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| author | Takashi Iwai <tiwai@suse.de> | 2020-08-04 20:58:15 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-08-11 15:32:31 +0200 |
| commit | 34f41d924fc8d5c482a95214581f0b5ede308ce9 (patch) | |
| tree | d8d174b19e8ad1bcb1b0283a2d962e12e2c9cb41 /sound | |
| parent | 21e7fc3f69daa0fd2974edcaa02590c1df81889f (diff) | |
| download | linux-stable-34f41d924fc8d5c482a95214581f0b5ede308ce9.tar.gz linux-stable-34f41d924fc8d5c482a95214581f0b5ede308ce9.tar.bz2 linux-stable-34f41d924fc8d5c482a95214581f0b5ede308ce9.zip | |
ALSA: seq: oss: Serialize ioctls
commit 80982c7e834e5d4e325b6ce33757012ecafdf0bb upstream.
Some ioctls via OSS sequencer API may race and lead to UAF when the
port create and delete are performed concurrently, as spotted by a
couple of syzkaller cases. This patch is an attempt to address it by
serializing the ioctls with the existing register_mutex.
Basically OSS sequencer API is an obsoleted interface and was designed
without much consideration of the concurrency. There are very few
applications with it, and the concurrent performance isn't asked,
hence this "big hammer" approach should be good enough.
Reported-by: syzbot+1a54a94bd32716796edd@syzkaller.appspotmail.com
Reported-by: syzbot+9d2abfef257f3e2d4713@syzkaller.appspotmail.com
Suggested-by: Hillf Danton <hdanton@sina.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200804185815.2453-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/core/seq/oss/seq_oss.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/sound/core/seq/oss/seq_oss.c b/sound/core/seq/oss/seq_oss.c index e1f44fc86885..ed5bca0db3e7 100644 --- a/sound/core/seq/oss/seq_oss.c +++ b/sound/core/seq/oss/seq_oss.c @@ -181,10 +181,16 @@ static long odev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct seq_oss_devinfo *dp; + long rc; + dp = file->private_data; if (snd_BUG_ON(!dp)) return -ENXIO; - return snd_seq_oss_ioctl(dp, cmd, arg); + + mutex_lock(®ister_mutex); + rc = snd_seq_oss_ioctl(dp, cmd, arg); + mutex_unlock(®ister_mutex); + return rc; } #ifdef CONFIG_COMPAT |