From: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz> stable inclusion from linux-4.19.143 commit c3f242a608040074ff54fc67d74b168408c92899 -------------------------------- [ 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> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Aichun Li <liaichun@huawei.com> Reviewed-by: wangxiaopeng <wangxiaopeng7@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/ipv6/ip6_tunnel.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 8e70a015c792..b825ac025d5b 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -865,7 +865,15 @@ int ip6_tnl_rcv(struct ip6_tnl *t, struct sk_buff *skb, 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); -- 2.25.1