tree 8da56bce19d9e97ccc2f674633ffc1ecffefe9e1
parent 9b3c5a65b7eaf8b6da97e4ddf74fa44be1064248
author Takashi Iwai <tiwai@suse.de> 1575470904 +0100
committer Ben Hutchings <ben@decadent.org.uk> 1581451435 +0000

ALSA: pcm: oss: Avoid potential buffer overflows

commit 4cc8d6505ab82db3357613d36e6c58a297f57f7c upstream.

syzkaller reported an invalid access in PCM OSS read, and this seems
to be an overflow of the internal buffer allocated for a plugin.
Since the rate plugin adjusts its transfer size dynamically, the
calculation for the chained plugin might be bigger than the given
buffer size in some extreme cases, which lead to such an buffer
overflow as caught by KASAN.

Fix it by limiting the max transfer size properly by checking against
the destination size in each plugin transfer callback.

Reported-by: syzbot+f153bde47a62e0b05f83@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20191204144824.17801-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>