On Wed, 03 Feb 2016 10:41:14 +0100, Takashi Iwai wrote:
On Wed, 03 Feb 2016 10:35:14 +0100, Takashi Iwai wrote:
On Wed, 03 Feb 2016 09:57:50 +0100, Dmitry Vyukov wrote:
Hello,
The following program triggers an out-of-bounds write in snd_rawmidi_kernel_write1 (run in parallel loop). It seems to try to copy -1 bytes (aka 4GB) from user space into kernel smashing all on its way.
What card is /dev/midi3? Please check /proc/asound/cards. Is it MTPAV?
In anyway the patch below should paper over it. But it's still strange that it gets a negative value there. Could you put
WARN_ON(count1 < 0)
before the newly added check?
I tried it locally with virmidi but it didn't appear, so far. Maybe my setup is too slow and has fewer CPUs than yours.
Scratch my previous patch, I could reproduce the issue on a faster machine in my office now :) Will work on it.
Takashi