xfrm: replay: Fix the update of replay_esn->oseq_hi for GSO

When skb needs GSO and wrap around happens, if xo->seq.low (seqno of
the first skb segment) is before the last seq number but oseq (seqno
of the last segment) is after it, xo->seq.low is still bigger than
replay_esn->oseq while oseq is smaller than it, so the update of
replay_esn->oseq_hi is missed for this case wrap around because of
the change in the cited commit.

For example, if sending a packet with gso_segs=3 while old
replay_esn->oseq=0xfffffffe, we calculate:
    xo->seq.low = 0xfffffffe + 1 = 0x0xffffffff
    oseq = 0xfffffffe + 3 = 0x1
(oseq < replay_esn->oseq) is true, but (xo->seq.low <
replay_esn->oseq) is false, so replay_esn->oseq_hi is not incremented.

To fix this issue, change the outer checking back for the update of
replay_esn->oseq_hi. And add new checking inside for the update of
packet's oseq_hi.

Fixes: 4b549ccce941 ("xfrm: replay: Fix ESN wrap around for GSO")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index bc56c6305725275ea2286373543af5d9333e34f4..235bbefc2abae29363c7e5b395cc65821f2b3feb 100644 (file)
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -714,10 +714,12 @@ static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff
                        oseq += skb_shinfo(skb)->gso_segs;
                }
 
-               if (unlikely(xo->seq.low < replay_esn->oseq)) {
-                       XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
-                       xo->seq.hi = oseq_hi;
-                       replay_esn->oseq_hi = oseq_hi;
+               if (unlikely(oseq < replay_esn->oseq)) {
+                       replay_esn->oseq_hi = ++oseq_hi;
+                       if (xo->seq.low < replay_esn->oseq) {
+                               XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
+                               xo->seq.hi = oseq_hi;
+                       }
                        if (replay_esn->oseq_hi == 0) {
                                replay_esn->oseq--;
                                replay_esn->oseq_hi--;