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bpf: cleanup aux->used_maps after jit

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In commit b4ce5923e7 ("bpf, x86: add new map type: instructions array")
env->used_map was copied to func[i]->aux->used_maps before jitting.
Clear these fields out after jitting such that pointer to freed memory
(env->used_maps is freed later) are not kept in a live data structure.

The reason why the copies were initially added is explained in
https://lore.kernel.org/bpf/20251105090410.1250500-1-a.s.protopopov@gmail.com

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Fixes: b4ce5923e7 ("bpf, x86: add new map type: instructions array")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251124151515.2543403-1-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Anton Protopopov 2025-11-24 15:15:15 +00:00 committed by Alexei Starovoitov
parent c427320873
commit fad804002e
1 changed files with 9 additions and 0 deletions
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9
kernel/bpf/verifier.c
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@ -22266,6 +22266,15 @@ static int jit_subprogs(struct bpf_verifier_env *env)
cond_resched();
}
/*
* Cleanup func[i]->aux fields which aren't required
* or can become invalid in future
*/
for (i = 0; i < env->subprog_cnt; i++) {
func[i]->aux->used_maps = NULL;
func[i]->aux->used_map_cnt = 0;
}
/* finally lock prog and jit images for all functions and
* populate kallsysm. Begin at the first subprogram, since
* bpf_prog_load will add the kallsyms for the main program.