[NET]: Clone the sk_buff 'iif' field in __skb_clone()

Both NetLabel and SELinux (other LSMs may grow to use it as well) rely
on the 'iif' field to determine the receiving network interface of
inbound packets.  Unfortunately, at present this field is not
preserved across a skb clone operation which can lead to garbage
values if the cloned skb is sent back through the network stack.  This
patch corrects this problem by properly copying the 'iif' field in
__skb_clone() and removing the 'iif' field assignment from
skb_act_clone() since it is no longer needed.

Also, while we are here, put the assignments in the same order as the
offsets to reduce cacheline bounces.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index c9265518a378ac6ca93ab1a74745d8149d8fcf2b..4c3b35153c3722b2a5871cf78ed11023f7fa9e17 100644 (file)
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -325,7 +325,6 @@ static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask)
                n->tc_verd = SET_TC_VERD(n->tc_verd, 0);
                n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
                n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
-               n->iif = skb->iif;
        }
        return n;
 }

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 5b4ce9b4dd2060c9fd5920bfad967493b7e7eea6..b6283779e93d4432f9f9cad9f4c7a1610b3d1763 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -416,16 +416,17 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
        C(len);
        C(data_len);
        C(mac_len);
-       n->cloned = 1;
        n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
+       n->cloned = 1;
        n->nohdr = 0;
        n->destructor = NULL;
-       C(truesize);
-       atomic_set(&n->users, 1);
-       C(head);
-       C(data);
+       C(iif);
        C(tail);
        C(end);
+       C(head);
+       C(data);
+       C(truesize);
+       atomic_set(&n->users, 1);
 
        atomic_inc(&(skb_shinfo(skb)->dataref));
        skb->cloned = 1;