bpf: Remove unnecessary CAP_MAC_ADMIN check
While well intentioned, checking CAP_MAC_ADMIN for attaching
BPF_MODIFY_RETURN tracing programs to "security_" functions is not
necessary as tracing BPF programs already require CAP_SYS_ADMIN.
Fixes: 6ba43b761c41 ("bpf: Attachment verification for BPF_MODIFY_RETURN")
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200305204955.31123-1-kpsingh@chromium.org
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ae32517..55d376c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9808,20 +9808,13 @@ static int check_attach_modify_return(struct bpf_verifier_env *env)
struct bpf_prog *prog = env->prog;
unsigned long addr = (unsigned long) prog->aux->trampoline->func.addr;
- if (within_error_injection_list(addr))
- return 0;
-
/* This is expected to be cleaned up in the future with the KRSI effort
* introducing the LSM_HOOK macro for cleaning up lsm_hooks.h.
*/
- if (!strncmp(SECURITY_PREFIX, prog->aux->attach_func_name,
- sizeof(SECURITY_PREFIX) - 1)) {
-
- if (!capable(CAP_MAC_ADMIN))
- return -EPERM;
-
+ if (within_error_injection_list(addr) ||
+ !strncmp(SECURITY_PREFIX, prog->aux->attach_func_name,
+ sizeof(SECURITY_PREFIX) - 1))
return 0;
- }
verbose(env, "fmod_ret attach_btf_id %u (%s) is not modifiable\n",
prog->aux->attach_btf_id, prog->aux->attach_func_name);
