sound: oss/sb_audio: prevent divide by zero bug

Speed comes from get_user() in audio_ioctl().  We use it to set the "s"
variable before clamping it to valid values so it could lead to a divide
by zero bug.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 3 insertions, 1 deletions

diff --git a/sound/oss/sb_audio.c b/sound/oss/sb_audio.c
index 733b014ec7d1..b2b3c014221a 100644
--- a/sound/oss/sb_audio.c
+++ b/sound/oss/sb_audio.c
@@ -575,13 +575,15 @@ static int jazz16_audio_set_speed(int dev, int speed)
         if (speed > 0)
         {
                 int tmp;
-                int s = speed * devc->channels;
+                int s;
 
                 if (speed < 5000)
                         speed = 5000;
                 if (speed > 44100)
                         speed = 44100;
 
+                s = speed * devc->channels;
+
                 devc->tconst = (256 - ((1000000 + s / 2) / s)) & 0xff;
 
                 tmp = 256 - devc->tconst;