Patchwork [3/3] ipv4: Fix packet size calculation for raw IPsec packets in __ip_append_data

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Submitter Steffen Klassert
Date June 6, 2011, 6:48 a.m.
Message ID <20110606064847.GD31505@secunet.com>
Download mbox | patch
Permalink /patch/98808/
State Accepted
Delegated to: David Miller
Headers show

Comments

Steffen Klassert - June 6, 2011, 6:48 a.m.
We assume that transhdrlen is positive on the first fragment
which is wrong for raw packets. So we don't add exthdrlen to the
packet size for raw packets. This leads to a reallocation on IPsec
because we have not enough headroom on the skb to place the IPsec
headers. This patch fixes this by adding exthdrlen to the packet
size whenever the send queue of the socket is empty. This issue was
introduced with git commit 1470ddf7 (inet: Remove explicit write
references to sk/inet in ip_append_data)

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/ip_output.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
David Miller - June 9, 2011, 9:50 p.m.
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Mon, 6 Jun 2011 08:48:47 +0200

> We assume that transhdrlen is positive on the first fragment
> which is wrong for raw packets. So we don't add exthdrlen to the
> packet size for raw packets. This leads to a reallocation on IPsec
> because we have not enough headroom on the skb to place the IPsec
> headers. This patch fixes this by adding exthdrlen to the packet
> size whenever the send queue of the socket is empty. This issue was
> introduced with git commit 1470ddf7 (inet: Remove explicit write
> references to sk/inet in ip_append_data)
> 
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Applied, thanks.
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Patch

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index a16859b..6b894d4 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -799,7 +799,9 @@  static int __ip_append_data(struct sock *sk,
 	int csummode = CHECKSUM_NONE;
 	struct rtable *rt = (struct rtable *)cork->dst;
 
-	exthdrlen = transhdrlen ? rt->dst.header_len : 0;
+	skb = skb_peek_tail(queue);
+
+	exthdrlen = !skb ? rt->dst.header_len : 0;
 	length += exthdrlen;
 	transhdrlen += exthdrlen;
 	mtu = cork->fragsize;
@@ -825,8 +827,6 @@  static int __ip_append_data(struct sock *sk,
 	    !exthdrlen)
 		csummode = CHECKSUM_PARTIAL;
 
-	skb = skb_peek_tail(queue);
-
 	cork->length += length;
 	if (((length > mtu) || (skb && skb_is_gso(skb))) &&
 	    (sk->sk_protocol == IPPROTO_UDP) &&