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Date: Sun, 18 Feb 2024 20:12:56 +0100
From: Pavel Machek <pavel@denx.de>
To: Sasha Levin <sashal@kernel.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Kees Cook <keescook@chromium.org>,
	Kentaro Takeda <takedakn@nttdata.co.jp>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	Eric Biederman <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, mingo@redhat.com,
	peterz@infradead.org, juri.lelli@redhat.com,
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	michael.christie@oracle.com, mst@redhat.com, mjguzik@gmail.com,
	npiggin@gmail.com, zhangpeng.00@bytedance.com, hca@linux.ibm.com
Subject: Re: [PATCH AUTOSEL 5.10 7/8] exec: Distinguish in_execve from in_exec
Message-ID: <ZdJWuMifIiNnrLbZ@duo.ucw.cz>
References: <20240202184156.541981-1-sashal@kernel.org>
 <20240202184156.541981-7-sashal@kernel.org>
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Hi!

> From: Kees Cook <keescook@chromium.org>
>=20
> [ Upstream commit 90383cc07895183c75a0db2460301c2ffd912359 ]
>=20
> Just to help distinguish the fs->in_exec flag from the current->in_execve
> flag, add comments in check_unsafe_exec() and copy_fs() for more
> context. Also note that in_execve is only used by TOMOYO now.

These are just a whitespace changes, we should not need them.

Best regards,
								Pavel

> +++ b/fs/exec.c
> @@ -1565,6 +1565,7 @@ static void check_unsafe_exec(struct linux_binprm *=
bprm)
>  	}
>  	rcu_read_unlock();
> =20
> +	/* "users" and "in_exec" locked for copy_fs() */
>  	if (p->fs->users > n_fs)
>  		bprm->unsafe |=3D LSM_UNSAFE_SHARE;
>  	else
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index aa015416c569..65cfe85de8d5 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -806,7 +806,7 @@ struct task_struct {
>  	 */
>  	unsigned			sched_remote_wakeup:1;
> =20
> -	/* Bit to tell LSMs we're in execve(): */
> +	/* Bit to tell TOMOYO we're in execve(): */
>  	unsigned			in_execve:1;
>  	unsigned			in_iowait:1;
>  #ifndef TIF_RESTORE_SIGMASK
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 633b0af1d1a7..906dbaf25058 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1452,6 +1452,7 @@ static int copy_fs(unsigned long clone_flags, struc=
t task_struct *tsk)
>  	if (clone_flags & CLONE_FS) {
>  		/* tsk->fs is already what we want */
>  		spin_lock(&fs->lock);
> +		/* "users" and "in_exec" locked for check_unsafe_exec() */
>  		if (fs->in_exec) {
>  			spin_unlock(&fs->lock);
>  			return -EAGAIN;

--=20
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