From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CF478F57 for ; Sun, 16 Jul 2023 20:53:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3552C433C8; Sun, 16 Jul 2023 20:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689540838; bh=jyu/2z3GOz66/g5JjtY+EJGwaqKE46Nu7bzLLPwXOOQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cKlB4HCFdNqbGktTlgKcZnkyC5hP56r/YgfInZwUVbc44nmUOgB/3JeADi6UA/wEq 2fmxM3yfK/S5jlBNytKEq9GoVXNJFAJ2xtpK2MyaZe5okb1mdBrGcOKBDbMIJWXk4c AJlPdly+3FwZsiJFh74S0gEHdhyy98VLFIQG77vA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Amir Goldstein , Christian Brauner , Jan Kara , Sasha Levin Subject: [PATCH 6.1 506/591] fanotify: disallow mount/sb marks on kernel internal pseudo fs Date: Sun, 16 Jul 2023 21:50:45 +0200 Message-ID: <20230716194936.979610263@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194923.861634455@linuxfoundation.org> References: <20230716194923.861634455@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Amir Goldstein [ Upstream commit 69562eb0bd3e6bb8e522a7b254334e0fb30dff0c ] Hopefully, nobody is trying to abuse mount/sb marks for watching all anonymous pipes/inodes. I cannot think of a good reason to allow this - it looks like an oversight that dated back to the original fanotify API. Link: https://lore.kernel.org/linux-fsdevel/20230628101132.kvchg544mczxv2pm@quack3/ Fixes: 0ff21db9fcc3 ("fanotify: hooks the fanotify_mark syscall to the vfsmount code") Signed-off-by: Amir Goldstein Reviewed-by: Christian Brauner Signed-off-by: Jan Kara Message-Id: <20230629042044.25723-1-amir73il@gmail.com> Signed-off-by: Sasha Levin --- fs/notify/fanotify/fanotify_user.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 4546da4a54f95..9df5db0f10ff2 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1574,6 +1574,20 @@ static int fanotify_events_supported(struct fsnotify_group *group, path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM) return -EINVAL; + /* + * mount and sb marks are not allowed on kernel internal pseudo fs, + * like pipe_mnt, because that would subscribe to events on all the + * anonynous pipes in the system. + * + * SB_NOUSER covers all of the internal pseudo fs whose objects are not + * exposed to user's mount namespace, but there are other SB_KERNMOUNT + * fs, like nsfs, debugfs, for which the value of allowing sb and mount + * mark is questionable. For now we leave them alone. + */ + if (mark_type != FAN_MARK_INODE && + path->mnt->mnt_sb->s_flags & SB_NOUSER) + return -EINVAL; + /* * We shouldn't have allowed setting dirent events and the directory * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode, -- 2.39.2