[PATCH 06/08] TCP: Do not use inet->id of global tcp_socket when sending RST (CVE-2006-1242)

[Greg KH <gregkh@suse.de>]

From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>


The problem is in ip_push_pending_frames(), which uses:

        if (!df) {
                __ip_select_ident(iph, &rt->u.dst, 0);
        } else {
                iph->id = htons(inet->id++);
        }

instead of ip_select_ident().

Right now I think the code is a nonsense. Most likely, I copied it from
old ip_build_xmit(), where it was really special, we had to decide
whether to generate unique ID when generating the first (well, the last)
fragment.

In ip_push_pending_frames() it does not make sense, it should use plain
ip_select_ident() instead.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

 net/ipv4/ip_output.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- linux-2.6.15.6.orig/net/ipv4/ip_output.c
+++ linux-2.6.15.6/net/ipv4/ip_output.c
@@ -1237,11 +1237,7 @@ int ip_push_pending_frames(struct sock *
 	iph->tos = inet->tos;
 	iph->tot_len = htons(skb->len);
 	iph->frag_off = df;
-	if (!df) {
-		__ip_select_ident(iph, &rt->u.dst, 0);
-	} else {
-		iph->id = htons(inet->id++);
-	}
+	ip_select_ident(iph, &rt->u.dst, sk);
 	iph->ttl = ttl;
 	iph->protocol = sk->sk_protocol;
 	iph->saddr = rt->rt_src;