commit ad8e4b75c8a7bed475d72ce09bf5267188621961
author Martin Murray <murrayma@citi.umich.edu> Tue Jan 10 13:02:29 2006 -0800
committer David S. Miller <davem@davemloft.net> Tue Jan 10 13:02:29 2006 -0800
tree fe9edd967818a744f87c2d1aa51443bae613fbbf
parent babbdb1a18d37e57acae7e348ef122f2b905df0a

[AF_NETLINK]: Fix DoS in netlink_rcv_skb()

From: Martin Murray <murrayma@citi.umich.edu>

Sanity check nlmsg_len during netlink_rcv_skb.  An nlmsg_len == 0 can
cause infinite loop in kernel, effectively DoSing machine.  Noted by
Matin Murray.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/af_netlink.c

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index a67f1b4..bb50c8a 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1422,7 +1422,7 @@
 	while (skb->len >= nlmsg_total_size(0)) {
 		nlh = (struct nlmsghdr *) skb->data;
 
-		if (skb->len < nlh->nlmsg_len)
+		if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
 			return 0;
 
 		total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len);