jwboyer pushed to kernel (f20). "DoS against IPv6 stacks due to improper handling of RA (rhbz 1203712 1208491)"

[notifications at fedoraproject.org]

>From c293048f8ee70ca5ca2ccb3203a4b76cd41b7306 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer at fedoraproject.org>
Date: Thu, 2 Apr 2015 08:23:52 -0400
Subject: DoS against IPv6 stacks due to improper handling of RA (rhbz 1203712
 1208491)


diff --git a/ipv6-Don-t-reduce-hop-limit-for-an-interface.patch b/ipv6-Don-t-reduce-hop-limit-for-an-interface.patch
new file mode 100644
index 0000000..60f2490
--- /dev/null
+++ b/ipv6-Don-t-reduce-hop-limit-for-an-interface.patch
@@ -0,0 +1,46 @@
+From: "D.S. Ljungmark" <ljungmark at modio.se>
+Date: Wed, 25 Mar 2015 09:28:15 +0100
+Subject: [PATCH] ipv6: Don't reduce hop limit for an interface
+
+A local route may have a lower hop_limit set than global routes do.
+
+RFC 3756, Section 4.2.7, "Parameter Spoofing"
+
+>   1.  The attacker includes a Current Hop Limit of one or another small
+>       number which the attacker knows will cause legitimate packets to
+>       be dropped before they reach their destination.
+
+>   As an example, one possible approach to mitigate this threat is to
+>   ignore very small hop limits.  The nodes could implement a
+>   configurable minimum hop limit, and ignore attempts to set it below
+>   said limit.
+
+Signed-off-by: D.S. Ljungmark <ljungmark at modio.se>
+Acked-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
+---
+ net/ipv6/ndisc.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
+index 682866777d53..d375ce60463e 100644
+--- a/net/ipv6/ndisc.c
++++ b/net/ipv6/ndisc.c
+@@ -1216,7 +1216,14 @@ static void ndisc_router_discovery(struct sk_buff *skb)
+ 	if (rt)
+ 		rt6_set_expires(rt, jiffies + (HZ * lifetime));
+ 	if (ra_msg->icmph.icmp6_hop_limit) {
+-		in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
++		/* Only set hop_limit on the interface if it is higher than
++		 * the current hop_limit.
++		 */
++		if (in6_dev->cnf.hop_limit < ra_msg->icmph.icmp6_hop_limit) {
++			in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
++		} else {
++			ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than current\n");
++		}
+ 		if (rt)
+ 			dst_metric_set(&rt->dst, RTAX_HOPLIMIT,
+ 				       ra_msg->icmph.icmp6_hop_limit);
+-- 
+2.1.0
+
diff --git a/kernel.spec b/kernel.spec
index e9a0759..417005d 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -781,6 +781,9 @@ Patch26176: sunrpc-make-debugfs-file-creation-failure-non-fatal.patch
 #rhbz 1207789
 Patch26177: tg3-Hold-tp-lock-before-calling-tg3_halt-from-tg3_in.patch
 
+#CVE-2015-XXXX rhbz 1203712 1208491
+Patch26178: ipv6-Don-t-reduce-hop-limit-for-an-interface.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -1531,6 +1534,9 @@ ApplyPatch sunrpc-make-debugfs-file-creation-failure-non-fatal.patch
 #rhbz 1207789
 ApplyPatch tg3-Hold-tp-lock-before-calling-tg3_halt-from-tg3_in.patch
 
+#CVE-2015-XXXX rhbz 1203712 1208491
+ApplyPatch ipv6-Don-t-reduce-hop-limit-for-an-interface.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -2342,6 +2348,9 @@ fi
 #                 ||----w |
 #                 ||     ||
 %changelog
+* Thu Apr 02 2015 Josh Boyer <jwboyer at fedoraproject.org>
+- DoS against IPv6 stacks due to improper handling of RA (rhbz 1203712 1208491)
+
 * Wed Apr 01 2015 Josh Boyer <jwboyer at fedoraproject.org>
 - Backport patch to fix tg3 deadlock (rhbz 1207789)
 - Fix gssproxy (rhbz 1203913)
-- 
cgit v0.10.2


	http://pkgs.fedoraproject.org/cgit/kernel.git/commit/?h=f20&id=c293048f8ee70ca5ca2ccb3203a4b76cd41b7306