hdlcdrv: Fix divide by zero in hdlcdrv_ioctl

[ Upstream commit fb3ce90b7d7761b6f7f28f0ff5c456ef6b5229a1 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Firo Yang 2017-05-26 22:37:38 +08:00 committed by Greg Kroah-Hartman
parent 65bd5b002c
commit b32436defc

View file

@ -574,6 +574,8 @@ 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;