_EVENT_ARRAY) and new BPF ring buffer semantics: - variable-length records; - if there is no more space left in ring buffer, reservation fails, no blocking; - memory-mappable data area for user-space applications for ease of consumption and high performance; - epoll notifications for new incoming data; - but still the ability to do busy polling for new data to achieve the lowest latency, if necessary. BPF ringbuf provides two sets of APIs to BPF programs: - bpf_ringbuf_output() allows to *copy* data from one place to a ring buffer, similarly to bpf_perf_event_output(); - bpf_ringbuf_reserve()/bpf_ringbuf_commit()/bpf_ringbuf_discard() APIs split the whole process into two steps. First, a fixed amount of space is reserved. If successful, a pointer to a data inside ring buffer data area is returned, which BPF programs can use similarly to a data inside array/hash maps. Once ready, this piece of memory is either committed or discarded. Discard is similar to commit, but makes consumer ignore the record. bpf_ringbuf_output() has disadvantage of incurring extra memory copy, because record has to be prepared in some other place first. But it allows to submit records of the length that's not known to verifier beforehand. It also closely matches bpf_perf_event_output(), so will simplify migration significantly. bpf_ringbuf_reserve() avoids the extra copy of memory by providing a memory pointer directly to ring buffer memory. In a lot of cases records are larger than BPF stack space allows, so many programs have use extra per-CPU array as a temporary heap for preparing sample. bpf_ringbuf_reserve() avoid this needs completely. But in exchange, it only allows a known constant size of memory to be reserved, such that verifier can verify that BPF program can't access memory outside its reserved record space. bpf_ringbuf_output(), while slightly slower due to extra memory copy, covers some use cases that are not suitable for bpf_ringbuf_reserve(). The difference between commit and discard is very small. Discard just marks a record as discarded, and such records are supposed to be ignored by consumer code. Discard is useful for some advanced use-cases, such as ensuring all-or-nothing multi-record submission, or emulating temporary malloc()/free() within single BPF program invocation. Each reserved record is tracked by verifier through existing reference-tracking logic, similar to socket ref-tracking. It is thus impossible to reserve a record, but forget to submit (or discard) it. bpf_ringbuf_query() helper allows to query various properties of ring buffer. Currently 4 are supported: - BPF_RB_AVAIL_DATA returns amount of unconsumed data in ring buffer; - BPF_RB_RING_SIZE returns the size of ring buffer; - BPF_RB_CONS_POS/BPF_RB_PROD_POS returns current logical possition of consumer/producer, respectively. Returned values are momentarily snapshots of ring buffer state and could be off by the time helper returns, so this should be used only for debugging/reporting reasons or for implementing various heuristics, that take into account highly-changeable nature of some of those characteristics. One such heuristic might involve more fine-grained control over poll/epoll notifications about new data availability in ring buffer. Together with BPF_RB_NO_WAKEUP/BPF_RB_FORCE_WAKEUP flags for output/commit/discard helpers, it allows BPF program a high degree of control and, e.g., more efficient batched notifications. Default self-balancing strategy, though, should be adequate for most applications and will work reliable and efficiently already. Design and implementation ------------------------- This reserve/commit schema allows a natural way for multiple producers, either on different CPUs or even on the same CPU/in the same BPF program, to reserve independent records and work with them without blocking other producers. This means that if BPF program was interruped by another BPF program sharing the same ring buffer, they will both get a record reserved (provided there is enough space left) and can work with it and submit it independently. This applies to NMI context as well, except that due to using a spinlock during reservation, in NMI context, bpf_ringbuf_reserve() might fail to get a lock, in which case reservation will fail even if ring buffer is not full. The ring buffer itself internally is implemented as a power-of-2 sized circular buffer, with two logical and ever-increasing counters (which might wrap around on 32-bit architectures, that's not a problem): - consumer counter shows up to which logical position consumer consumed the data; - producer counter denotes amount of data reserved by all producers. Each time a record is reserved, producer that "owns" the record will successfully advance producer counter. At that point, data is still not yet ready to be consumed, though. Each record has 8 byte header, which contains the length of reserved record, as well as two extra bits: busy bit to denote that record is still being worked on, and discard bit, which might be set at commit time if record is discarded. In the latter case, consumer is supposed to skip the record and move on to the next one. Record header also encodes record's relative offset from the beginning of ring buffer data area (in pages). This allows bpf_ringbuf_commit()/bpf_ringbuf_discard() to accept only the pointer to the record itself, without requiring also the pointer to ring buffer itself. Ring buffer memory location will be restored from record metadata header. This significantly simplifies verifier, as well as improving API usability. Producer counter increments are serialized under spinlock, so there is a strict ordering between reservations. Commits, on the other hand, are completely lockless and independent. All records become available to consumer in the order of reservations, but only after all previous records where already committed. It is thus possible for slow producers to temporarily hold off submitted records, that were reserved later. Reservation/commit/consumer protocol is verified by litmus tests in Documentation/litmus-test/bpf-rb. One interesting implementation bit, that significantly simplifies (and thus speeds up as well) implementation of both producers and consumers is how data area is mapped twice contiguously back-to-back in the virtual memory. This allows to not take any special measures for samples that have to wrap around at the end of the circular buffer data area, because the next page after the last data page would be first data page again, and thus the sample will still appear completely contiguous in virtual memory. See comment and a simple ASCII diagram showing this visually in bpf_ringbuf_area_alloc(). Another feature that distinguishes BPF ringbuf from perf ring buffer is a self-pacing notifications of new data being availability. bpf_ringbuf_commit() implementation will send a notification of new record being available after commit only if consumer has already caught up right up to the record being committed. If not, consumer still has to catch up and thus will see new data anyways without needing an extra poll notification. Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c) show that this allows to achieve a very high throughput without having to resort to tricks like "notify only every Nth sample", which are necessary with perf buffer. For extreme cases, when BPF program wants more manual control of notifications, commit/discard/output helpers accept BPF_RB_NO_WAKEUP and BPF_RB_FORCE_WAKEUP flags, which give full control over notifications of data availability, but require extra caution and diligence in using this API. Comparison to alternatives -------------------------- Before considering implementing BPF ring buffer from scratch existing alternatives in kernel were evaluated, but didn't seem to meet the needs. They largely fell into few categores: - per-CPU buffers (perf, ftrace, etc), which don't satisfy two motivations outlined above (ordering and memory consumption); - linked list-based implementations; while some were multi-producer designs, consuming these from user-space would be very complicated and most probably not performant; memory-mapping contiguous piece of memory is simpler and more performant for user-space consumers; - io_uring is SPSC, but also requires fixed-sized elements. Naively turning SPSC queue into MPSC w/ lock would have subpar performance compared to locked reserve + lockless commit, as with BPF ring buffer. Fixed sized elements would be too limiting for BPF programs, given existing BPF programs heavily rely on variable-sized perf buffer already; - specialized implementations (like a new printk ring buffer, [0]) with lots of printk-specific limitations and implications, that didn't seem to fit well for intended use with BPF programs. [0] https://lwn.net/Articles/779550/ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200529075424.3139988-2-andriin@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-05-29 00:54:20 -07:00
.errstr = "R0 min value is outside of the allowed memory range",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: overlapping caller/callee",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "last insn is not an exit or jmp",
.result = REJECT,
},
{
"calls: wrong recursive calls",
.insns = {
BPF_JMP_IMM(BPF_JA, 0, 0, 4),
BPF_JMP_IMM(BPF_JA, 0, 0, 4),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "jump out of range",
.result = REJECT,
},
{
"calls: wrong src reg",
.insns = {
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 3, 0, 0),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "BPF_CALL uses reserved fields",
.result = REJECT,
},
{
"calls: wrong off value",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, -1, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "BPF_CALL uses reserved fields",
.result = REJECT,
},
{
"calls: jump back loop",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -1),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
bpf: fix control-flow graph checking in privileged mode When BPF program is verified in privileged mode, BPF verifier allows bounded loops. This means that from CFG point of view there are definitely some back-edges. Original commit adjusted check_cfg() logic to not detect back-edges in control flow graph if they are resulting from conditional jumps, which the idea that subsequent full BPF verification process will determine whether such loops are bounded or not, and either accept or reject the BPF program. At least that's my reading of the intent. Unfortunately, the implementation of this idea doesn't work correctly in all possible situations. Conditional jump might not result in immediate back-edge, but just a few unconditional instructions later we can arrive at back-edge. In such situations check_cfg() would reject BPF program even in privileged mode, despite it might be bounded loop. Next patch adds one simple program demonstrating such scenario. To keep things simple, instead of trying to detect back edges in privileged mode, just assume every back edge is valid and let subsequent BPF verification prove or reject bounded loops. Note a few test changes. For unknown reason, we have a few tests that are specified to detect a back-edge in a privileged mode, but looking at their code it seems like the right outcome is passing check_cfg() and letting subsequent verification to make a decision about bounded or not bounded looping. Bounded recursion case is also interesting. The example should pass, as recursion is limited to just a few levels and so we never reach maximum number of nested frames and never exhaust maximum stack depth. But the way that max stack depth logic works today it falsely detects this as exceeding max nested frame count. This patch series doesn't attempt to fix this orthogonal problem, so we just adjust expected verifier failure. Suggested-by: Alexei Starovoitov <ast@kernel.org> Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231110061412.2995786-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-09 22:14:10 -08:00
