From: Nicolai Stange <nstange@suse.de>
To: Takashi Iwai <tiwai@suse.de>
Cc: alsa-devel@alsa-project.org, "Miroslav Benes" <mbenes@suse.cz>,
范龙飞 <long7573@126.com>, "Nicolai Stange" <nstange@suse.de>
Subject: Re: [PATCH 2/2] ALSA: seq: More protection for concurrent write and ioctl races
Date: Thu, 08 Mar 2018 11:38:30 +0100 [thread overview]
Message-ID: <87371akg2h.fsf@suse.de> (raw)
In-Reply-To: <20180308071856.12149-3-tiwai@suse.de> (Takashi Iwai's message of "Thu, 8 Mar 2018 08:18:56 +0100")
Takashi Iwai <tiwai@suse.de> writes:
> This patch is an attempt for further hardening against races between
> the concurrent write and ioctls. The previous fix d15d662e89fc
> ("ALSA: seq: Fix racy pool initializations") covered the race of the
> pool initialization at writer and the pool resize ioctl by the
> client->ioctl_mutex (CVE-2018-1000004). However, basically this mutex
> should be applied more widely to the whole write operation for
> avoiding the unexpected pool operations by another thread.
>
> The only change outside snd_seq_write() is the additional mutex
> argument to helper functions, so that we can unlock / relock the given
> mutex temporarily during schedule() call for blocking write.
>
> Fixes: d15d662e89fc ("ALSA: seq: Fix racy pool initializations")
> Reported-by: 范龙飞 <long7573@126.com>
> Reported-by: Nicolai Stange <nstange@suse.de>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
Reviewed-and-tested-by: Nicolai Stange <nstange@suse.de>
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prev parent reply other threads:[~2018-03-08 10:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-08 7:18 [PATCH 0/2] More hardening for ALSA sequencer write/ioctl races Takashi Iwai
2018-03-08 7:18 ` [PATCH 1/2] ALSA: seq: Don't allow resizing pool in use Takashi Iwai
2018-03-08 10:44 ` Nicolai Stange
2018-03-08 10:56 ` Takashi Iwai
2018-03-08 7:18 ` [PATCH 2/2] ALSA: seq: More protection for concurrent write and ioctl races Takashi Iwai
2018-03-08 10:38 ` Nicolai Stange [this message]
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