xfrm: fix bug with DSCP copy to v6 from v4 tunnel

[ Upstream commit 420e714e2c80b9fa7750253bcccc3c65672b28d9 ]

When copying the DSCP bits for decap-dscp into IPv6 don't assume the
outer encap is always IPv6. Instead, as with the inner IPv4 case, copy
the DSCP bits from the correctly saved "tos" value in the control block.

Fixes: 9aba4012a815 ("[IPSEC]: Separate inner/outer mode processing on input")
Signed-off-by: Christian Hopps <chopps@chopps.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 97074f6f2bdee947b7691be123389d68eca9d828..2defd89da700dd8c0ae40d742a406388bd931f76 100644 (file)
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -279,8 +279,7 @@ static int xfrm6_remove_tunnel_encap(struct xfrm_state *x, struct sk_buff *skb)
                goto out;
 
        if (x->props.flags & XFRM_STATE_DECAP_DSCP)
-               ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
-                              ipipv6_hdr(skb));
+               ipv6_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipipv6_hdr(skb));
        if (!(x->props.flags & XFRM_STATE_NOECN))
                ipip6_ecn_decapsulate(skb);