Commit:     e1af9f270b69a3ad1dcbabb404dd1f40a96f43f5
Parent:     afeb14b49098ba7a51c96e083a4105a0301f94c4
Author:     Paul Moore <[EMAIL PROTECTED]>
AuthorDate: Fri Dec 21 14:59:08 2007 -0800
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Mon Jan 28 15:00:02 2008 -0800

    [XFRM]: Drop packets when replay counter would overflow
    According to RFC4303, section 3.3.3 we need to drop outgoing packets which
    cause the replay counter to overflow:
       3.3.3.  Sequence Number Generation
       The sender's counter is initialized to 0 when an SA is established.
       The sender increments the sequence number (or ESN) counter for this
       SA and inserts the low-order 32 bits of the value into the Sequence
       Number field.  Thus, the first packet sent using a given SA will
       contain a sequence number of 1.
       If anti-replay is enabled (the default), the sender checks to ensure
       that the counter has not cycled before inserting the new value in the
       Sequence Number field.  In other words, the sender MUST NOT send a
       packet on an SA if doing so would cause the sequence number to cycle.
       An attempt to transmit a packet that would result in sequence number
       overflow is an auditable event.  The audit log entry for this event
       SHOULD include the SPI value, current date/time, Source Address,
       Destination Address, and (in IPv6) the cleartext Flow ID.
    Signed-off-by: Paul Moore <[EMAIL PROTECTED]>
    Acked-by: James Morris <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
 net/xfrm/xfrm_output.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 0951444..d73003c 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -57,8 +57,11 @@ static int xfrm_output_one(struct sk_buff *skb, int err)
                if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
                        XFRM_SKB_CB(skb)->seq = ++x->replay.oseq;
-                       if (unlikely(x->replay.oseq == 0))
+                       if (unlikely(x->replay.oseq == 0)) {
+                               x->replay.oseq--;
                                xfrm_audit_state_replay_overflow(x, skb);
+                               goto error;
+                       }
                        if (xfrm_aevent_is_on())
                                xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
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