.errstr = "the call stack of 9 frames is too deep",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result = REJECT,
},
{
"calls: conditional call",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "jump out of range",
.result = REJECT,
},
{
"calls: conditional call 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
{
"calls: conditional call 3",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_JMP_IMM(BPF_JA, 0, 0, 4),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, -6),
BPF_MOV64_IMM(BPF_REG_0, 3),
BPF_JMP_IMM(BPF_JA, 0, 0, -6),
},
selftests/bpf: fix tests Fix tests that assumed no loops. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 12:12:22 -07:00
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
.errstr_unpriv = "back-edge from insn",
.result_unpriv = REJECT,
.result = ACCEPT,
.retval = 1,
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: conditional call 4",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, -5),
BPF_MOV64_IMM(BPF_REG_0, 3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
{
"calls: conditional call 5",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, -6),
BPF_MOV64_IMM(BPF_REG_0, 3),
BPF_EXIT_INSN(),
},
selftests/bpf: fix tests Fix tests that assumed no loops. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 12:12:22 -07:00
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 1,
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: conditional call 6",
.insns = {
selftests/bpf: fix tests Fix tests that assumed no loops. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 12:12:22 -07:00
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
selftests/bpf: fix tests Fix tests that assumed no loops. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 12:12:22 -07:00
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -3),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, mark)),
BPF_EXIT_INSN(),
},
selftests/bpf: fix tests Fix tests that assumed no loops. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-15 12:12:22 -07:00
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "infinite loop detected",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result = REJECT,
},
{
"calls: using r0 returned by callee",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 2),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
{
"calls: using uninit r0 from callee",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "!read_ok",
.result = REJECT,
},
{
"calls: callee is using r1",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, len)),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_ACT,
.result = ACCEPT,
.retval = TEST_DATA_LEN,
},
{
"calls: callee using args1",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
BPF_EXIT_INSN(),
},
selftests/bpf: Use CAP_BPF and CAP_PERFMON in tests Make all test_verifier test exercise CAP_BPF and CAP_PERFMON Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200513230355.7858-4-alexei.starovoitov@gmail.com
2020-05-13 16:03:55 -07:00
.errstr_unpriv = "allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result_unpriv = REJECT,
.result = ACCEPT,
.retval = POINTER_VALUE,
},
{
"calls: callee using wrong args2",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "R2 !read_ok",
.result = REJECT,
},
{
"calls: callee using two args",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
offsetof(struct __sk_buff, len)),
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_6,
offsetof(struct __sk_buff, len)),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_2),
BPF_EXIT_INSN(),
},
selftests/bpf: Use CAP_BPF and CAP_PERFMON in tests Make all test_verifier test exercise CAP_BPF and CAP_PERFMON Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200513230355.7858-4-alexei.starovoitov@gmail.com
2020-05-13 16:03:55 -07:00
.errstr_unpriv = "allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result_unpriv = REJECT,
.result = ACCEPT,
.retval = TEST_DATA_LEN + TEST_DATA_LEN - ETH_HLEN - ETH_HLEN,
},
{
"calls: callee changing pkt pointers",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_8, BPF_REG_6),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_8, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_8, BPF_REG_7, 2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
/* clear_all_pkt_pointers() has to walk all frames
* to make sure that pkt pointers in the caller
* are cleared when callee is calling a helper that
* adjusts packet size
*/
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_6, 0),
BPF_MOV32_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_xdp_adjust_head),
BPF_EXIT_INSN(),
},
.result = REJECT,
bpf: Small BPF verifier log improvements In particular these include: 1) Remove output of inv for scalars in print_verifier_state 2) Replace inv with scalar in verifier error messages 3) Remove _value suffixes for umin/umax/s32_min/etc (except map_value) 4) Remove output of id=0 5) Remove output of ref_obj_id=0 Signed-off-by: Mykola Lysenko <mykolal@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220301222745.1667206-1-mykolal@fb.com
2022-03-01 14:27:45 -08:00
.errstr = "R6 invalid mem access 'scalar'",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
selftests/bpf: test cases for pkt/null checks in subprogs The first test case, for pointer null checks, is equivalent to the following pseudo-code. It checks that the verifier does not complain on line 6 and recognizes that ptr isn't null. 1: ptr = bpf_map_lookup_elem(map, &key); 2: ret = subprog(ptr) { 3: return ptr != NULL; 4: } 5: if (ret) 6: value = *ptr; The second test case, for packet bound checks, is equivalent to the following pseudo-code. It checks that the verifier does not complain on line 7 and recognizes that the packet is at least 1 byte long. 1: pkt_end = ctx.pkt_end; 2: ptr = ctx.pkt + 8; 3: ret = subprog(ptr, pkt_end) { 4: return ptr <= pkt_end; 5: } 6: if (ret) 7: value = *(u8 *)ctx.pkt; Signed-off-by: Paul Chaignon <paul.chaignon@orange.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-24 21:51:26 +02:00
{
"calls: ptr null check in subprog",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_6, 0),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
.errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for",
selftests/bpf: test cases for pkt/null checks in subprogs The first test case, for pointer null checks, is equivalent to the following pseudo-code. It checks that the verifier does not complain on line 6 and recognizes that ptr isn't null. 1: ptr = bpf_map_lookup_elem(map, &key); 2: ret = subprog(ptr) { 3: return ptr != NULL; 4: } 5: if (ret) 6: value = *ptr; The second test case, for packet bound checks, is equivalent to the following pseudo-code. It checks that the verifier does not complain on line 7 and recognizes that the packet is at least 1 byte long. 1: pkt_end = ctx.pkt_end; 2: ptr = ctx.pkt + 8; 3: ret = subprog(ptr, pkt_end) { 4: return ptr <= pkt_end; 5: } 6: if (ret) 7: value = *(u8 *)ctx.pkt; Signed-off-by: Paul Chaignon <paul.chaignon@orange.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-24 21:51:26 +02:00
.fixup_map_hash_48b = { 3 },
.result_unpriv = REJECT,
.result = ACCEPT,
.retval = 0,
},
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
{
"calls: two calls with args",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 6),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_ALU64_REG(BPF_ADD, BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, len)),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = TEST_DATA_LEN + TEST_DATA_LEN,
},
{
"calls: calls with stack arith",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -64),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -64),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -64),
BPF_MOV64_IMM(BPF_REG_0, 42),
BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 42,
},
{
"calls: calls with misaligned stack access",
.insns = {
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -63),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -61),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -63),
BPF_MOV64_IMM(BPF_REG_0, 42),
BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.flags = F_LOAD_WITH_STRICT_ALIGNMENT,
.errstr = "misaligned stack access",
.result = REJECT,
},
{
"calls: calls control flow, jump test",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 42),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 43),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, -3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 43,
},
{
"calls: calls control flow, jump test 2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 42),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 43),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "jump out of range from insn 1 to 4",
.result = REJECT,
},
{
"calls: two calls with bad jump",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 6),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_ALU64_REG(BPF_ADD, BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, len)),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "jump out of range from insn 11 to 9",
.result = REJECT,
},
{
"calls: recursive call. test1",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -1),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
bpf: fix control-flow graph checking in privileged mode When BPF program is verified in privileged mode, BPF verifier allows bounded loops. This means that from CFG point of view there are definitely some back-edges. Original commit adjusted check_cfg() logic to not detect back-edges in control flow graph if they are resulting from conditional jumps, which the idea that subsequent full BPF verification process will determine whether such loops are bounded or not, and either accept or reject the BPF program. At least that's my reading of the intent. Unfortunately, the implementation of this idea doesn't work correctly in all possible situations. Conditional jump might not result in immediate back-edge, but just a few unconditional instructions later we can arrive at back-edge. In such situations check_cfg() would reject BPF program even in privileged mode, despite it might be bounded loop. Next patch adds one simple program demonstrating such scenario. To keep things simple, instead of trying to detect back edges in privileged mode, just assume every back edge is valid and let subsequent BPF verification prove or reject bounded loops. Note a few test changes. For unknown reason, we have a few tests that are specified to detect a back-edge in a privileged mode, but looking at their code it seems like the right outcome is passing check_cfg() and letting subsequent verification to make a decision about bounded or not bounded looping. Bounded recursion case is also interesting. The example should pass, as recursion is limited to just a few levels and so we never reach maximum number of nested frames and never exhaust maximum stack depth. But the way that max stack depth logic works today it falsely detects this as exceeding max nested frame count. This patch series doesn't attempt to fix this orthogonal problem, so we just adjust expected verifier failure. Suggested-by: Alexei Starovoitov <ast@kernel.org> Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231110061412.2995786-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-09 22:14:10 -08:00
