[PATCH bpf-next] bpf: Remove unnecessary CAP_MAC_ADMIN check
From: KP Singh <hidden>
Date: 2020-03-05 20:50:04
Also in:
bpf, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
From: KP Singh <redacted>
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 <redacted>
---
kernel/bpf/verifier.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ae32517d4ccd..55d376c53f7d 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);
--
2.20.1