linux-kernel - Re: [BUG] ALSA: seq: a possible sleep-in-atomic-context bug in snd_virmidi_dev_receive

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20191217133045.GA3362771@kroah.com>
Date:   Tue, 17 Dec 2019 14:30:45 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     perex@...ex.cz, tiwai@...e.com, rfontana@...hat.com,
        allison@...utok.net, tglx@...utronix.de,
        alsa-devel@...a-project.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] ALSA: seq: a possible sleep-in-atomic-context bug in
 snd_virmidi_dev_receive_event()

On Tue, Dec 17, 2019 at 09:24:21PM +0800, Jia-Ju Bai wrote:
> The driver may sleep while holding a read lock.
> The function call path (from bottom to top) in Linux 4.19 is:
> 
> sound/core/seq/seq_memory.c, 96:
>     copy_from_user in snd_seq_dump_var_event
> sound/core/seq/seq_virmidi.c, 97:
>     snd_seq_dump_var_event in snd_virmidi_dev_receive_event
> sound/core/seq/seq_virmidi.c, 88:
>     _raw_read_lock in snd_virmidi_dev_receive_event
> 
> copy_from_user() can sleep at runtime.
> 
> I am not sure how to properly fix this possible bug, so I only report it.
> 
> This bug is found by a static analysis tool STCheck written by myself.

Patches for this is usually best :)