[PATCH 3.2 055/106] ipv6: xfrm: Handle errors reported by xfrm6_find_1stfragopt()

[Ben Hutchings]

3.2.93-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

commit 6e80ac5cc992ab6256c3dae87f7e57db15e1a58c upstream.

xfrm6_find_1stfragopt() may now return an error code and we must
not treat it as a length.

Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options")
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Acked-by: Craig Gallek <kraig@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
 net/ipv6/xfrm6_mode_ro.c        | 2 ++
 net/ipv6/xfrm6_mode_transport.c | 2 ++
 2 files changed, 4 insertions(+)

--- a/net/ipv6/xfrm6_mode_ro.c
+++ b/net/ipv6/xfrm6_mode_ro.c
@@ -48,6 +48,8 @@ static int xfrm6_ro_output(struct xfrm_s
 	iph = ipv6_hdr(skb);
 
 	hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
+	if (hdr_len < 0)
+		return hdr_len;
 	skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
 	skb_set_network_header(skb, -x->props.header_len);
 	skb->transport_header = skb->network_header + hdr_len;
--- a/net/ipv6/xfrm6_mode_transport.c
+++ b/net/ipv6/xfrm6_mode_transport.c
@@ -28,6 +28,8 @@ static int xfrm6_transport_output(struct
 	iph = ipv6_hdr(skb);
 
 	hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
+	if (hdr_len < 0)
+		return hdr_len;
 	skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
 	skb_set_network_header(skb, -x->props.header_len);
 	skb->transport_header = skb->network_header + hdr_len;