* [PATCH bpf-next] bpf: Remove unnecessary CAP_MAC_ADMIN check
@ 2020-03-05 20:49 KP Singh
2020-03-05 22:38 ` Alexei Starovoitov
0 siblings, 1 reply; 2+ messages in thread
From: KP Singh @ 2020-03-05 20:49 UTC (permalink / raw)
To: linux-security-module, linux-kernel, bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Paul Turner, Jann Horn,
Stephen Smalley, Florent Revest, Brendan Jackman
From: KP Singh <kpsingh@google.com>
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>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] bpf: Remove unnecessary CAP_MAC_ADMIN check
2020-03-05 20:49 [PATCH bpf-next] bpf: Remove unnecessary CAP_MAC_ADMIN check KP Singh
@ 2020-03-05 22:38 ` Alexei Starovoitov
0 siblings, 0 replies; 2+ messages in thread
From: Alexei Starovoitov @ 2020-03-05 22:38 UTC (permalink / raw)
To: KP Singh
Cc: linux-security-module, linux-kernel, bpf, Alexei Starovoitov,
Daniel Borkmann, Paul Turner, Jann Horn, Stephen Smalley,
Florent Revest, Brendan Jackman
On Thu, Mar 05, 2020 at 09:49:55PM +0100, KP Singh wrote:
> From: KP Singh <kpsingh@google.com>
>
> 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>
Applied. Thanks
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-03-05 22:39 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-05 20:49 [PATCH bpf-next] bpf: Remove unnecessary CAP_MAC_ADMIN check KP Singh
2020-03-05 22:38 ` Alexei Starovoitov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).