From: huaibin Wang <[email protected]>

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

===============

commit ac37e2515c1a89c477459a2020b6bfdedabdb91b upstream.

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 <[email protected]>
Signed-off-by: Nicolas Dichtel <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
 include/net/dst.h      |  1 +
 net/xfrm/xfrm_policy.c | 12 ++++++------
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/net/dst.h b/include/net/dst.h
index 9c123761efc1..30cd2f9cd1dd 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -469,6 +469,7 @@ extern void         dst_init(void);
 enum {
        XFRM_LOOKUP_ICMP = 1 << 0,
        XFRM_LOOKUP_QUEUE = 1 << 1,
+       XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
 };
 
 struct flowi;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6b07a5913383..57674ddc683d 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2154,11 +2154,9 @@ restart:
                 * 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;
                }
                if (fl->flowi_flags & FLOWI_FLAG_CAN_SLEEP) {
                        DECLARE_WAITQUEUE(wait, current);
@@ -2224,7 +2222,8 @@ 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);
 }
@@ -2238,7 +2237,8 @@ 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);
-- 
2.4.6

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