From bcf66bf54aabffc150acd1c99e0f4bc51935eada Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Tue, 20 Sep 2011 23:38:58 +0000
Subject: [PATCH] xfrm: Perform a replay check after return from async
 codepaths

When asyncronous crypto algorithms are used, there might be many
packets that passed the xfrm replay check, but the replay advance
function is not called yet for these packets. So the replay check
function would accept a replay of all of these packets. Also the
system might crash if there are more packets in async processing
than the size of the anti replay window, because the replay advance
function would try to update the replay window beyond the bounds.

This pach adds a second replay check after resuming from the async
processing to fix these issues.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/xfrm/xfrm_input.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index a026b0ef2443c..54a0dc2e2f8d4 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -212,6 +212,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 		/* only the first xfrm gets the encap type */
 		encap_type = 0;
 
+		if (async && x->repl->check(x, skb, seq)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
+			goto drop_unlock;
+		}
+
 		x->repl->advance(x, seq);
 
 		x->curlft.bytes += skb->len;
-- 
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