drivers/net/hamradio: Integer overflow in hdlcdrv_ioctl()

The local variable 'bi' comes from userspace. If userspace passed a
large number to 'bi.data.calibrate', there would be an integer overflow
in the following line:
	s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;

Signed-off-by: Wenliang Fan <fanwlexca@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c
index 3169252613faae400904201fa5ad9f1a7decf1cf..5d78c1d08abd60fcc6bcee5dea5ab178a2a166da 100644 (file)
--- a/drivers/net/hamradio/hdlcdrv.c
+++ b/drivers/net/hamradio/hdlcdrv.c
@@ -571,6 +571,8 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
        case HDLCDRVCTL_CALIBRATE:
                if(!capable(CAP_SYS_RAWIO))
                        return -EPERM;
+               if (bi.data.calibrate > INT_MAX / s->par.bitrate)
+                       return -EINVAL;
                s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
                return 0;