From: Mark Tomlinson mark.tomlinson@alliedtelesis.co.nz
[ Upstream commit 272502fcb7cda01ab07fc2fcff82d1d2f73d43cc ]
When receiving an IPv4 packet inside an IPv6 GRE packet, and the IP6_TNL_F_RCV_DSCP_COPY flag is set on the tunnel, the IPv4 header would get corrupted. This is due to the common ip6_tnl_rcv() function assuming that the inner header is always IPv6. This patch checks the tunnel protocol for IPv4 inner packets, but still defaults to IPv6.
Fixes: 308edfdf1563 ("gre6: Cleanup GREv6 receive path, call common GRE functions") Signed-off-by: Mark Tomlinson mark.tomlinson@alliedtelesis.co.nz Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_tunnel.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -886,7 +886,15 @@ int ip6_tnl_rcv(struct ip6_tnl *t, struc struct metadata_dst *tun_dst, bool log_ecn_err) { - return __ip6_tnl_rcv(t, skb, tpi, tun_dst, ip6ip6_dscp_ecn_decapsulate, + int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t, + const struct ipv6hdr *ipv6h, + struct sk_buff *skb); + + dscp_ecn_decapsulate = ip6ip6_dscp_ecn_decapsulate; + if (tpi->proto == htons(ETH_P_IP)) + dscp_ecn_decapsulate = ip4ip6_dscp_ecn_decapsulate; + + return __ip6_tnl_rcv(t, skb, tpi, tun_dst, dscp_ecn_decapsulate, log_ecn_err); } EXPORT_SYMBOL(ip6_tnl_rcv);