From: Al Viro <viro@zeniv.linux.org.uk>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/2] proc: Protect readers of /proc/mounts from remount
Date: Tue, 11 Dec 2018 18:37:11 +0000 [thread overview]
Message-ID: <20181211183711.GG2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20181211183619.GF2217@ZenIV.linux.org.uk>
On Tue, Dec 11, 2018 at 06:36:19PM +0000, Al Viro wrote:
> On Tue, Dec 11, 2018 at 06:24:23PM +0100, Jan Kara wrote:
> > Readers of /proc/mounts (and similar files) are currently unprotected
> > from concurrently running remount on the filesystem they are reporting.
> > This can not only result in bogus reported information but also in
> > confusion in filesystems ->show_options callbacks resulting in
> > use-after-free issues or similar (for example ext4 handling of quota
> > file names is prone to such races).
> >
> > Fix the problem by protecting showing of mount information with
> > sb->s_umount semaphore.
>
> Umm... Which tree is it against and what exactly does your hold_sb() do?
D'oh... I need more coffee. Nevermind.
next prev parent reply other threads:[~2018-12-11 18:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 17:24 [PATCH 0/2 RESEND] vfs: Fix crashes when reading /proc/mounts Jan Kara
2018-12-11 17:24 ` [PATCH 1/2] vfs: Provide function to grab superblock reference Jan Kara
2018-12-11 17:24 ` [PATCH 2/2] proc: Protect readers of /proc/mounts from remount Jan Kara
2018-12-11 18:36 ` Al Viro
2018-12-11 18:37 ` Al Viro [this message]
2018-12-11 18:58 ` Al Viro
2018-12-11 19:14 ` Al Viro
2018-12-12 12:56 ` Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2018-12-18 13:46 [PATCH 0/2 v2] vfs: Fix crashes when reading /proc/mounts Jan Kara
2018-12-18 13:46 ` [PATCH 2/2] proc: Protect readers of /proc/mounts from remount Jan Kara
2018-10-18 13:17 [PATCH 0/2] vfs: Fix crashes when reading /proc/mounts Jan Kara
2018-10-18 13:17 ` [PATCH 2/2] proc: Protect readers of /proc/mounts from remount Jan Kara
2018-10-18 13:17 ` Jan Kara
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