[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>
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);