[PATCH net] net: xfrm: don't double-hold dst when sk_policy in use.

While removing dst_entry garbage collection, commit 52df157f17e5
("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
changed xfrm_resolve_and_create_bundle so it returns an xdst with
a refcount of 1 instead of 0.

However, it did not delete the dst_hold performed by xfrm_lookup
when a per-socket policy is in use. This means that when a
socket policy is in use, dst entries returned by xfrm_lookup have
a refcount of 2, and are not freed when no longer in use.

Cc: Wei Wang <redacted>
Fixes: 52df157f17 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
Tested: https://android-review.googlesource.com/417481
Tested: https://android-review.googlesource.com/418659
Tested: https://android-review.googlesource.com/424463
Tested: https://android-review.googlesource.com/452776 passes on net-next
Signed-off-by: Lorenzo Colitti <redacted>
---
 net/xfrm/xfrm_policy.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6f5a0dad50..69b16ee327 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c

@@ -2226,7 +2226,6 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
 				goto no_transform;
 			}
 
-			dst_hold(&xdst->u.dst);
 			route = xdst->route;
 		}
 	}

-- 
2.14.1.480.gb18f417b89-goog

While removing dst_entry garbage collection, commit 52df157f17e5
("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
changed xfrm_resolve_and_create_bundle so it returns an xdst with
a refcount of 1 instead of 0.

However, it did not delete the dst_hold performed by xfrm_lookup
when a per-socket policy is in use. This means that when a
socket policy is in use, dst entries returned by xfrm_lookup have
a refcount of 2, and are not freed when no longer in use.

Cc: Wei Wang <redacted>
Fixes: 52df157f17 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
Tested: https://android-review.googlesource.com/417481
Tested: https://android-review.googlesource.com/418659
Tested: https://android-review.googlesource.com/424463
Tested: https://android-review.googlesource.com/452776 passes on net-next
Signed-off-by: Lorenzo Colitti <redacted>

Thanks for the fix.

Acked-by: Wei Wang <redacted>


On Wed, Aug 23, 2017 at 1:14 AM, Lorenzo Colitti [off-list ref] wrote:

On Wed, Aug 23, 2017 at 05:14:39PM +0900, Lorenzo Colitti wrote:

While removing dst_entry garbage collection, commit 52df157f17e5
("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
changed xfrm_resolve_and_create_bundle so it returns an xdst with
a refcount of 1 instead of 0.

However, it did not delete the dst_hold performed by xfrm_lookup
when a per-socket policy is in use. This means that when a
socket policy is in use, dst entries returned by xfrm_lookup have
a refcount of 2, and are not freed when no longer in use.

Cc: Wei Wang <redacted>
Fixes: 52df157f17 ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle")
Tested: https://android-review.googlesource.com/417481
Tested: https://android-review.googlesource.com/418659
Tested: https://android-review.googlesource.com/424463
Tested: https://android-review.googlesource.com/452776 passes on net-next
Signed-off-by: Lorenzo Colitti <redacted>

Patch applied, thanks a lot!