bpf: Fix ksock build with BPF_LSM=y and SECURITY_NETWORK=n

bpf_ksock.c references bpf_lsm_socket_sendmsg() whenever
CONFIG_BPF_LSM=y, but the socket LSM hooks, and with them the BPF LSM
socket_sendmsg hook, only exist with CONFIG_SECURITY_NETWORK=y. Without
it resolve_btfids warns:

  WARN: resolve_btfids: unresolved symbol bpf_lsm_socket_sendmsg

and since commit 201a454df948 ("resolve_btfids: Fix the --fatal_warnings
exit status") that fails the build with CONFIG_WERROR=y.

Only reference the hook with CONFIG_SECURITY_NETWORK=y, and use
BTF_ID_UNUSED otherwise. The ID stays zero, as it was when unresolved,
so bpf_ksock_kfunc_filter() keeps allowing LSM programs: none can be
attached to socket_sendmsg without CONFIG_SECURITY_NETWORK.

Fixes: 7ae4eb14c5f9 ("bpf: Add ksock kfuncs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Mahe Tardy <mahe.tardy@gmail.com>
Link: https://patch.msgid.link/20261019211006.2574350-4-sashal@kernel.org

0 files changed, 0 insertions, 0 deletions