Smatch complains that "count" isn't clamped properly and "oxfw->dev_lock_changed" is false then it leads to an information leak. But it turns out that "oxfw->dev_lock_changed" is always set and the condition can be removed.

Signed-off-by: Dan Carpenter dan.carpenter@oracle.com --- v2: this version just removes the condition

sound/firewire/oxfw/oxfw-hwdep.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/sound/firewire/oxfw/oxfw-hwdep.c b/sound/firewire/oxfw/oxfw-hwdep.c index 9e1b3e151bad..a0fe99618554 100644 --- a/sound/firewire/oxfw/oxfw-hwdep.c +++ b/sound/firewire/oxfw/oxfw-hwdep.c @@ -35,13 +35,11 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, }

memset(&event, 0, sizeof(event)); - if (oxfw->dev_lock_changed) { - event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS; - event.lock_status.status = (oxfw->dev_lock_count > 0); - oxfw->dev_lock_changed = false; + event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS; + event.lock_status.status = (oxfw->dev_lock_count > 0); + oxfw->dev_lock_changed = false;

- count = min_t(long, count, sizeof(event.lock_status)); - } + count = min_t(long, count, sizeof(event.lock_status));

spin_unlock_irq(&oxfw->lock);

Hi,

On Mon, Jan 25, 2021 at 02:13:44PM +0300, Dan Carpenter wrote:

Smatch complains that "count" is not clamped when "ff->dev_lock_changed" and it leads to an information leak. Fortunately, that's not actually possible and the condition can be deleted.

Signed-off-by: Dan Carpenter dan.carpenter@oracle.com

v2: just delet the condition

sound/firewire/fireface/ff-hwdep.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)

Acked-by: Takashi Sakamoto o-takashi@sakamocchi.jp

ALSA firewire stack includes some drivers. Although some of them implement unique event as well as the lock event, the others supports the lock event only. The condition statement comes from the former, I guess. ALSA BeBoB, OXFW, and Fireface drivers are the latter. Later I'll post the similar patch for ALSA BeBoB driver.

Anyway, thank you to find the issue ;)

diff --git a/sound/firewire/fireface/ff-hwdep.c b/sound/firewire/fireface/ff-hwdep.c index 4b2e0dff5ddb..ea64a2a41eea 100644 --- a/sound/firewire/fireface/ff-hwdep.c +++ b/sound/firewire/fireface/ff-hwdep.c @@ -35,13 +35,11 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, }

memset(&event, 0, sizeof(event));

• 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;
  

• 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));
  

• }

• count = min_t(long, count, sizeof(event.lock_status));

  spin_unlock_irq(&ff->lock);

-- 2.29.2

Thanks

Takashi Sakamoto