linux-kernel - Re: [PATCH 3/4] TTY: pty, release tty in all ptmx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <201110121523.05567.arnd@arndb.de>
Date:	Wed, 12 Oct 2011 15:23:05 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Jiri Slaby <jslaby@...e.cz>
Cc:	gregkh@...e.de, linux-kernel@...r.kernel.org, jirislaby@...il.com,
	stable@...nel.org, Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [PATCH 3/4] TTY: pty, release tty in all ptmx_open fail paths

On Wednesday 12 October 2011, Jiri Slaby wrote:
> Mistakenly, commit 64ba3dc3143d (tty: never hold BTM while getting
> tty_mutex) switched one fail path in ptmx_open to not free the newly
> allocated tty.
> 
> Fix that by jumping to the appropriate place. And rename the labels so
> that it's clear what is going on there.
> 
> Introduced-in: v2.6.36-rc2
> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> Cc: stable@...nel.org
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Alan Cox <alan@...rguk.ukuu.org.uk>
> Cc: Greg Kroah-Hartman <gregkh@...e.de>

Ok, I have checked that this patch returns the code into the state
before my broken patch, that looks good.

I think I made the same mistake trying to understand your patch
that I made originally when I introduced the bug, which was to
confuse the lifetime of the pty master with the lifetime of the
slave device, so I thought that tty_release should not be called
if we never called ptm_driver->ops->open(), but that's actually
a different device.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/