.errstr = "the call stack of 9 frames is too deep",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result = REJECT,
},
{
"calls: recursive call. test2",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
bpf: fix control-flow graph checking in privileged mode When BPF program is verified in privileged mode, BPF verifier allows bounded loops. This means that from CFG point of view there are definitely some back-edges. Original commit adjusted check_cfg() logic to not detect back-edges in control flow graph if they are resulting from conditional jumps, which the idea that subsequent full BPF verification process will determine whether such loops are bounded or not, and either accept or reject the BPF program. At least that's my reading of the intent. Unfortunately, the implementation of this idea doesn't work correctly in all possible situations. Conditional jump might not result in immediate back-edge, but just a few unconditional instructions later we can arrive at back-edge. In such situations check_cfg() would reject BPF program even in privileged mode, despite it might be bounded loop. Next patch adds one simple program demonstrating such scenario. To keep things simple, instead of trying to detect back edges in privileged mode, just assume every back edge is valid and let subsequent BPF verification prove or reject bounded loops. Note a few test changes. For unknown reason, we have a few tests that are specified to detect a back-edge in a privileged mode, but looking at their code it seems like the right outcome is passing check_cfg() and letting subsequent verification to make a decision about bounded or not bounded looping. Bounded recursion case is also interesting. The example should pass, as recursion is limited to just a few levels and so we never reach maximum number of nested frames and never exhaust maximum stack depth. But the way that max stack depth logic works today it falsely detects this as exceeding max nested frame count. This patch series doesn't attempt to fix this orthogonal problem, so we just adjust expected verifier failure. Suggested-by: Alexei Starovoitov <ast@kernel.org> Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231110061412.2995786-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-09 22:14:10 -08:00
.errstr = "the call stack of 9 frames is too deep",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result = REJECT,
},
{
"calls: unreachable code",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "unreachable insn 6",
.result = REJECT,
},
{
"calls: invalid call",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -4),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "invalid destination",
.result = REJECT,
},
{
"calls: invalid call 2",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 0x7fffffff),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "invalid destination",
.result = REJECT,
},
{
"calls: jumping across function bodies. test1",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, -3),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "jump out of range",
.result = REJECT,
},
{
"calls: jumping across function bodies. test2",
.insns = {
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "jump out of range",
.result = REJECT,
},
{
"calls: call without exit",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, -2),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "not an exit",
.result = REJECT,
},
{
"calls: call into middle of ld_imm64",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LD_IMM64(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "last insn",
.result = REJECT,
},
{
"calls: call into middle of other call",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "last insn",
.result = REJECT,
},
{
bpf: Add abnormal return checks. LD_[ABS|IND] instructions may return from the function early. bpf_tail_call pseudo instruction is either fallthrough or return. Allow them in the subprograms only when subprograms are BTF annotated and have scalar return types. Allow ld_abs and tail_call in the main program even if it calls into subprograms. In the past that was not ok to do for ld_abs, since it was JITed with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs looks like normal exit insn from JIT point of view, so it's safe to allow them in the main program. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-09-17 19:09:18 -07:00
"calls: subprog call with ld_abs in main prog",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_LD_ABS(BPF_B, 0),
BPF_LD_ABS(BPF_H, 0),
BPF_LD_ABS(BPF_W, 0),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_6),
bpf: Add abnormal return checks. LD_[ABS|IND] instructions may return from the function early. bpf_tail_call pseudo instruction is either fallthrough or return. Allow them in the subprograms only when subprograms are BTF annotated and have scalar return types. Allow ld_abs and tail_call in the main program even if it calls into subprograms. In the past that was not ok to do for ld_abs, since it was JITed with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs looks like normal exit insn from JIT point of view, so it's safe to allow them in the main program. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-09-17 19:09:18 -07:00
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_7),
BPF_LD_ABS(BPF_B, 0),
BPF_LD_ABS(BPF_H, 0),
BPF_LD_ABS(BPF_W, 0),
BPF_EXIT_INSN(),
BPF_MOV64_IMM(BPF_REG_2, 1),
BPF_MOV64_IMM(BPF_REG_3, 2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_skb_vlan_push),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
bpf: Add abnormal return checks. LD_[ABS|IND] instructions may return from the function early. bpf_tail_call pseudo instruction is either fallthrough or return. Allow them in the subprograms only when subprograms are BTF annotated and have scalar return types. Allow ld_abs and tail_call in the main program even if it calls into subprograms. In the past that was not ok to do for ld_abs, since it was JITed with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs looks like normal exit insn from JIT point of view, so it's safe to allow them in the main program. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-09-17 19:09:18 -07:00
.result = ACCEPT,
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: two calls with bad fallthrough",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 6),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_ALU64_REG(BPF_ADD, BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, len)),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.errstr = "not an exit",
.result = REJECT,
},
{
"calls: two calls with stack read",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 6),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_ALU64_REG(BPF_ADD, BPF_REG_7, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_7),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.result = ACCEPT,
},
{
"calls: two calls with stack write",
.insns = {
/* main prog */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -16),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 7),
BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_ALU64_REG(BPF_ADD, BPF_REG_8, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_8),
/* write into stack frame of main prog */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 2 */
/* read from stack frame of main prog */
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.result = ACCEPT,
},
{
"calls: stack overflow using two frames (pre-call access)",
.insns = {
/* prog 1 */
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* prog 2 */
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "combined stack size",
.result = REJECT,
},
{
"calls: stack overflow using two frames (post-call access)",
.insns = {
/* prog 1 */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 2),
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_EXIT_INSN(),
/* prog 2 */
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "combined stack size",
.result = REJECT,
},
{
"calls: stack depth check using three frames. test1",
.insns = {
/* main */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 5), /* call B */
BPF_ST_MEM(BPF_B, BPF_REG_10, -32, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* A */
BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
BPF_EXIT_INSN(),
/* B */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -3), /* call A */
BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
/* stack_main=32, stack_A=256, stack_B=64
* and max(main+A, main+A+B) < 512
*/
.result = ACCEPT,
},
{
"calls: stack depth check using three frames. test2",
.insns = {
/* main */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 5), /* call B */
BPF_ST_MEM(BPF_B, BPF_REG_10, -32, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* A */
BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
BPF_EXIT_INSN(),
/* B */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -3), /* call A */
BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
/* stack_main=32, stack_A=64, stack_B=256
* and max(main+A, main+A+B) < 512
*/
.result = ACCEPT,
},
{
"calls: stack depth check using three frames. test3",
.insns = {
/* main */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 6), /* call A */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 8), /* call B */
BPF_JMP_IMM(BPF_JGE, BPF_REG_6, 0, 1),
BPF_ST_MEM(BPF_B, BPF_REG_10, -64, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* A */
BPF_JMP_IMM(BPF_JLT, BPF_REG_1, 10, 1),
BPF_EXIT_INSN(),
BPF_ST_MEM(BPF_B, BPF_REG_10, -224, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, -3),
/* B */
BPF_JMP_IMM(BPF_JGT, BPF_REG_1, 2, 1),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, -6), /* call A */
BPF_ST_MEM(BPF_B, BPF_REG_10, -256, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
/* stack_main=64, stack_A=224, stack_B=256
* and max(main+A, main+A+B) > 512
*/
.errstr = "combined stack",
.result = REJECT,
},
{
"calls: stack depth check using three frames. test4",
/* void main(void) {
* func1(0);
* func1(1);
* func2(1);
* }
* void func1(int alloc_or_recurse) {
* if (alloc_or_recurse) {
* frame_pointer[-300] = 1;
* } else {
* func2(alloc_or_recurse);
* }
* }
* void func2(int alloc_or_recurse) {
* if (alloc_or_recurse) {
* frame_pointer[-300] = 1;
* }
* }
*/
.insns = {
/* main */
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 6), /* call A */
BPF_MOV64_IMM(BPF_REG_1, 1),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 4), /* call A */
BPF_MOV64_IMM(BPF_REG_1, 1),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 7), /* call B */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* A */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 2),
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_EXIT_INSN(),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call B */
BPF_EXIT_INSN(),
/* B */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
