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| author | Takashi Iwai <tiwai@suse.de> | 2017-10-09 17:05:35 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2017-10-10 13:45:13 +0200 |
| commit | 19b592dae895aad10b84246b0e12caad04e9eb0d (patch) | |
| tree | 7e26bb0aaebe09cdc7b7dc6d0c42b8b2bfef23df /sound/core | |
| parent | a6aa6cdcecfc0eb8a6fe634535384b4a63f38258 (diff) | |
| download | linux-19b592dae895aad10b84246b0e12caad04e9eb0d.tar.bz2 | |
ALSA: seq: Add sanity check for user-space pointer delivery
The sequencer event may contain a user-space pointer with its
SNDRV_SEQ_EXT_USRPTR bit, and we assure that its delivery is limited
with non-atomic mode. Otherwise the copy_from_user() may hit the
fault and cause a problem. Although the core code doesn't set such a
flag (only set at snd_seq_write()), any wild driver may set it
mistakenly and lead to an unexpected crash.
This patch adds a sanity check of such events at the delivery core
code to filter out the invalid invocation in the atomic mode.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/seq/seq_clientmgr.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index ea2d0ae85bd3..f2343f63ba26 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -802,6 +802,10 @@ static int snd_seq_deliver_event(struct snd_seq_client *client, struct snd_seq_e return -EMLINK; } + if (snd_seq_ev_is_variable(event) && + snd_BUG_ON(atomic && (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR))) + return -EINVAL; + if (event->queue == SNDRV_SEQ_ADDRESS_SUBSCRIBERS || event->dest.client == SNDRV_SEQ_ADDRESS_SUBSCRIBERS) result = deliver_to_subscribers(client, event, atomic, hop); |