linux-kernel - [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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <db47108d-3967-6760-3de2-17bf60741bc2@gmail.com>
Date:   Tue, 17 Dec 2019 21:24:21 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     perex@...ex.cz, tiwai@...e.com, rfontana@...hat.com,
        gregkh@...uxfoundation.org, allison@...utok.net, tglx@...utronix.de
Cc:     alsa-devel@...a-project.org, LKML <linux-kernel@...r.kernel.org>
Subject: [BUG] ALSA: seq: a possible sleep-in-atomic-context bug in
 snd_virmidi_dev_receive_event()

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.


Best wishes,
Jia-Ju Bai