On Mon, Jan 18, 2016 at 2:17 PM, Takashi Iwai tiwai@suse.de wrote:
On Mon, 18 Jan 2016 13:59:49 +0100, Dmitry Vyukov wrote:
Hello,
The following program triggers a BUG in snd_ctl_find_numid:
Do I understand correctly that you meant a kernel WARNING with a stack trace as a "BUG"? If so, the patch below should cover it.
Yes, I guess it's just a BUG warning message.
thanks,
Takashi
-- 8< -- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: control: Avoid kernel warnings from tlv ioctl with numid 0
When a TLV ioctl with numid zero is handled, the driver may spew a kernel warning with a stack trace at each call. The check was intended obviously only for a kernel driver, but not for a user interaction. Let's fix it.
This was spotted by syzkaller fuzzer.
Reported-by: Dmitry Vyukov dvyukov@google.com Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de
sound/core/control.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/core/control.c b/sound/core/control.c index 196a6fe100ca..a85d45595d02 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1405,6 +1405,8 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file, return -EFAULT; if (tlv.length < sizeof(unsigned int) * 2) return -EINVAL;
if (!tlv.numid)return -EINVAL; down_read(&card->controls_rwsem); kctl = snd_ctl_find_numid(card, tlv.numid); if (kctl == NULL) {-- 2.7.0