From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Thu, 21 Jan 2021 06:10:47 +0000 Subject: [PATCH] ALSA: fireface: fix info leak in hwdep_read() Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Clemens Ladisch Cc: alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org, Takashi Iwai , Mark Brown If "ff->dev_lock_changed" has not changed and "count" is too large then this will copy data beyond the end of the struct to user space. Fixes: f656edd5fb33 ("ALSA: fireface: add hwdep interface") Signed-off-by: Dan Carpenter --- sound/firewire/fireface/ff-hwdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/firewire/fireface/ff-hwdep.c b/sound/firewire/fireface/ff-hwdep.c index 4b2e0dff5ddb..b84dde609a03 100644 --- a/sound/firewire/fireface/ff-hwdep.c +++ b/sound/firewire/fireface/ff-hwdep.c @@ -35,12 +35,12 @@ static long 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 (ff->dev_lock_changed) { event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS; event.lock_status.status = (ff->dev_lock_count > 0); ff->dev_lock_changed = false; - count = min_t(long, count, sizeof(event.lock_status)); } spin_unlock_irq(&ff->lock); -- 2.29.2