BPF_ST_MEM(BPF_B, BPF_REG_10, -300, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.result = REJECT,
.errstr = "combined stack",
},
{
"calls: stack depth check using three frames. test5",
.insns = {
/* main */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call A */
BPF_EXIT_INSN(),
/* A */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call B */
BPF_EXIT_INSN(),
/* B */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call C */
BPF_EXIT_INSN(),
/* C */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call D */
BPF_EXIT_INSN(),
/* D */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call E */
BPF_EXIT_INSN(),
/* E */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call F */
BPF_EXIT_INSN(),
/* F */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call G */
BPF_EXIT_INSN(),
/* G */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call H */
BPF_EXIT_INSN(),
/* H */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "call stack",
.result = REJECT,
},
selftests/bpf: test case for invalid call stack in dead code This patch adds a test case with an excessive number of call stack frames in dead code. Signed-off-by: Paul Chaignon <paul.chaignon@orange.com> Tested-by: Xiao Han <xiao.han@orange.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-20 13:58:50 +01:00
{
"calls: stack depth check in dead code",
.insns = {
/* main */
BPF_MOV64_IMM(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call A */
BPF_EXIT_INSN(),
/* A */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 2), /* call B */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* B */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call C */
BPF_EXIT_INSN(),
/* C */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call D */
BPF_EXIT_INSN(),
/* D */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call E */
BPF_EXIT_INSN(),
/* E */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call F */
BPF_EXIT_INSN(),
/* F */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call G */
BPF_EXIT_INSN(),
/* G */
BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call H */
BPF_EXIT_INSN(),
/* H */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "call stack",
.result = REJECT,
},
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
{
"calls: spill into caller stack frame",
.insns = {
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "cannot spill",
.result = REJECT,
},
{
"calls: write into caller stack frame",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_6, 0),
BPF_EXIT_INSN(),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.result = ACCEPT,
.retval = 42,
},
{
"calls: write into callee stack frame",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 42),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, -8),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_XDP,
.errstr = "cannot return stack pointer",
.result = REJECT,
},
{
"calls: two calls with stack write and void return",
.insns = {
/* main prog */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -16),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* subprog 2 */
/* write into stack frame of main prog */
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_EXIT_INSN(), /* void return */
},
.prog_type = BPF_PROG_TYPE_XDP,
.result = ACCEPT,
},
{
"calls: ambiguous return value",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
selftests/bpf: Use CAP_BPF and CAP_PERFMON in tests Make all test_verifier test exercise CAP_BPF and CAP_PERFMON Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200513230355.7858-4-alexei.starovoitov@gmail.com
2020-05-13 16:03:55 -07:00
.errstr_unpriv = "allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result_unpriv = REJECT,
.errstr = "R0 !read_ok",
.result = REJECT,
},
{
"calls: two calls that return map_value",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 8),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* fetch secound map_value_ptr from the stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -16),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
/* call 3rd function twice */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* first time with fp-8 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
/* second time with fp-16 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* subprog 2 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr into stack frame of main prog */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(), /* return 0 */
},
.prog_type = BPF_PROG_TYPE_XDP,
.fixup_map_hash_8b = { 23 },
.result = ACCEPT,
},
{
"calls: two calls that return map_value with bool condition",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
/* call 3rd function twice */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* first time with fp-8 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 9),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_6, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
/* second time with fp-16 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 1, 2),
/* fetch secound map_value_ptr from the stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_7, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
/* subprog 2 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(), /* return 0 */
/* write map_value_ptr into stack frame of main prog */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(), /* return 1 */
},
.prog_type = BPF_PROG_TYPE_XDP,
.fixup_map_hash_8b = { 23 },
.result = ACCEPT,
},
{
"calls: two calls that return map_value with incorrect bool check",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
/* call 3rd function twice */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* first time with fp-8 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 9),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_6, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
/* second time with fp-16 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
/* fetch secound map_value_ptr from the stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_7, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
/* subprog 2 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
/* lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(), /* return 0 */
/* write map_value_ptr into stack frame of main prog */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(), /* return 1 */
},
.prog_type = BPF_PROG_TYPE_XDP,
.fixup_map_hash_8b = { 23 },
.result = REJECT,
bpf: Fix accesses to uninit stack slots Privileged programs are supposed to be able to read uninitialized stack memory (ever since 6715df8d5) but, before this patch, these accesses were permitted inconsistently. In particular, accesses were permitted above state->allocated_stack, but not below it. In other words, if the stack was already "large enough", the access was permitted, but otherwise the access was rejected instead of being allowed to "grow the stack". This undesired rejection was happening in two places: - in check_stack_slot_within_bounds() - in check_stack_range_initialized() This patch arranges for these accesses to be permitted. A bunch of tests that were relying on the old rejection had to change; all of them were changed to add also run unprivileged, in which case the old behavior persists. One tests couldn't be updated - global_func16 - because it can't run unprivileged for other reasons. This patch also fixes the tracking of the stack size for variable-offset reads. This second fix is bundled in the same commit as the first one because they're inter-related. Before this patch, writes to the stack using registers containing a variable offset (as opposed to registers with fixed, known values) were not properly contributing to the function's needed stack size. As a result, it was possible for a program to verify, but then to attempt to read out-of-bounds data at runtime because a too small stack had been allocated for it. Each function tracks the size of the stack it needs in bpf_subprog_info.stack_depth, which is maintained by update_stack_depth(). For regular memory accesses, check_mem_access() was calling update_state_depth() but it was passing in only the fixed part of the offset register, ignoring the variable offset. This was incorrect; the minimum possible value of that register should be used instead. This tracking is now fixed by centralizing the tracking of stack size in grow_stack_state(), and by lifting the calls to grow_stack_state() to check_stack_access_within_bounds() as suggested by Andrii. The code is now simpler and more convincingly tracks the correct maximum stack size. check_stack_range_initialized() can now rely on enough stack having been allocated for the access; this helps with the fix for the first issue. A few tests were changed to also check the stack depth computation. The one that fails without this patch is verifier_var_off:stack_write_priv_vs_unpriv. Fixes: 01f810ace9ed3 ("bpf: Allow variable-offset stack access") Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Andrei Matei <andreimatei1@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20231208032519.260451-3-andreimatei1@gmail.com Closes: https://lore.kernel.org/bpf/CABWLsev9g8UP_c3a=1qbuZUi20tGoUXoU07FPf-5FLvhOKOY+Q@mail.gmail.com/
2023-12-07 22:25:18 -05:00
.errstr = "R0 invalid mem access 'scalar'",
.result_unpriv = REJECT,
.errstr_unpriv = "invalid read from stack R7 off=-16 size=8",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: two calls that receive map_value via arg=ptr_stack_of_caller. test1",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* 1st lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_8, 1),
/* 2nd lookup from map */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), /* 20 */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, /* 24 */
BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-16 */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_9, 1),
/* call 3rd func with fp-8, 0|1, fp-16, 0|1 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), /* 30 */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_9),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1), /* 34 */
BPF_EXIT_INSN(),
/* subprog 2 */
/* if arg2 == 1 do *arg1 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_2, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* if arg4 == 1 do *arg3 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_4, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 2, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 12, 22 },
.result = REJECT,
.errstr = "invalid access to map value, value_size=8 off=2 size=8",
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: two calls that receive map_value via arg=ptr_stack_of_caller. test2",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* 1st lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_8, 1),
/* 2nd lookup from map */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), /* 20 */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, /* 24 */
BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-16 */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_9, 1),
/* call 3rd func with fp-8, 0|1, fp-16, 0|1 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), /* 30 */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_9),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1), /* 34 */
BPF_EXIT_INSN(),
/* subprog 2 */
