bpf: Fix race between bpf_map_new_fd() and close_fd()

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Because there is time gap between bpf_map_new_fd() and close_fd(), a
concurrent thread is able to close the new fd and opens a new, unrelated
file with the exact same fd number. Thereafter, this close_fd() might
inadvertently close the unrelated file.

To avoid such regression, do finalize log before security_bpf_map_create().

However, in order to achieve it, move bpf_get_file_flag(),
security_bpf_map_create(), bpf_map_alloc_id(), and bpf_map_new_fd() from
__map_create() to map_create(). And, rename __map_create() to
map_create_alloc() meanwhile.

Then, in order to reuse the map and token when all checks pass in
map_create_alloc(), pass "struct bpf_map **" and "struct bpf_token **" to
map_create_alloc().

Fixes: 49f9b2b2a1 ("bpf: Add syscall common attributes support for map_create")
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260521142909.95818-1-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Leon Hwang 2026-05-21 22:29:09 +08:00 • committed by Alexei Starovoitov

parent 7f9ce282da

commit 9b435d23f5

1 changed files with 47 additions and 33 deletions

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kernel/bpf/syscall.c

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