master: sys/dev/sound/pcm/vchan.c cb8ff21ad49e7a92c572b31c6e26ad74d0feed5f

Tue Dec 2 18:56:46 PST 2008

YONETANI Tomokazu wrote:
On Mon, Dec 01, 2008 at 03:59:30PM -0800, Simon Schubert wrote:
http://gitweb.dragonflybsd.org/?p=dragonfly.git;a=commitdiff;h=cb8ff21ad49e7a92c572b31c6e26ad74d0feed5f
  -       scale = (volume << 16) / 100;
  +       scale = log_mix_cvt[volume];
I don't see how it's guaranteed that (volume < countof(log_mix_cvt) - 1).
The comment above that says `volume is in range 0-100', which is only
satisfied when (ch->volume & 0xff) + ((ch->volume >> 8) & 0xff) <= 200,
but I see no such check in the code under /sys/dev/sound...
I believe that the mixer ioctls check for overflow.  Otherwise this is a bug.

cheers
  simon
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