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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>
This commit is contained in:
Dan Carpenter 2014-07-17 13:50:45 +03:00 committed by David S. Miller
parent cc25eaae23
commit a28d0e873d
1 changed files with 5 additions and 1 deletions
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6
drivers/net/wan/x25_asy.c
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@ -122,8 +122,12 @@ static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
{ {
struct x25_asy *sl = netdev_priv(dev); struct x25_asy *sl = netdev_priv(dev);
unsigned char *xbuff, *rbuff; unsigned char *xbuff, *rbuff;
int len = 2 * newmtu; int len;
if (newmtu > 65534)
return -EINVAL;
len = 2 * newmtu;
xbuff = kmalloc(len + 4, GFP_ATOMIC); xbuff = kmalloc(len + 4, GFP_ATOMIC);
rbuff = kmalloc(len + 4, GFP_ATOMIC); rbuff = kmalloc(len + 4, GFP_ATOMIC);