[PATCH] ALSA: bebob: potential info leak in hwdep_read()

Dan Carpenter dan.carpenter at oracle.com
Wed Oct 7 09:49:28 CEST 2020


The "count" variable needs to be capped on every path so that we don't
copy too much information to the user.

Fixes: 618eabeae711 ("ALSA: bebob: Add hwdep interface")
Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
---
 sound/firewire/bebob/bebob_hwdep.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sound/firewire/bebob/bebob_hwdep.c b/sound/firewire/bebob/bebob_hwdep.c
index 45b740f44c45..c362eb38ab90 100644
--- a/sound/firewire/bebob/bebob_hwdep.c
+++ b/sound/firewire/bebob/bebob_hwdep.c
@@ -36,12 +36,11 @@ hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
 	}
 
 	memset(&event, 0, sizeof(event));
+	count = min_t(long, count, sizeof(event.lock_status));
 	if (bebob->dev_lock_changed) {
 		event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
 		event.lock_status.status = (bebob->dev_lock_count > 0);
 		bebob->dev_lock_changed = false;
-
-		count = min_t(long, count, sizeof(event.lock_status));
 	}
 
 	spin_unlock_irq(&bebob->lock);
-- 
2.28.0



More information about the Alsa-devel mailing list