Commit a28d0e87 authored Jul 17, 2014 by Dan Carpenter Committed by David S. Miller Jul 17, 2014

wan/x25_asy: integer overflow in x25_asy_change_mtu()



If "newmtu * 2 + 4" is too large then it can cause an integer overflow
leading to memory corruption.  Eric Dumazet suggests that 65534 is a
reasonable upper limit.

Btw, "newmtu" is not allowed to be a negative number because of the
check in dev_set_mtu(), so that's ok.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent cc25eaae

drivers/net/wan/x25_asy.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -122,8 +122,12 @@ static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
		{
		struct x25_asy *sl = netdev_priv(dev);
		unsigned char xbuff, rbuff;
		int len = 2 * newmtu;
		int len;

		if (newmtu > 65534)
		return -EINVAL;

		len = 2 * newmtu;
		xbuff = kmalloc(len + 4, GFP_ATOMIC);
		rbuff = kmalloc(len + 4, GFP_ATOMIC);