linux/kernel/bpf
David Vernet a8e03b6bbb bpf: Allow invoking kfuncs from BPF_PROG_TYPE_SYSCALL progs
Currently, a set of core BPF kfuncs (e.g. bpf_task_*, bpf_cgroup_*,
bpf_cpumask_*, etc) cannot be invoked from BPF_PROG_TYPE_SYSCALL
programs. The whitelist approach taken for enabling kfuncs makes sense:
it not safe to call these kfuncs from every program type. For example,
it may not be safe to call bpf_task_acquire() in an fentry to
free_task().

BPF_PROG_TYPE_SYSCALL, on the other hand, is a perfectly safe program
type from which to invoke these kfuncs, as it's a very controlled
environment, and we should never be able to run into any of the typical
problems such as recursive invoations, acquiring references on freeing
kptrs, etc. Being able to invoke these kfuncs would be useful, as
BPF_PROG_TYPE_SYSCALL can be invoked with BPF_PROG_RUN, and would
therefore enable user space programs to synchronously call into BPF to
manipulate these kptrs.

This patch therefore enables invoking the aforementioned core kfuncs
from BPF_PROG_TYPE_SYSCALL progs.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240405143041.632519-2-void@manifault.com
2024-04-05 10:56:09 -07:00
..
preload
arena.c bpf,arena: Use helper sizeof_field in struct accessors 2024-03-28 18:31:36 -07:00
arraymap.c bpf: inline bpf_map_lookup_elem() for PERCPU_ARRAY maps 2024-04-03 10:29:56 -07:00
bloom_filter.c bpf: Check bloom filter map value size 2024-03-27 09:56:17 -07:00
bpf_cgrp_storage.c bpf: Enable bpf_cgrp_storage for cgroup1 non-attach case 2023-12-08 17:08:18 -08:00
bpf_inode_storage.c
bpf_iter.c bpf: move sleepable flag from bpf_prog_aux to bpf_prog 2024-03-11 16:41:25 -07:00
bpf_local_storage.c bpf: Allow compiler to inline most of bpf_local_storage_lookup() 2024-02-11 14:06:24 -08:00
bpf_lru_list.c
bpf_lru_list.h bpf: lru: Remove unused declaration bpf_lru_promote() 2023-08-08 17:21:42 -07:00
bpf_lsm.c bpf: Minor clean-up to sleepable_lsm_hooks BTF set 2024-02-01 18:37:45 +01:00
bpf_struct_ops.c bpf: Check return from set_memory_rox() 2024-03-18 14:18:47 -07:00
bpf_task_storage.c
btf.c bpf: Recognize btf_decl_tag("arg: Arena") as PTR_TO_ARENA. 2024-03-11 15:37:24 -07:00
cgroup.c bpf: Allow helper bpf_get_[ns_]current_pid_tgid() for all prog types 2024-03-19 14:24:07 -07:00
cgroup_iter.c bpf: Let verifier consider {task,cgroup} is trusted in bpf_iter_reg 2023-11-07 15:24:25 -08:00
core.c bpf: add special internal-only MOV instruction to resolve per-CPU addrs 2024-04-03 10:29:55 -07:00
cpumap.c bpf: report RCU QS in cpumap kthread 2024-03-20 21:05:43 -07:00
cpumask.c bpf: Allow invoking kfuncs from BPF_PROG_TYPE_SYSCALL progs 2024-04-05 10:56:09 -07:00
devmap.c bpf: Fix DEVMAP_HASH overflow check on 32-bit arches 2024-03-07 20:02:38 -08:00
disasm.c bpf: add special internal-only MOV instruction to resolve per-CPU addrs 2024-04-03 10:29:55 -07:00
disasm.h
dispatcher.c bpf: Use arch_bpf_trampoline_size 2023-12-06 17:17:20 -08:00
hashtab.c bpf: inline bpf_map_lookup_elem() helper for PERCPU_HASH map 2024-04-03 10:29:56 -07:00
helpers.c bpf: Allow invoking kfuncs from BPF_PROG_TYPE_SYSCALL progs 2024-04-05 10:56:09 -07:00
inode.c bpf: Support symbolic BPF FS delegation mount options 2024-01-24 16:21:02 -08:00
Kconfig bpf: Merge two CONFIG_BPF entries 2024-02-07 16:38:20 -08:00
link_iter.c
local_storage.c
log.c bpf: Replace deprecated strncpy with strscpy 2024-04-03 16:57:41 +02:00
lpm_trie.c bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie. 2024-03-29 11:10:41 -07:00
Makefile bpf: Introduce bpf_arena. 2024-03-11 15:37:23 -07:00
map_in_map.c bpf: Optimize the free of inner map 2023-12-04 17:50:26 -08:00
map_in_map.h bpf: Add map and need_defer parameters to .map_fd_put_ptr() 2023-12-04 17:50:26 -08:00
map_iter.c bpf: treewide: Annotate BPF kfuncs in BTF 2024-01-31 20:40:56 -08:00
memalloc.c bpf: Remove unnecessary cpu == 0 check in memalloc 2024-01-04 10:18:14 -08:00
mmap_unlock_work.h
mprog.c bpf: Handle bpf_mprog_query with NULL entry 2023-10-06 17:11:20 -07:00
net_namespace.c
offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-09-21 21:49:45 +02:00
percpu_freelist.c
percpu_freelist.h
prog_iter.c
queue_stack_maps.c bpf: Avoid deadlock when using queue and stack maps from NMI 2023-09-11 19:04:49 -07:00
reuseport_array.c
ringbuf.c bpf: Fold smp_mb__before_atomic() into atomic_set_release() 2023-10-24 14:26:07 +02:00
stackmap.c bpf: Fix stackmap overflow check on 32-bit arches 2024-03-07 20:06:25 -08:00
syscall.c bpf: support BPF cookie in raw tracepoint (raw_tp, tp_btf) programs 2024-03-19 23:05:34 -07:00
sysfs_btf.c
task_iter.c bpf: Fix an issue due to uninitialized bpf_iter_task 2024-02-19 12:28:15 +01:00
tcx.c bpf, tcx: Get rid of tcx_link_const 2023-10-23 15:01:53 -07:00
tnum.c bpf: simplify tnum output if a fully known constant 2023-12-02 11:36:51 -08:00
token.c bpf,token: Use BIT_ULL() to convert the bit mask 2024-01-29 20:04:55 -08:00
trampoline.c bpf: Improve program stats run-time calculation 2024-04-02 16:51:15 +02:00
verifier.c bpf: allow invoking bpf_for_each_map_elem with different maps 2024-04-05 10:31:17 -07:00