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Message-Id: <20071221.145916.103462184.davem@davemloft.net>
Date: Fri, 21 Dec 2007 14:59:16 -0800 (PST)
From: David Miller <davem@...emloft.net>
To: paul.moore@...com
Cc: netdev@...r.kernel.org, linux-audit@...hat.com,
latten@...tin.ibm.com
Subject: Re: [PATCH 2/2] XFRM: Drop packets when replay counter would
overflow
From: Paul Moore <paul.moore@...com>
Date: Fri, 21 Dec 2007 09:15:00 -0500
> 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 <paul.moore@...com>
Applied.
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