selftests/bpf: Test forbidden bpf_ksock_send() LSM attach

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The bpf_ksock_send() kfunc eventually calls security_socket_sendmsg(),
thus creating a possible recursion if a program calling the kfunc is
attached on that specific hook. A filter is added on the kfunc
registration to prevent that at load time from the verifier. This test
exercises that the verifier will reject such program on that attach
point.

Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20260813110540.103550-5-mahe.tardy@gmail.com

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Mahe Tardy 2026-08-13 11:05:39 +00:00 • committed by Daniel Borkmann

parent c7838e3dc6

commit 7b0dfbf577

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6

tools/testing/selftests/bpf/prog_tests/ksock.c

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35

tools/testing/selftests/bpf/progs/ksock_lsm_verifier.c

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