xfrm: Refcount destination entry on xfrm_lookup

BugLink: http://bugs.launchpad.net/bugs/769042

[ Upstream commit fbd5060875d25f7764fd1c3d35b83a8ed1d88d7b ]

We return a destination entry without refcount if a socket
policy is found in xfrm_lookup. This triggers a warning on
a negative refcount when freeeing this dst entry. So take
a refcount in this case to fix it.

This refcount was forgotten when xfrm changed to cache bundles
instead of policies for outgoing flows.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6459588..8da2741 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1778,6 +1778,8 @@ restart:
                                goto no_transform;
                        }
 
+                       dst_hold(&xdst->u.dst);
+
                        spin_lock_bh(&xfrm_policy_sk_bundle_lock);
                        xdst->u.dst.next = xfrm_policy_sk_bundles;
                        xfrm_policy_sk_bundles = &xdst->u.dst;