/* if arg2 == 1 do *arg1 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_2, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* if arg4 == 1 do *arg3 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_4, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 12, 22 },
.result = ACCEPT,
},
{
"calls: two jumps that receive map_value via arg=ptr_stack_of_jumper. test3",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* 1st lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -24, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -24),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_8, 1),
/* 2nd lookup from map */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -24),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_9, 0), // 26
BPF_JMP_IMM(BPF_JA, 0, 0, 2),
/* write map_value_ptr into stack frame of main prog at fp-16 */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_9, 1),
/* call 3rd func with fp-8, 0|1, fp-16, 0|1 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), // 30
BPF_MOV64_REG(BPF_REG_2, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_9),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1), // 34
BPF_JMP_IMM(BPF_JA, 0, 0, -30),
/* subprog 2 */
/* if arg2 == 1 do *arg1 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_2, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* if arg4 == 1 do *arg3 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_4, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 2, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, -8),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 12, 22 },
.result = REJECT,
.errstr = "invalid access to map value, value_size=8 off=2 size=8",
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: two calls that receive map_value_ptr_or_null via arg. test1",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* 1st lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_MOV64_IMM(BPF_REG_8, 1),
/* 2nd lookup from map */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-16 */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_MOV64_IMM(BPF_REG_9, 1),
/* call 3rd func with fp-8, 0|1, fp-16, 0|1 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_9),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* subprog 2 */
/* if arg2 == 1 do *arg1 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_2, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* if arg4 == 1 do *arg3 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_4, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 12, 22 },
.result = ACCEPT,
},
{
"calls: two calls that receive map_value_ptr_or_null via arg. test2",
.insns = {
/* main prog */
/* pass fp-16, fp-8 into a function */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_2),
/* 1st lookup from map */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_MOV64_IMM(BPF_REG_8, 1),
/* 2nd lookup from map */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-16 */
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_MOV64_IMM(BPF_REG_9, 1),
/* call 3rd func with fp-8, 0|1, fp-16, 0|1 */
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_8),
BPF_MOV64_REG(BPF_REG_3, BPF_REG_7),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_9),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* subprog 2 */
/* if arg2 == 1 do *arg1 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_2, 1, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
/* if arg4 == 0 do *arg3 = 0 */
BPF_JMP_IMM(BPF_JNE, BPF_REG_4, 0, 2),
/* fetch map_value_ptr from the stack of this function */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
/* write into map value */
BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.fixup_map_hash_8b = { 12, 22 },
.result = REJECT,
bpf: Small BPF verifier log improvements In particular these include: 1) Remove output of inv for scalars in print_verifier_state 2) Replace inv with scalar in verifier error messages 3) Remove _value suffixes for umin/umax/s32_min/etc (except map_value) 4) Remove output of id=0 5) Remove output of ref_obj_id=0 Signed-off-by: Mykola Lysenko <mykolal@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220301222745.1667206-1-mykolal@fb.com
2022-03-01 14:27:45 -08:00
.errstr = "R0 invalid mem access 'scalar'",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: pkt_ptr spill into caller stack",
.insns = {
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
/* spill unchecked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 2),
/* now the pkt range is verified, read pkt_ptr from stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_4, 0),
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.retval = POINTER_VALUE,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 2",
.insns = {
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
/* Marking is still kept, but not in all cases safe. */
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_ST_MEM(BPF_W, BPF_REG_4, 0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
/* spill unchecked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 2),
/* now the pkt range is verified, read pkt_ptr from stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_4, 0),
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "invalid access to packet",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 3",
.insns = {
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
/* Marking is still kept and safe here. */
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_ST_MEM(BPF_W, BPF_REG_4, 0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
/* spill unchecked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 3),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* now the pkt range is verified, read pkt_ptr from stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_4, 0),
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 1,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 4",
.insns = {
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
/* Check marking propagated. */
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_ST_MEM(BPF_W, BPF_REG_4, 0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
/* spill unchecked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 2),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.retval = 1,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 5",
.insns = {
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_4, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 3),
/* spill checked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "same insn cannot be used with different",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 6",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_4, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 3),
/* spill checked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "R4 invalid mem access",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 7",
.insns = {
BPF_MOV64_IMM(BPF_REG_2, 0),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_4, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 3),
/* spill checked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "R4 invalid mem access",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 8",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_0, BPF_REG_3, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_4, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_IMM(BPF_REG_5, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 3),
/* spill checked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: pkt_ptr spill into caller stack 9",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_0, BPF_REG_3, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_4, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data_end)),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
BPF_MOV64_IMM(BPF_REG_5, 0),
/* spill unchecked pkt_ptr into stack of caller */
BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0),
BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 2),
BPF_MOV64_IMM(BPF_REG_5, 1),
/* don't read back pkt_ptr from stack here */
/* write 4 bytes into packet */
BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
BPF_MOV64_REG(BPF_REG_0, BPF_REG_5),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.errstr = "invalid access to packet",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"calls: caller stack init to zero or map_value_or_null",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
/* fetch map_value_or_null or const_zero from stack */
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
/* store into map_value */
BPF_ST_MEM(BPF_W, BPF_REG_0, 0, 0),
BPF_EXIT_INSN(),
/* subprog 1 */
/* if (ctx == 0) return; */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 8),
/* else bpf_map_lookup() and *(fp - 8) = r0 */
BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
/* write map_value_ptr_or_null into stack frame of main prog at fp-8 */
BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.fixup_map_hash_8b = { 13 },
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"calls: stack init to zero and pruning",
.insns = {
/* first make allocated_stack 16 byte */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
/* now fork the execution such that the false branch
* of JGT insn will be verified second and it skisp zero
* init of fp-8 stack slot. If stack liveness marking
* is missing live_read marks from call map_lookup
* processing then pruning will incorrectly assume
* that fp-8 stack slot was unused in the fall-through
* branch and will accept the program incorrectly
*/
bpf: Allow reads from uninit stack This commits updates the following functions to allow reads from uninitialized stack locations when env->allow_uninit_stack option is enabled: - check_stack_read_fixed_off() - check_stack_range_initialized(), called from: - check_stack_read_var_off() - check_helper_mem_access() Such change allows to relax logic in stacksafe() to treat STACK_MISC and STACK_INVALID in a same way and make the following stack slot configurations equivalent: | Cached state | Current state | | stack slot | stack slot | |------------------+------------------| | STACK_INVALID or | STACK_INVALID or | | STACK_MISC | STACK_SPILL or | | | STACK_MISC or | | | STACK_ZERO or | | | STACK_DYNPTR | This leads to significant verification speed gains (see below). The idea was suggested by Andrii Nakryiko [1] and initial patch was created by Alexei Starovoitov [2]. Currently the env->allow_uninit_stack is allowed for programs loaded by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities. A number of test cases from verifier/*.c were expecting uninitialized stack access to be an error. These test cases were updated to execute in unprivileged mode (thus preserving the tests). The test progs/test_global_func10.c expected "invalid indirect read from stack" error message because of the access to uninitialized memory region. This error is no longer possible in privileged mode. The test is updated to provoke an error "invalid indirect access to stack" because of access to invalid stack address (such error is not verified by progs/test_global_func*.c series of tests). The following tests had to be removed because these can't be made unprivileged: - verifier/sock.c: - "sk_storage_get(map, skb->sk, &stack_value, 1): partially init stack_value" BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode. - verifier/var_off.c: - "indirect variable-offset stack access, max_off+size > max_initialized" - "indirect