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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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37cce22dbd
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>
155 lines
3.4 KiB
C
155 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Converted from tools/testing/selftests/bpf/verifier/int_ptr.c */
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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SEC("socket")
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__description("arg pointer to long uninitialized")
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__success
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__naked void arg_ptr_to_long_uninitialized(void)
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{
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asm volatile (" \
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/* bpf_strtoul arg1 (buf) */ \
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r7 = r10; \
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r7 += -8; \
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r0 = 0x00303036; \
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*(u64*)(r7 + 0) = r0; \
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r1 = r7; \
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/* bpf_strtoul arg2 (buf_len) */ \
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r2 = 4; \
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/* bpf_strtoul arg3 (flags) */ \
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r3 = 0; \
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/* bpf_strtoul arg4 (res) */ \
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r7 += -8; \
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r4 = r7; \
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/* bpf_strtoul() */ \
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call %[bpf_strtoul]; \
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r0 = 1; \
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exit; \
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" :
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: __imm(bpf_strtoul)
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: __clobber_all);
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}
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SEC("socket")
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__description("arg pointer to long half-uninitialized")
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__success
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__retval(0)
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__naked void ptr_to_long_half_uninitialized(void)
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{
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asm volatile (" \
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/* bpf_strtoul arg1 (buf) */ \
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r7 = r10; \
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r7 += -8; \
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r0 = 0x00303036; \
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*(u64*)(r7 + 0) = r0; \
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r1 = r7; \
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/* bpf_strtoul arg2 (buf_len) */ \
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r2 = 4; \
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/* bpf_strtoul arg3 (flags) */ \
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r3 = 0; \
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/* bpf_strtoul arg4 (res) */ \
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r7 += -8; \
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*(u32*)(r7 + 0) = r0; \
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r4 = r7; \
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/* bpf_strtoul() */ \
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call %[bpf_strtoul]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_strtoul)
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: __clobber_all);
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}
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SEC("cgroup/sysctl")
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__description("arg pointer to long misaligned")
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__failure __msg("misaligned stack access off 0+-20+0 size 8")
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__naked void arg_ptr_to_long_misaligned(void)
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{
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asm volatile (" \
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/* bpf_strtoul arg1 (buf) */ \
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r7 = r10; \
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r7 += -8; \
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r0 = 0x00303036; \
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*(u64*)(r7 + 0) = r0; \
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r1 = r7; \
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/* bpf_strtoul arg2 (buf_len) */ \
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r2 = 4; \
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/* bpf_strtoul arg3 (flags) */ \
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r3 = 0; \
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/* bpf_strtoul arg4 (res) */ \
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r7 += -12; \
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r0 = 0; \
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*(u32*)(r7 + 0) = r0; \
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*(u64*)(r7 + 4) = r0; \
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r4 = r7; \
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/* bpf_strtoul() */ \
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call %[bpf_strtoul]; \
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r0 = 1; \
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exit; \
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" :
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: __imm(bpf_strtoul)
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: __clobber_all);
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}
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SEC("cgroup/sysctl")
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__description("arg pointer to long size < sizeof(long)")
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__failure __msg("invalid write to stack R4 off=-4 size=8")
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__naked void to_long_size_sizeof_long(void)
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{
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asm volatile (" \
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/* bpf_strtoul arg1 (buf) */ \
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r7 = r10; \
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r7 += -16; \
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r0 = 0x00303036; \
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*(u64*)(r7 + 0) = r0; \
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r1 = r7; \
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/* bpf_strtoul arg2 (buf_len) */ \
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r2 = 4; \
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/* bpf_strtoul arg3 (flags) */ \
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r3 = 0; \
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/* bpf_strtoul arg4 (res) */ \
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r7 += 12; \
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*(u32*)(r7 + 0) = r0; \
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r4 = r7; \
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/* bpf_strtoul() */ \
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call %[bpf_strtoul]; \
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r0 = 1; \
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exit; \
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" :
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: __imm(bpf_strtoul)
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: __clobber_all);
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}
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SEC("cgroup/sysctl")
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__description("arg pointer to long initialized")
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__success
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__naked void arg_ptr_to_long_initialized(void)
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{
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asm volatile (" \
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/* bpf_strtoul arg1 (buf) */ \
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r7 = r10; \
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r7 += -8; \
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r0 = 0x00303036; \
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*(u64*)(r7 + 0) = r0; \
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r1 = r7; \
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/* bpf_strtoul arg2 (buf_len) */ \
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r2 = 4; \
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/* bpf_strtoul arg3 (flags) */ \
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r3 = 0; \
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/* bpf_strtoul arg4 (res) */ \
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r7 += -8; \
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*(u64*)(r7 + 0) = r0; \
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r4 = r7; \
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/* bpf_strtoul() */ \
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call %[bpf_strtoul]; \
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r0 = 1; \
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exit; \
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" :
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: __imm(bpf_strtoul)
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: __clobber_all);
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}
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char _license[] SEC("license") = "GPL";
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