From b32436defcd0a531677700b93a3174619eb3f1e8 Mon Sep 17 00:00:00 2001 From: Firo Yang Date: Fri, 26 May 2017 22:37:38 +0800 Subject: [PATCH] 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 Signed-off-by: Firo Yang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/hamradio/hdlcdrv.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c index 49fe59b..a75ce90 100644 --- a/drivers/net/hamradio/hdlcdrv.c +++ b/drivers/net/hamradio/hdlcdrv.c @@ -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; -- 2.7.4