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

[ Upstream commit e9db5c21d3646a6454fcd04938dd215ac3ab620a ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c
index 3169252613fa..5d78c1d08abd 100644
--- 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;