netdev - [PATCH net v2 1/2] xfrm6: Fix IPv6 payload_len in xfrm6_transport

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Message-Id: <1498120631-4291-1-git-send-email-yossiku@mellanox.com>
Date:   Thu, 22 Jun 2017 11:37:10 +0300
From:   yossiku@...lanox.com
To:     netdev@...r.kernel.org, Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>
Cc:     Yevgeny Kliteynik <kliteyn@...lanox.com>,
        Boris Pismenny <borisp@...lanox.com>,
        Ilan Tayari <ilant@...lanox.com>,
        Yossi Kuperman <yossiku@...lanox.com>
Subject: [PATCH net v2 1/2] xfrm6: Fix IPv6 payload_len in xfrm6_transport_finish

From: Yossi Kuperman <yossiku@...lanox.com>

IPv6 payload length indicates the size of the payload, including any
extension headers.

In xfrm6_transport_finish, ipv6_hdr(skb)->payload_len is set to the
payload size only, regardless of the presence of any extension headers.
After ESP GRO transport mode decapsulation, ipv6_rcv trims the packet
according to the wrong payload_len, thus corrupting the packet.

Set payload_len to account for extension headers as well.

Fixes: 7785bba299a8 ("esp: Add a software GRO codepath")
Signed-off-by: Yossi Kuperman <yossiku@...lanox.com>
---
v1 -> v2:
	- Fix the "Fixes" tag
---
 net/ipv6/xfrm6_input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c
index 08a807b..3ef5d91 100644
--- a/net/ipv6/xfrm6_input.c
+++ b/net/ipv6/xfrm6_input.c
@@ -43,8 +43,8 @@ int xfrm6_transport_finish(struct sk_buff *skb, int async)
 		return 1;
 #endif
 
-	ipv6_hdr(skb)->payload_len = htons(skb->len);
 	__skb_push(skb, skb->data - skb_network_header(skb));
+	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 
 	if (xo && (xo->flags & XFRM_GRO)) {
 		skb_mac_header_rebuild(skb);
-- 
2.8.1