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| author | Takashi Iwai <tiwai@suse.de> | 2018-03-06 00:00:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-18 13:15:43 +0300 |
| commit | 6eebd4d9336326afbc7c3e325ee14c85a2651a6a (patch) | |
| tree | fc44c4e6187d626d14db11c76be50c4bbf8c46cc | |
| parent | bbf594868f37cfd50d4289a01a9e25151b9a26cf (diff) | |
| download | linux-6eebd4d9336326afbc7c3e325ee14c85a2651a6a.tar.xz | |
ALSA: seq: Don't allow resizing pool in use
commit d85739367c6d56e475c281945c68fdb05ca74b4c upstream.
This is a fix for a (sort of) fallout in the recent commit
d15d662e89fc ("ALSA: seq: Fix racy pool initializations") for
CVE-2018-1000004.
As the pool resize deletes the existing cells, it may lead to a race
when another thread is writing concurrently, eventually resulting a
UAF.
A simple workaround is not to allow the pool resizing when the pool is
in use. It's an invalid behavior in anyway.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/core/seq/seq_clientmgr.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index dee6691013c1..99486e1eeec4 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -1929,6 +1929,9 @@ static int snd_seq_ioctl_set_client_pool(struct snd_seq_client *client, (! snd_seq_write_pool_allocated(client) || info.output_pool != client->pool->size)) { if (snd_seq_write_pool_allocated(client)) { + /* is the pool in use? */ + if (atomic_read(&client->pool->counter)) + return -EBUSY; /* remove all existing cells */ snd_seq_pool_mark_closing(client->pool); snd_seq_queue_client_leave_cells(client->number); |