variable-offset stack access, uninitialized" These tests verify that access to uninitialized stack values is detected when stack offset is not a constant. However, variable stack access is prohibited in unprivileged mode, thus these tests are no longer valid. * * * Here is veristat log comparing this patch with current master on a set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg and cilium BPF binaries (see [3]): $ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log File Program States (A) States (B) States (DIFF) -------------------------- -------------------------- ---------- ---------- ---------------- bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%) bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%) bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%) bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%) bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%) bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%) pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%) strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%) strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%) xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%) xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%) -------------------------- -------------------------- ---------- ---------- ---------------- Note: I limited selection by states_pct<-30%. Inspection of differences in pyperf600_bpf_loop behavior shows that the following patch for the test removes almost all differences: - a/tools/testing/selftests/bpf/progs/pyperf.h + b/tools/testing/selftests/bpf/progs/pyperf.h @ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx) } if (event->pthread_match || !pidData->use_tls) { - void* frame_ptr; - FrameData frame; + void* frame_ptr = 0; + FrameData frame = {}; Symbol sym = {}; int cur_cpu = bpf_get_smp_processor_id(); W/o this patch the difference comes from the following pattern (for different variables): static bool get_frame_data(... FrameData *frame ...) { ... bpf_probe_read_user(&frame->f_code, ...); if (!frame->f_code) return false; ... bpf_probe_read_user(&frame->co_name, ...); if (frame->co_name) ...; } int __on_event(struct bpf_raw_tracepoint_args *ctx) { FrameData frame; ... get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback ... } SEC("raw_tracepoint/kfree_skb") int on_event(struct bpf_raw_tracepoint_args* ctx) { ... ret |= __on_event(ctx); ret |= __on_event(ctx); ... } With regards to value `frame->co_name` the following is important: - Because of the conditional `if (!frame->f_code)` each call to __on_event() produces two states, one with `frame->co_name` marked as STACK_MISC, another with it as is (and marked STACK_INVALID on a first call). - The call to bpf_probe_read_user() does not mark stack slots corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks these slots as BPF_MISC, this happens because of the following loop in the check_helper_call(): for (i = 0; i < meta.access_size; i++) { err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1, false); if (err) return err; } Note the size of the write, it is a one byte write for each byte touched by a helper. The BPF_B write does not lead to write marks for the target stack slot. - Which means that w/o this patch when second __on_event() call is verified `if (frame->co_name)` will propagate read marks first to a stack slot with STACK_MISC marks and second to a stack slot with STACK_INVALID marks and these states would be considered different. [1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/ [2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/ [3] git@github.com:anakryiko/cilium.git Suggested-by: Andrii Nakryiko <andrii@kernel.org> Co-developed-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-19 22:04:26 +02:00
BPF_EMIT_CALL(BPF_FUNC_get_prandom_u32),
BPF_JMP_IMM(BPF_JGT, BPF_REG_0, 2, 2),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_JMP_IMM(BPF_JA, 0, 0, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
bpf: Allow reads from uninit stack This commits updates the following functions to allow reads from uninitialized stack locations when env->allow_uninit_stack option is enabled: - check_stack_read_fixed_off() - check_stack_range_initialized(), called from: - check_stack_read_var_off() - check_helper_mem_access() Such change allows to relax logic in stacksafe() to treat STACK_MISC and STACK_INVALID in a same way and make the following stack slot configurations equivalent: | Cached state | Current state | | stack slot | stack slot | |------------------+------------------| | STACK_INVALID or | STACK_INVALID or | | STACK_MISC | STACK_SPILL or | | | STACK_MISC or | | | STACK_ZERO or | | | STACK_DYNPTR | This leads to significant verification speed gains (see below). The idea was suggested by Andrii Nakryiko [1] and initial patch was created by Alexei Starovoitov [2]. Currently the env->allow_uninit_stack is allowed for programs loaded by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities. A number of test cases from verifier/*.c were expecting uninitialized stack access to be an error. These test cases were updated to execute in unprivileged mode (thus preserving the tests). The test progs/test_global_func10.c expected "invalid indirect read from stack" error message because of the access to uninitialized memory region. This error is no longer possible in privileged mode. The test is updated to provoke an error "invalid indirect access to stack" because of access to invalid stack address (such error is not verified by progs/test_global_func*.c series of tests). The following tests had to be removed because these can't be made unprivileged: - verifier/sock.c: - "sk_storage_get(map, skb->sk, &stack_value, 1): partially init stack_value" BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode. - verifier/var_off.c: - "indirect variable-offset stack access, max_off+size > max_initialized" - "indirect variable-offset stack access, uninitialized" These tests verify that access to uninitialized stack values is detected when stack offset is not a constant. However, variable stack access is prohibited in unprivileged mode, thus these tests are no longer valid. * * * Here is veristat log comparing this patch with current master on a set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg and cilium BPF binaries (see [3]): $ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log File Program States (A) States (B) States (DIFF) -------------------------- -------------------------- ---------- ---------- ---------------- bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%) bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%) bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%) bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%) bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%) bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%) pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%) strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%) strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%) xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%) xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%) -------------------------- -------------------------- ---------- ---------- ---------------- Note: I limited selection by states_pct<-30%. Inspection of differences in pyperf600_bpf_loop behavior shows that the following patch for the test removes almost all differences: - a/tools/testing/selftests/bpf/progs/pyperf.h + b/tools/testing/selftests/bpf/progs/pyperf.h @ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx) } if (event->pthread_match || !pidData->use_tls) { - void* frame_ptr; - FrameData frame; + void* frame_ptr = 0; + FrameData frame = {}; Symbol sym = {}; int cur_cpu = bpf_get_smp_processor_id(); W/o this patch the difference comes from the following pattern (for different variables): static bool get_frame_data(... FrameData *frame ...) { ... bpf_probe_read_user(&frame->f_code, ...); if (!frame->f_code) return false; ... bpf_probe_read_user(&frame->co_name, ...); if (frame->co_name) ...; } int __on_event(struct bpf_raw_tracepoint_args *ctx) { FrameData frame; ... get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback ... } SEC("raw_tracepoint/kfree_skb") int on_event(struct bpf_raw_tracepoint_args* ctx) { ... ret |= __on_event(ctx); ret |= __on_event(ctx); ... } With regards to value `frame->co_name` the following is important: - Because of the conditional `if (!frame->f_code)` each call to __on_event() produces two states, one with `frame->co_name` marked as STACK_MISC, another with it as is (and marked STACK_INVALID on a first call). - The call to bpf_probe_read_user() does not mark stack slots corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks these slots as BPF_MISC, this happens because of the following loop in the check_helper_call(): for (i = 0; i < meta.access_size; i++) { err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1, false); if (err) return err; } Note the size of the write, it is a one byte write for each byte touched by a helper. The BPF_B write does not lead to write marks for the target stack slot. - Which means that w/o this patch when second __on_event() call is verified `if (frame->co_name)` will propagate read marks first to a stack slot with STACK_MISC marks and second to a stack slot with STACK_INVALID marks and these states would be considered different. [1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/ [2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/ [3] git@github.com:anakryiko/cilium.git Suggested-by: Andrii Nakryiko <andrii@kernel.org> Co-developed-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-19 22:04:26 +02:00
BPF_MOV64_IMM(BPF_REG_0, 0),
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
BPF_EXIT_INSN(),
},
