From mboxrd@z Thu Jan 1 00:00:00 1970 From: Firo Yang Subject: [[PATCH v1]] hdlcdrv: fix divide error bug if bitrate is 0 Date: Thu, 18 May 2017 12:02:18 +0800 Message-ID: <1495080138-21695-1-git-send-email-firogm@gmail.com> Cc: linux-hams@vger.kernel.org, netdev@vger.kernel.org, dvyukov@google.com, syzkaller@googlegroups.com, davem@davemloft.net, gregkh@linuxfoundation.org, Firo Yang To: t.sailer@alumni.ethz.ch, wharms@bfs.de Return-path: Sender: linux-hams-owner@vger.kernel.org List-Id: netdev.vger.kernel.org The divisor s->par.bitrate will always be 0 until initialized by ndo_open() and hdlcdrv_open(). In order to fix this divide zero error, check whether the netdevice was opened by ndo_open() before performing divide.And we also check the the value of bitrate in case of bad setting of it. Reported-by: Dmitry Vyukov Signed-off-by: Firo Yang --- v0->v1: Reviewed by walter harms . Return ENODEV instead of EPERM if !netif_running(dev) Check if s->par.bitrate > 0. drivers/net/hamradio/hdlcdrv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c index 8c3633c..b0f417f 100644 --- a/drivers/net/hamradio/hdlcdrv.c +++ b/drivers/net/hamradio/hdlcdrv.c @@ -576,6 +576,10 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) case HDLCDRVCTL_CALIBRATE: if(!capable(CAP_SYS_RAWIO)) return -EPERM; + if (!netif_running(dev)) + return -ENODEV; + 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