[PATCH 4.4 49/87] ip6_tunnel: disable dst caching if tunnel is dual-stack

[Greg Kroah-Hartman]

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

------------------

From: Eli Cooper <elicooper@xxxxxxx>


[ Upstream commit 23263ec86a5f44312d2899323872468752324107 ]

When an ip6_tunnel is in mode 'any', where the transport layer
protocol can be either 4 or 41, dst_cache must be disabled.

This is because xfrm policies might apply to only one of the two
protocols. Caching dst would cause xfrm policies for one protocol
incorrectly used for the other.

Signed-off-by: Eli Cooper <elicooper@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/ip6_tunnel.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1083,10 +1083,11 @@ static int ip6_tnl_xmit2(struct sk_buff
 			memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
 			neigh_release(neigh);
 		}
-	} else if (!(t->parms.flags &
-		     (IP6_TNL_F_USE_ORIG_TCLASS | IP6_TNL_F_USE_ORIG_FWMARK))) {
-		/* enable the cache only only if the routing decision does
-		 * not depend on the current inner header value
+	} else if (t->parms.proto != 0 && !(t->parms.flags &
+					    (IP6_TNL_F_USE_ORIG_TCLASS |
+					     IP6_TNL_F_USE_ORIG_FWMARK))) {
+		/* enable the cache only if neither the outer protocol nor the
+		 * routing decision depends on the current inner header value
 		 */
 		use_cache = true;
 	}