bpf: Allow reads from uninit stack This commits updates the following functions to allow reads from uninitialized stack locations when env->allow_uninit_stack option is enabled: - check_stack_read_fixed_off() - check_stack_range_initialized(), called from: - check_stack_read_var_off() - check_helper_mem_access() Such change allows to relax logic in stacksafe() to treat STACK_MISC and STACK_INVALID in a same way and make the following stack slot configurations equivalent: | Cached state | Current state | | stack slot | stack slot | |------------------+------------------| | STACK_INVALID or | STACK_INVALID or | | STACK_MISC | STACK_SPILL or | | | STACK_MISC or | | | STACK_ZERO or | | | STACK_DYNPTR | This leads to significant verification speed gains (see below). The idea was suggested by Andrii Nakryiko [1] and initial patch was created by Alexei Starovoitov [2]. Currently the env->allow_uninit_stack is allowed for programs loaded by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities. A number of test cases from verifier/*.c were expecting uninitialized stack access to be an error. These test cases were updated to execute in unprivileged mode (thus preserving the tests). The test progs/test_global_func10.c expected "invalid indirect read from stack" error message because of the access to uninitialized memory region. This error is no longer possible in privileged mode. The test is updated to provoke an error "invalid indirect access to stack" because of access to invalid stack address (such error is not verified by progs/test_global_func*.c series of tests). The following tests had to be removed because these can't be made unprivileged: - verifier/sock.c: - "sk_storage_get(map, skb->sk, &stack_value, 1): partially init stack_value" BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode. - verifier/var_off.c: - "indirect variable-offset stack access, max_off+size > max_initialized" - "indirect variable-offset stack access, uninitialized" These tests verify that access to uninitialized stack values is detected when stack offset is not a constant. However, variable stack access is prohibited in unprivileged mode, thus these tests are no longer valid. * * * Here is veristat log comparing this patch with current master on a set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg and cilium BPF binaries (see [3]): $ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log File Program States (A) States (B) States (DIFF) -------------------------- -------------------------- ---------- ---------- ---------------- bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%) bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%) bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%) bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%) bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%) bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%) pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%) strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%) strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%) xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%) xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%) -------------------------- -------------------------- ---------- ---------- ---------------- Note: I limited selection by states_pct<-30%. Inspection of differences in pyperf600_bpf_loop behavior shows that the following patch for the test removes almost all differences: - a/tools/testing/selftests/bpf/progs/pyperf.h + b/tools/testing/selftests/bpf/progs/pyperf.h @ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx) } if (event->pthread_match || !pidData->use_tls) { - void* frame_ptr; - FrameData frame; + void* frame_ptr = 0; + FrameData frame = {}; Symbol sym = {}; int cur_cpu = bpf_get_smp_processor_id(); W/o this patch the difference comes from the following pattern (for different variables): static bool get_frame_data(... FrameData *frame ...) { ... bpf_probe_read_user(&frame->f_code, ...); if (!frame->f_code) return false; ... bpf_probe_read_user(&frame->co_name, ...); if (frame->co_name) ...; } int __on_event(struct bpf_raw_tracepoint_args *ctx) { FrameData frame; ... get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback ... } SEC("raw_tracepoint/kfree_skb") int on_event(struct bpf_raw_tracepoint_args* ctx) { ... ret |= __on_event(ctx); ret |= __on_event(ctx); ... } With regards to value `frame->co_name` the following is important: - Because of the conditional `if (!frame->f_code)` each call to __on_event() produces two states, one with `frame->co_name` marked as STACK_MISC, another with it as is (and marked STACK_INVALID on a first call). - The call to bpf_probe_read_user() does not mark stack slots corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks these slots as BPF_MISC, this happens because of the following loop in the check_helper_call(): for (i = 0; i < meta.access_size; i++) { err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1, false); if (err) return err; } Note the size of the write, it is a one byte write for each byte touched by a helper. The BPF_B write does not lead to write marks for the target stack slot. - Which means that w/o this patch when second __on_event() call is verified `if (frame->co_name)` will propagate read marks first to a stack slot with STACK_MISC marks and second to a stack slot with STACK_INVALID marks and these states would be considered different. [1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/ [2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/ [3] git@github.com:anakryiko/cilium.git Suggested-by: Andrii Nakryiko <andrii@kernel.org> Co-developed-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-19 22:04:26 +02:00
.fixup_map_hash_48b = { 7 },
bpf: verifier: Refactor helper access type tracking Previously, the verifier was treating all PTR_TO_STACK registers passed to a helper call as potentially written to by the helper. However, all calls to check_stack_range_initialized() already have precise access type information available. Rather than treat ACCESS_HELPER as a proxy for BPF_WRITE, pass enum bpf_access_type to check_stack_range_initialized() to more precisely track helper arguments. One benefit from this precision is that registers tracked as valid spills and passed as a read-only helper argument remain tracked after the call. Rather than being marked STACK_MISC afterwards. An additional benefit is the verifier logs are also more precise. For this particular error, users will enjoy a slightly clearer message. See included selftest updates for examples. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/ff885c0e5859e0cd12077c3148ff0754cad4f7ed.1736886479.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-01-14 13:28:44 -07:00
.errstr_unpriv = "invalid read from stack R2 off -8+0 size 8",
bpf: Allow reads from uninit stack This commits updates the following functions to allow reads from uninitialized stack locations when env->allow_uninit_stack option is enabled: - check_stack_read_fixed_off() - check_stack_range_initialized(), called from: - check_stack_read_var_off() - check_helper_mem_access() Such change allows to relax logic in stacksafe() to treat STACK_MISC and STACK_INVALID in a same way and make the following stack slot configurations equivalent: | Cached state | Current state | | stack slot | stack slot | |------------------+------------------| | STACK_INVALID or | STACK_INVALID or | | STACK_MISC | STACK_SPILL or | | | STACK_MISC or | | | STACK_ZERO or | | | STACK_DYNPTR | This leads to significant verification speed gains (see below). The idea was suggested by Andrii Nakryiko [1] and initial patch was created by Alexei Starovoitov [2]. Currently the env->allow_uninit_stack is allowed for programs loaded by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities. A number of test cases from verifier/*.c were expecting uninitialized stack access to be an error. These test cases were updated to execute in unprivileged mode (thus preserving the tests). The test progs/test_global_func10.c expected "invalid indirect read from stack" error message because of the access to uninitialized memory region. This error is no longer possible in privileged mode. The test is updated to provoke an error "invalid indirect access to stack" because of access to invalid stack address (such error is not verified by progs/test_global_func*.c series of tests). The following tests had to be removed because these can't be made unprivileged: - verifier/sock.c: - "sk_storage_get(map, skb->sk, &stack_value, 1): partially init stack_value" BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode. - verifier/var_off.c: - "indirect variable-offset stack access, max_off+size > max_initialized" - "indirect variable-offset stack access, uninitialized" These tests verify that access to uninitialized stack values is detected when stack offset is not a constant. However, variable stack access is prohibited in unprivileged mode, thus these tests are no longer valid. * * * Here is veristat log comparing this patch with current master on a set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg and cilium BPF binaries (see [3]): $ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log File Program States (A) States (B) States (DIFF) -------------------------- -------------------------- ---------- ---------- ---------------- bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%) bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%) bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%) bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%) bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%) bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%) bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%) pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%) strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%) strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%) xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%) xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%) -------------------------- -------------------------- ---------- ---------- ---------------- Note: I limited selection by states_pct<-30%. Inspection of differences in pyperf600_bpf_loop behavior shows that the following patch for the test removes almost all differences: - a/tools/testing/selftests/bpf/progs/pyperf.h + b/tools/testing/selftests/bpf/progs/pyperf.h @ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx) } if (event->pthread_match || !pidData->use_tls) { - void* frame_ptr; - FrameData frame; + void* frame_ptr = 0; + FrameData frame = {}; Symbol sym = {}; int cur_cpu = bpf_get_smp_processor_id(); W/o this patch the difference comes from the following pattern (for different variables): static bool get_frame_data(... FrameData *frame ...) { ... bpf_probe_read_user(&frame->f_code, ...); if (!frame->f_code) return false; ... bpf_probe_read_user(&frame->co_name, ...); if (frame->co_name) ...; } int __on_event(struct bpf_raw_tracepoint_args *ctx) { FrameData frame; ... get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback ... } SEC("raw_tracepoint/kfree_skb") int on_event(struct bpf_raw_tracepoint_args* ctx) { ... ret |= __on_event(ctx); ret |= __on_event(ctx); ... } With regards to value `frame->co_name` the following is important: - Because of the conditional `if (!frame->f_code)` each call to __on_event() produces two states, one with `frame->co_name` marked as STACK_MISC, another with it as is (and marked STACK_INVALID on a first call). - The call to bpf_probe_read_user() does not mark stack slots corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks these slots as BPF_MISC, this happens because of the following loop in the check_helper_call(): for (i = 0; i < meta.access_size; i++) { err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1, false); if (err) return err; } Note the size of the write, it is a one byte write for each byte touched by a helper. The BPF_B write does not lead to write marks for the target stack slot. - Which means that w/o this patch when second __on_event() call is verified `if (frame->co_name)` will propagate read marks first to a stack slot with STACK_MISC marks and second to a stack slot with STACK_INVALID marks and these states would be considered different. [1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/ [2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/ [3] git@github.com:anakryiko/cilium.git Suggested-by: Andrii Nakryiko <andrii@kernel.org> Co-developed-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-19 22:04:26 +02:00
.result_unpriv = REJECT,
/* in privileged mode reads from uninitialized stack locations are permitted */
.result = ACCEPT,
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
},
{
"calls: ctx read at start of subprog",
.insns = {
BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5),
BPF_JMP_REG(BPF_JSGT, BPF_REG_0, BPF_REG_0, 0),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
.errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.result_unpriv = REJECT,
