Patch "hdlcdrv: Fix divide by zero in hdlcdrv_ioctl" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

hdlcdrv: Fix divide by zero in hdlcdrv_ioctl

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hdlcdrv-fix-divide-by-zero-in-hdlcdrv_ioctl.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Firo Yang <[email protected]>
Date: Fri, 26 May 2017 22:37:38 +0800
Subject: hdlcdrv: Fix divide by zero in hdlcdrv_ioctl

From: Firo Yang <[email protected]>

[ 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.

---
 drivers/net/hamradio/hdlcdrv.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -576,6 +576,8 @@ static int hdlcdrv_ioctl(struct net_devi
 	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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/hdlcdrv-fix-divide-by-zero-in-hdlcdrv_ioctl.patch