[kernel] r22475 - in dists/sid/linux/debian: . patches patches/bugfix/all

[Ben Hutchings]

Author: benh
Date: Mon Apr  6 17:45:04 2015
New Revision: 22475

Log:
ipv6: Don't reduce hop limit for an interface (CVE-2015-2922)

Added:
   dists/sid/linux/debian/patches/bugfix/all/ipv6-don-t-reduce-hop-limit-for-an-interface.patch
Modified:
   dists/sid/linux/debian/changelog
   dists/sid/linux/debian/patches/series

Modified: dists/sid/linux/debian/changelog
==============================================================================
--- dists/sid/linux/debian/changelog	Mon Apr  6 17:31:57 2015	(r22474)
+++ dists/sid/linux/debian/changelog	Mon Apr  6 17:45:04 2015	(r22475)
@@ -186,6 +186,7 @@
   * ext4: allocate entire range in zero range (CVE-2015-0275)
   * [x86] microcode/intel: Guard against stack overflow in the loader
     (CVE-2015-2666)
+  * ipv6: Don't reduce hop limit for an interface (CVE-2015-2922)
 
  -- Ian Campbell <ijc at debian.org>  Wed, 18 Mar 2015 21:07:15 +0000
 

Added: dists/sid/linux/debian/patches/bugfix/all/ipv6-don-t-reduce-hop-limit-for-an-interface.patch
==============================================================================
--- /dev/null	00:00:00 1970	(empty, because file is newly added)
+++ dists/sid/linux/debian/patches/bugfix/all/ipv6-don-t-reduce-hop-limit-for-an-interface.patch	Mon Apr  6 17:45:04 2015	(r22475)
@@ -0,0 +1,43 @@
+From: "D.S. Ljungmark" <ljungmark at modio.se>
+Date: Wed, 25 Mar 2015 09:28:15 +0100
+Subject: ipv6: Don't reduce hop limit for an interface
+Origin: https://git.kernel.org/linus/6fd99094de2b83d1d4c8457f2c83483b2828e75a
+
+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>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ net/ipv6/ndisc.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+--- a/net/ipv6/ndisc.c
++++ b/net/ipv6/ndisc.c
+@@ -1190,7 +1190,14 @@ static void ndisc_router_discovery(struc
+ 	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);

Modified: dists/sid/linux/debian/patches/series
==============================================================================
--- dists/sid/linux/debian/patches/series	Mon Apr  6 17:31:57 2015	(r22474)
+++ dists/sid/linux/debian/patches/series	Mon Apr  6 17:45:04 2015	(r22475)
@@ -561,3 +561,4 @@
 bugfix/all/ext4-fix-accidental-flag-aliasing-in-ext4_map_blocks.patch
 bugfix/all/ext4-allocate-entire-range-in-zero-range.patch
 bugfix/x86/x86-microcode-intel-guard-against-stack-overflow-in-.patch
+bugfix/all/ipv6-don-t-reduce-hop-limit-for-an-interface.patch