.result = ACCEPT,
},
{
"calls: cross frame pruning",
.insns = {
/* r8 = !!random();
* call pruner()
* if (r8)
* do something bad;
*/
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV64_IMM(BPF_REG_8, 1),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_1, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
.errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for",
selftests: bpf: break up the rest of test_verifier Break up the rest of test_verifier tests into separate files. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-25 15:24:44 -08:00
.errstr = "!read_ok",
.result = REJECT,
},
bpf: verifier: propagate liveness on all frames Commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") connected up parentage chains of all frames of the stack. It didn't, however, ensure propagate_liveness() propagates all liveness information along those chains. This means pruning happening in the callee may generate explored states with incomplete liveness for the chains in lower frames of the stack. The included selftest is similar to the prior one from commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences"), where callee would prune regardless of the difference in r8 state. Now we also initialize r9 to 0 or 1 based on a result from get_random(). r9 is never read so the walk with r9 = 0 gets pruned (correctly) after the walk with r9 = 1 completes. The selftest is so arranged that the pruning will happen in the callee. Since callee does not propagate read marks of r8, the explored state at the pruning point prior to the callee will now ignore r8. Propagate liveness on all frames of the stack when pruning. Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-21 14:34:36 -07:00
{
"calls: cross frame pruning - liveness propagation",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_IMM(BPF_REG_8, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV64_IMM(BPF_REG_8, 1),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
BPF_MOV64_IMM(BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_MOV64_IMM(BPF_REG_9, 1),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
bpf: Support bpf program calling kernel function This patch adds support to BPF verifier to allow bpf program calling kernel function directly. The use case included in this set is to allow bpf-tcp-cc to directly call some tcp-cc helper functions (e.g. "tcp_cong_avoid_ai()"). Those functions have already been used by some kernel tcp-cc implementations. This set will also allow the bpf-tcp-cc program to directly call the kernel tcp-cc implementation, For example, a bpf_dctcp may only want to implement its own dctcp_cwnd_event() and reuse other dctcp_*() directly from the kernel tcp_dctcp.c instead of reimplementing (or copy-and-pasting) them. The tcp-cc kernel functions mentioned above will be white listed for the struct_ops bpf-tcp-cc programs to use in a later patch. The white listed functions are not bounded to a fixed ABI contract. Those functions have already been used by the existing kernel tcp-cc. If any of them has changed, both in-tree and out-of-tree kernel tcp-cc implementations have to be changed. The same goes for the struct_ops bpf-tcp-cc programs which have to be adjusted accordingly. This patch is to make the required changes in the bpf verifier. First change is in btf.c, it adds a case in "btf_check_func_arg_match()". When the passed in "btf->kernel_btf == true", it means matching the verifier regs' states with a kernel function. This will handle the PTR_TO_BTF_ID reg. It also maps PTR_TO_SOCK_COMMON, PTR_TO_SOCKET, and PTR_TO_TCP_SOCK to its kernel's btf_id. In the later libbpf patch, the insn calling a kernel function will look like: insn->code == (BPF_JMP | BPF_CALL) insn->src_reg == BPF_PSEUDO_KFUNC_CALL /* <- new in this patch */ insn->imm == func_btf_id /* btf_id of the running kernel */ [ For the future calling function-in-kernel-module support, an array of module btf_fds can be passed at the load time and insn->off can be used to index into this array. ] At the early stage of verifier, the verifier will collect all kernel function calls into "struct bpf_kfunc_desc". Those descriptors are stored in "prog->aux->kfunc_tab" and will be available to the JIT. Since this "add" operation is similar to the current "add_subprog()" and looking for the same insn->code, they are done together in the new "add_subprog_and_kfunc()". In the "do_check()" stage, the new "check_kfunc_call()" is added to verify the kernel function call instruction: 1. Ensure the kernel function can be used by a particular BPF_PROG_TYPE. A new bpf_verifier_ops "check_kfunc_call" is added to do that. The bpf-tcp-cc struct_ops program will implement this function in a later patch. 2. Call "btf_check_kfunc_args_match()" to ensure the regs can be used as the args of a kernel function. 3. Mark the regs' type, subreg_def, and zext_dst. At the later do_misc_fixups() stage, the new fixup_kfunc_call() will replace the insn->imm with the function address (relative to __bpf_call_base). If needed, the jit can find the btf_func_model by calling the new bpf_jit_find_kfunc_model(prog, insn). With the imm set to the function address, "bpftool prog dump xlated" will be able to display the kernel function calls the same way as it displays other bpf helper calls. gpl_compatible program is required to call kernel function. This feature currently requires JIT. The verifier selftests are adjusted because of the changes in the verbose log in add_subprog_and_kfunc(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210325015142.1544736-1-kafai@fb.com
2021-03-24 18:51:42 -07:00
.errstr_unpriv = "loading/calling other bpf or kernel functions are allowed for",
bpf: verifier: propagate liveness on all frames Commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") connected up parentage chains of all frames of the stack. It didn't, however, ensure propagate_liveness() propagates all liveness information along those chains. This means pruning happening in the callee may generate explored states with incomplete liveness for the chains in lower frames of the stack. The included selftest is similar to the prior one from commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences"), where callee would prune regardless of the difference in r8 state. Now we also initialize r9 to 0 or 1 based on a result from get_random(). r9 is never read so the walk with r9 = 0 gets pruned (correctly) after the walk with r9 = 1 completes. The selftest is so arranged that the pruning will happen in the callee. Since callee does not propagate read marks of r8, the explored state at the pruning point prior to the callee will now ignore r8. Propagate liveness on all frames of the stack when pruning. Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-21 14:34:36 -07:00
.errstr = "!read_ok",
.result = REJECT,
},
selftests/bpf: verify states_equal() maintains idmap across all frames A test case that would erroneously pass verification if verifier.c:states_equal() maintains separate register ID mappings for call frames. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20221209135733.28851-5-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-09 15:57:30 +02:00
/* Make sure that verifier.c:states_equal() considers IDs from all
* frames when building 'idmap' for check_ids().
*/
{
"calls: check_ids() across call boundary",
.insns = {
/* Function main() */
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
/* fp[-24] = map_lookup_elem(...) ; get a MAP_VALUE_PTR_OR_NULL with some ID */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1,
0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_STX_MEM(BPF_DW, BPF_REG_FP, BPF_REG_0, -24),
/* fp[-32] = map_lookup_elem(...) ; get a MAP_VALUE_PTR_OR_NULL with some ID */
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1,
0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
BPF_STX_MEM(BPF_DW, BPF_REG_FP, BPF_REG_0, -32),
/* call foo(&fp[-24], &fp[-32]) ; both arguments have IDs in the current
* ; stack frame
*/
BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -24),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -32),
BPF_CALL_REL(2),
/* exit 0 */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
/* Function foo()
*
* r9 = &frame[0].fp[-24] ; save arguments in the callee saved registers,
* r8 = &frame[0].fp[-32] ; arguments are pointers to pointers to map value
*/
BPF_MOV64_REG(BPF_REG_9, BPF_REG_1),
BPF_MOV64_REG(BPF_REG_8, BPF_REG_2),
/* r7 = ktime_get_ns() */
BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
/* r6 = ktime_get_ns() */
BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
/* if r6 > r7 goto +1 ; no new information about the state is derived from
* ; this check, thus produced verifier states differ
* ; only in 'insn_idx'
* r9 = r8
*/
BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_7, 1),
BPF_MOV64_REG(BPF_REG_9, BPF_REG_8),
/* r9 = *r9 ; verifier get's to this point via two paths:
* ; (I) one including r9 = r8, verified first;
* ; (II) one excluding r9 = r8, verified next.
* ; After load of *r9 to r9 the frame[0].fp[-24].id == r9.id.
* ; Suppose that checkpoint is created here via path (I).
* ; When verifying via (II) the r9.id must be compared against
* ; frame[0].fp[-24].id, otherwise (I) and (II) would be
* ; incorrectly deemed equivalent.
* if r9 == 0 goto <exit>
*/
BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_9, 0),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_9, 0, 1),
/* r8 = *r8 ; read map value via r8, this is not safe
* r0 = *r8 ; because r8 might be not equal to r9.
*/
BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_8, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_8, 0),
/* exit 0 */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.flags = BPF_F_TEST_STATE_FREQ,
.fixup_map_hash_8b = { 3, 9 },
.result = REJECT,
.errstr = "R8 invalid mem access 'map_value_or_null'",
.result_unpriv = REJECT,
.errstr_unpriv = "",
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
},
selftests/bpf: Negative test case for ref_obj_id in args This patch adds a test case, as shown below, for the verifier error "more than one arg with ref_obj_id". 0: (b7) r2 = 20 1: (b7) r3 = 0 2: (18) r1 = 0xffff92cee3cbc600 4: (85) call bpf_ringbuf_reserve#131 5: (55) if r0 == 0x0 goto pc+3 6: (bf) r1 = r0 7: (bf) r2 = r0 8: (85) call bpf_tcp_raw_gen_syncookie_ipv4#204 9: (95) exit This error is currently incorrectly reported as a verifier bug, with a warning. The next patch in this series will address that. Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com> Link: https://lore.kernel.org/r/3ba78e6cda47ccafd6ea70dadbc718d020154664.1751463262.git.paul.chaignon@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-07-02 15:53:23 +02:00
{
"calls: several args with ref_obj_id",
.insns = {
/* Reserve at least sizeof(struct iphdr) bytes in the ring buffer.
* With a smaller size, the verifier would reject the call to
* bpf_tcp_raw_gen_syncookie_ipv4 before we can reach the
* ref_obj_id error.
*/
BPF_MOV64_IMM(BPF_REG_2, 20),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),
/* if r0 == 0 goto <exit> */
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_tcp_raw_gen_syncookie_ipv4),
BPF_EXIT_INSN(),
},
.fixup_map_ringbuf = { 2 },
.result = REJECT,
.errstr = "more than one arg with ref_obj_id",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
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