[patch] wan/x25_asy: integer overflow in x25_asy_change_mtu()
From: Dan Carpenter <hidden>
Date: 2014-07-17 08:03:29
Also in:
kernel-janitors
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
If "newmtu * 2 + 4" is too large then it can cause an integer overflow leading to memory corruption. 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 <redacted>
diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c
index 5895f19..f04c8c1 100644
--- a/drivers/net/wan/x25_asy.c
+++ b/drivers/net/wan/x25_asy.c@@ -122,8 +122,11 @@ 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 > INT_MAX / 2 - 4) + return -EINVAL; + len = 2 * newmtu; xbuff = kmalloc(len + 4, GFP_ATOMIC); rbuff = kmalloc(len + 4, GFP_ATOMIC);