netdev - [PATCH] hdlcdrv: fix divide error bug if bitrate is 0

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Message-Id: <20170517123549.22659-1-firogm@gmail.com>
Date:   Wed, 17 May 2017 20:35:49 +0800
From:   Firo Yang <firogm@...il.com>
To:     t.sailer@...mni.ethz.ch
Cc:     davem@...emloft.net, gregkh@...uxfoundation.org,
        linux-hams@...r.kernel.org, netdev@...r.kernel.org,
        dvyukov@...gle.com, syzkaller@...glegroups.com,
        Firo Yang <firogm@...il.com>
Subject: [PATCH] hdlcdrv: fix divide error bug if bitrate is 0

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.

Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
Signed-off-by: Firo Yang <firogm@...il.com>
---
 drivers/net/hamradio/hdlcdrv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c
index 8c3633c..3c783fd 100644
--- a/drivers/net/hamradio/hdlcdrv.c
+++ b/drivers/net/hamradio/hdlcdrv.c
@@ -574,7 +574,7 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 		break;		
 
 	case HDLCDRVCTL_CALIBRATE:
-		if(!capable(CAP_SYS_RAWIO))
+		if (!capable(CAP_SYS_RAWIO) || !netif_running(dev))
 			return -EPERM;
 		if (bi.data.calibrate > INT_MAX / s->par.bitrate)
 			return -EINVAL;
-- 
2.9.4