From: Thomas Graf <tgraf@suug.ch>
Date: Thu, 1 Dec 2005 22:05:12 +0000 (+0100)
Subject: [PATCH] NETLINK: Fix processing of fib_lookup netlink messages
X-Git-Tag: v2.6.14.4~18
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=450a53336ea85de85f5ab5b9d39bafbc67ee1ed8;p=thirdparty%2Fkernel%2Fstable.git

[PATCH] NETLINK: Fix processing of fib_lookup netlink messages

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@suug.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index e61bc7177eb1b..bc6f0a3698820 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -545,12 +545,16 @@ static void nl_fib_input(struct sock *sk, int len)
 	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);