[patch 07/26] [NETLINK]: Fix processing of fib_lookup netlink messages

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Thomas Graf <tgraf@xxxxxxx>

The receive path for fib_lookup netlink messages is lacking sanity
checks for header and payload and is thus vulnerable to malformed
netlink messages causing illegal memory references.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/ipv4/fib_frontend.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- linux-2.6.14.3.orig/net/ipv4/fib_frontend.c
+++ linux-2.6.14.3/net/ipv4/fib_frontend.c
@@ -545,12 +545,16 @@ static void nl_fib_input(struct sock *sk
 	struct sk_buff *skb = NULL;
         struct nlmsghdr *nlh = NULL;
 	struct fib_result_nl *frn;
-	int err;
 	u32 pid;     
 	struct fib_table *tb;
 	
-	skb = skb_recv_datagram(sk, 0, 0, &err);
+	skb = skb_dequeue(&sk->sk_receive_queue);
 	nlh = (struct nlmsghdr *)skb->data;
+	if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
+	    nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
+		kfree_skb(skb);
+		return;
+	}
 	
 	frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
 	tb = fib_get_table(frn->tb_id_in);

--
-
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