From: Jaroslav Kysela <perex@perex.cz>
To: Takashi Iwai <tiwai@suse.de>, alsa-devel@alsa-project.org
Cc: linux-kernel@vger.kernel.org, Clement Lecigne <clecigne@google.com>
Subject: Re: [PATCH] ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF
Date: Fri, 13 Jan 2023 13:44:45 +0100 [thread overview]
Message-ID: <abe92f46-d4d7-4d9d-82b3-d8c9e7e26181@perex.cz> (raw)
In-Reply-To: <20230113120745.25464-1-tiwai@suse.de>
On 13. 01. 23 13:07, Takashi Iwai wrote:
> From: Clement Lecigne <clecigne@google.com>
>
> Takes rwsem lock inside snd_ctl_elem_read instead of snd_ctl_elem_read_user
> like it was done for write in commit 1fa4445f9adf1 ("ALSA: control - introduce
> snd_ctl_notify_one() helper"). Doing this way we are also fixing the following
> locking issue happening in the compat path which can be easily triggered and
> turned into an use-after-free.
>
> 64-bits:
> snd_ctl_ioctl
> snd_ctl_elem_read_user
> [takes controls_rwsem]
> snd_ctl_elem_read [lock properly held, all good]
> [drops controls_rwsem]
>
> 32-bits:
> snd_ctl_ioctl_compat
> snd_ctl_elem_write_read_compat
> ctl_elem_write_read
> snd_ctl_elem_read [missing lock, not good]
>
> CVE-2023-0266 was assigned for this issue.
>
> Cc: stable@kernel.org # 5.13+
> Signed-off-by: Clement Lecigne <clecigne@google.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
--
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
prev parent reply other threads:[~2023-01-13 12:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 12:07 [PATCH] ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF Takashi Iwai
2023-01-13 12:44 ` Jaroslav Kysela [this message]
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