netdev - xfrm: Always zero high-order sequence number bits

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Message-ID: <20150520163810.GA13992@gondor.apana.org.au>
Date:	Thu, 21 May 2015 00:38:12 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Steffen Klassert <steffen.klassert@...unet.com>,
	netdev@...r.kernel.org
Subject: xfrm: Always zero high-order sequence number bits

As we're now always including the high bits of the sequence number
in the IV generation process we need to ensure that they don't
contain crap.

This patch ensures that the high sequence bits are always zeroed
so that we don't leak random data into the IV.

Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

diff --git a/net/xfrm/xfrm_replay.c b/net/xfrm/xfrm_replay.c
index dab57da..4fd725a 100644
--- a/net/xfrm/xfrm_replay.c
+++ b/net/xfrm/xfrm_replay.c
@@ -99,6 +99,7 @@ static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
 
 	if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 		XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
+		XFRM_SKB_CB(skb)->seq.output.hi = 0;
 		if (unlikely(x->replay.oseq == 0)) {
 			x->replay.oseq--;
 			xfrm_audit_state_replay_overflow(x, skb);
@@ -177,6 +178,7 @@ static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
 
 	if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 		XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
+		XFRM_SKB_CB(skb)->seq.output.hi = 0;
 		if (unlikely(replay_esn->oseq == 0)) {
 			replay_esn->oseq--;
 			xfrm_audit_state_replay_overflow(x, skb);

-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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