Re: [PATCH v2] selinux: various sparse fixes

From: Ondrej Mosnacek <omosnace@redhat.com>
To: Paul Moore <paul@paul-moore.com>
Cc: SElinux list <selinux@vger.kernel.org>
Subject: Re: [PATCH v2] selinux: various sparse fixes
Date: Thu, 27 Jan 2022 20:02:49 +0100	[thread overview]
Message-ID: <CAFqZXNv9LhVWD_cK+TbgnPSRnVSndecqJOh2vwqTVkxOQdu0zw@mail.gmail.com> (raw)
In-Reply-To: <164330771809.139041.6643670399086580972.stgit@olly>

On Thu, Jan 27, 2022 at 7:22 PM Paul Moore <paul@paul-moore.com> wrote:
> When running the SELinux code through sparse, there are a handful of
> warnings.  This patch resolves some of these warnings caused by
> "__rcu" mismatches.
>
>  % make W=1 C=1 security/selinux/
>
> Signed-off-by: Paul Moore <paul@paul-moore.com>
> ---
>  security/selinux/hooks.c   |    6 +++---
>  security/selinux/ibpkey.c  |    2 +-
>  security/selinux/netnode.c |    5 +++--
>  security/selinux/netport.c |    2 +-
>  4 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 221e642025f5..0e857f86f5a7 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2534,7 +2534,7 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
>         if (rc) {
>                 clear_itimer();
>
> -               spin_lock_irq(&current->sighand->siglock);
> +               spin_lock_irq(unrcu_pointer(&current->sighand->siglock));
>                 if (!fatal_signal_pending(current)) {
>                         flush_sigqueue(&current->pending);
>                         flush_sigqueue(&current->signal->shared_pending);
> @@ -2542,13 +2542,13 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
>                         sigemptyset(&current->blocked);
>                         recalc_sigpending();
>                 }
> -               spin_unlock_irq(&current->sighand->siglock);
> +               spin_unlock_irq(unrcu_pointer(&current->sighand->siglock));

Shouldn't this be:

spin_[un]lock_irq(&unrcu_pointer(current->sighand)->siglock);

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.