xfrm: release dst_orig in case of error in xfrm_lookup()

dst_orig should be released on error. Function like __xfrm_route_forward()
expects that behavior.
Since a recent commit, xfrm_lookup() may also be called by xfrm_lookup_route(),
which expects the opposite.
Let's introduce a new flag (XFRM_LOOKUP_KEEP_DST_REF) to tell what should be
done in case of error.

Fixes: f92ee61982d("xfrm: Generate blackhole routes only from route lookup functions")
Signed-off-by: huaibin Wang <huaibin.wang@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index cee479bc655c..638af0655aaf 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2269,11 +2269,9 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
                  * have the xfrm_state's. We need to wait for KM to
                  * negotiate new SA's or bail out with error.*/
                 if (net->xfrm.sysctl_larval_drop) {
-                        dst_release(dst);
-                        xfrm_pols_put(pols, drop_pols);
                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES);
-
-                        return ERR_PTR(-EREMOTE);
+                        err = -EREMOTE;
+                        goto error;
                 }
 
                 err = -EAGAIN;
@@ -2324,7 +2322,8 @@ nopol:
 error:
         dst_release(dst);
 dropdst:
-        dst_release(dst_orig);
+        if (!(flags & XFRM_LOOKUP_KEEP_DST_REF))
+                dst_release(dst_orig);
         xfrm_pols_put(pols, drop_pols);
         return ERR_PTR(err);
 }
@@ -2338,7 +2337,8 @@ struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
                                     struct sock *sk, int flags)
 {
         struct dst_entry *dst = xfrm_lookup(net, dst_orig, fl, sk,
-                                            flags | XFRM_LOOKUP_QUEUE);
+                                            flags | XFRM_LOOKUP_QUEUE |
+                                            XFRM_LOOKUP_KEEP_DST_REF);
 
         if (IS_ERR(dst) && PTR_ERR(dst) == -EREMOTE)
                 return make_blackhole(net, dst_orig->ops->family, dst_orig);