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 --- sound/core/seq/seq_clientmgr.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index 6c9cba2166d9..84759d9c54bf 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);