hdlcdrv: Fix divide by zero in hdlcdrv_ioctl
authorFiro Yang <firogm@gmail.com>
Fri, 26 May 2017 14:37:38 +0000 (22:37 +0800)
committerDavid S. Miller <davem@davemloft.net>
Sat, 27 May 2017 22:44:17 +0000 (18:44 -0400)
syszkaller fuzzer triggered a divide by zero, when set calibration
through ioctl().

To fix it, test 'bitrate' if it is negative or 0, just return -EINVAL.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Firo Yang <firogm@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/hamradio/hdlcdrv.c

index 8c3633c1d0789718fc528b9873e8295e6ab6b09e..97e3bc60c3e7d111184f4c60ce4afe50757d1398 100644 (file)
@@ -576,6 +576,8 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
        case HDLCDRVCTL_CALIBRATE:
                if(!capable(CAP_SYS_RAWIO))
                        return -EPERM;
+               if (s->par.bitrate <= 0)
+                       return -EINVAL;
                if (bi.data.calibrate > INT_MAX / s->par.bitrate)
                        return -EINVAL;
                s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;