[patch 8/9] xfrm: fix fragmentation for ipv4 xfrm tunnel

From: Greg KH
Date: Fri Jul 25 2008 - 19:13:34 EST


2.6.25-stable review patch. If anyone has any objections, please let us
know.

------------------
From: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>

[ Upstream commit fe833fca2eac6b3d3ad5e35f44ad4638362f1da8 ]

When generating the ip header for the transformed packet we just copy
the frag_off field of the ip header from the original packet to the ip
header of the new generated packet. If we receive a packet as a chain
of fragments, all but the last of the new generated packets have the
IP_MF flag set. We have to mask the frag_off field to only keep the
IP_DF flag from the original packet. This got lost with git commit
36cf9acf93e8561d9faec24849e57688a81eb9c5 ("[IPSEC]: Separate
inner/outer mode processing on output")

Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
net/ipv4/xfrm4_mode_tunnel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -52,7 +52,7 @@ static int xfrm4_mode_tunnel_output(stru
IP_ECN_clear(top_iph);

top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
- 0 : XFRM_MODE_SKB_CB(skb)->frag_off;
+ 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
ip_select_ident(top_iph, dst->child, NULL);

top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);

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