[PATCH] ALSA: pcm: oss: Avoid plugin buffer overflow

[Takashi Iwai]

On Thu, 30 Apr 2020 18:34:02 +0200,
Serge Belyshev wrote:
> 
> > ...
> >
> > This patch addresses those possible buffer overflow accesses by simply
> > setting the upper limit per the given buffer size for each plugin
> > before src_frames() and after dst_frames() calls.
> 
> Hi!
> 
> This patch breaks any output via oss interface, as evident by "mpv
> --ao=oss somefile.mp3" or "mpg123 -o oss somefile.mp3" or just "cat
> /dev/urandom > /dev/dsp", which worked previously in kernel version 5.5
> but not any longer starting with 5.6.
> 
> It appears here that plugin->buf_frames is zero which results in ENXIO
> returned to userspace.

The fix is already in sound git tree, and will be in the next pull
request to 5.7-rc4.


thanks,

Takashi