From: bot+bpf-ci@kernel.org
To: utilityemal77@gmail.com,ast@kernel.org,daniel@iogearbox.net,andrii@kernel.org,kpsingh@kernel.org,matt@bobrowski.net,paul@paul-moore.com,mic@digikod.net,viro@zeniv.linux.org.uk,brauner@kernel.org,kees@kernel.org
Cc: casey@schaufler-ca.com,gnoack@google.com,jack@suse.cz,song@kernel.org,yonghong.song@linux.dev,martin.lau@linux.dev,eddyz87@gmail.com,memxor@gmail.com,jolsa@kernel.org,m@maowtm.org,bpf@vger.kernel.org,linux-security-module@vger.kernel.org,linux-kernel@vger.kernel.org,utilityemal77@gmail.com,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,mason@kernel.org,ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf-next v3 05/15] lsm: Add the bpf_lsm_policy_from_fd kfunc
Date: Wed, 9 Sep 2026 20:46:25 +0000 (UTC) [thread overview]
Message-ID: <6e6ef0d3fdf6d830cea306c9547312ad33593c979764afabc5f37765d5206183@mail.kernel.org> (raw)
In-Reply-To: <20260909193719.518517-6-utilityemal77@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 2481 bytes --]
> diff --git a/security/bpf_lsm_kfuncs.c b/security/bpf_lsm_kfuncs.c
> index e1190215d477..988dcd6f4dd9 100644
> --- a/security/bpf_lsm_kfuncs.c
> +++ b/security/bpf_lsm_kfuncs.c
[ ... ]
> @@ -14,11 +14,50 @@
>
> __bpf_kfunc_start_defs();
>
> +/**
> + * bpf_lsm_policy_from_fd - Get an LSM policy object from a fd
> + * @fd: file descriptor referring to a policy object, resolved in the
> + * file descriptor table of the task running the program
> + * @flags: reserved for future use, must be 0
> + *
> + * Translate @fd, as set up through the owning LSM's own userspace
> + * interface, into a referenced policy object. The fd identifies the
> + * LSM asked to translate it: each LSM recognizes its own fds and
> + * declines every other. Only syscall programs may call this kfunc:
> + * they run in the context of the task invoking them, where the fd is
> + * meaningful. The reference must be released with
> + * bpf_lsm_policy_release().
> + *
> + * Return: A referenced policy object, or NULL if @flags is not 0, if
> + * no enabled LSM recognizes @fd as one of its policy objects, or if
> + * the recognizing LSM fails to translate it.
> + */
> +__bpf_kfunc struct lsm_policy_object *bpf_lsm_policy_from_fd(int fd, u32 flags)
> +{
> + struct lsm_static_call *scall;
> + struct lsm_policy_object *object;
> + int err;
> +
> + if (flags)
> + return NULL;
> +
> + lsm_for_each_hook(scall, policy_object_from_fd) {
> + err = scall->hl->hook.policy_object_from_fd(fd, &object);
> + if (err == -EOPNOTSUPP)
> + /* Not this LSM's fd: let another claim it. */
> + continue;
> + if (err)
> + return NULL;
> + return object;
> + }
> + return NULL;
> +}
> +
> /**
> * bpf_lsm_policy_release - Release a policy object reference
> * @object: policy object to release
> *
> - * Release an acquired reference on a policy object.
> + * Release a reference acquired with bpf_lsm_policy_from_fd().
> */
This isn't a bug, but would keeping the more general wording here
('Release an acquired reference on a policy object') age better than
listing the acquiring kfuncs? A reference can also come out of a map kptr
field via bpf_kptr_xchg(), so the comment might need amending again when
other acquiring kfuncs are added.
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/34398515657
next prev parent reply other threads:[~2026-09-09 20:46 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 19:37 [PATCH bpf-next v3 00/15] BPF interface for applying Landlock rulesets Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 01/15] lsm: Add the LSM policy object lifetime hooks Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 02/15] lsm: Add the bprm_apply_policy_object LSM hook Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 03/15] lsm: Move the lsm_for_each_hook() macro to security/lsm.h Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 04/15] lsm: Add the bpf_lsm_policy_release kfunc and policy object destructor Justin Suess
2026-09-09 20:29 ` bot+bpf-ci
2026-09-09 21:34 ` Paul Moore
2026-09-09 22:20 ` Justin Suess
2026-09-09 23:08 ` Paul Moore
2026-09-12 3:37 ` Alexei Starovoitov
2026-09-12 5:26 ` Justin Suess
2026-09-12 19:33 ` Alexei Starovoitov
2026-09-13 19:41 ` Paul Moore
2026-09-09 19:37 ` [PATCH bpf-next v3 05/15] lsm: Add the bpf_lsm_policy_from_fd kfunc Justin Suess
2026-09-09 20:46 ` bot+bpf-ci [this message]
2026-09-09 19:37 ` [PATCH bpf-next v3 06/15] lsm: Add the bpf_lsm_policy_acquire kfunc Justin Suess
2026-09-09 20:30 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 07/15] lsm: Add the bpf_lsm_policy_apply_bprm kfunc Justin Suess
[not found] ` <20260909195500.DA3E31F000FF@smtp.kernel.org>
2026-09-09 20:20 ` Justin Suess
2026-09-12 3:38 ` Alexei Starovoitov
2026-09-12 5:39 ` Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 08/15] lsm: Document the LSM policy object interface Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 09/15] selftests/bpf: Add tests for the LSM policy object kfuncs Justin Suess
2026-09-09 20:30 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 10/15] landlock: Expose the ruleset fd lookup to the rest of Landlock Justin Suess
2026-09-09 19:37 ` [PATCH bpf-next v3 11/15] landlock: Factor the credential restriction out of landlock_restrict_self() Justin Suess
2026-09-09 20:29 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 12/15] landlock: Free rulesets after an RCU grace period Justin Suess
2026-09-09 20:46 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 13/15] landlock: Implement the LSM policy object hooks Justin Suess
2026-09-09 20:46 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 14/15] selftests/bpf: Test the LSM policy object kfuncs with Landlock Justin Suess
2026-09-09 20:46 ` bot+bpf-ci
2026-09-09 19:37 ` [PATCH bpf-next v3 15/15] landlock: Document the BPF policy interface Justin Suess
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