This is a note to let you know that I've just added the patch titled xfrm: fix policy lookup for ipv6 gre packets to the 5.16-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xfrm-fix-policy-lookup-for-ipv6-gre-packets.patch and it can be found in the queue-5.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bcf141b2eb551b3477b24997ebc09c65f117a803 Mon Sep 17 00:00:00 2001 From: Ghalem Boudour <ghalem.boudour@xxxxxxxxx> Date: Fri, 19 Nov 2021 18:20:16 +0100 Subject: xfrm: fix policy lookup for ipv6 gre packets From: Ghalem Boudour <ghalem.boudour@xxxxxxxxx> commit bcf141b2eb551b3477b24997ebc09c65f117a803 upstream. On egress side, xfrm lookup is called from __gre6_xmit() with the fl6_gre_key field not initialized leading to policies selectors check failure. Consequently, gre packets are sent without encryption. On ingress side, INET6_PROTO_NOPOLICY was set, thus packets were not checked against xfrm policies. Like for egress side, fl6_gre_key should be correctly set, this is now done in decode_session6(). Fixes: c12b395a4664 ("gre: Support GRE over IPv6") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ghalem Boudour <ghalem.boudour@xxxxxxxxx> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/ip6_gre.c | 5 ++++- net/xfrm/xfrm_policy.c | 21 +++++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -755,6 +755,7 @@ static netdev_tx_t __gre6_xmit(struct sk fl6->daddr = key->u.ipv6.dst; fl6->flowlabel = key->label; fl6->flowi6_uid = sock_net_uid(dev_net(dev), NULL); + fl6->fl6_gre_key = tunnel_id_to_key32(key->tun_id); dsfield = key->tos; flags = key->tun_flags & @@ -990,6 +991,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit fl6.daddr = key->u.ipv6.dst; fl6.flowlabel = key->label; fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL); + fl6.fl6_gre_key = tunnel_id_to_key32(key->tun_id); dsfield = key->tos; if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT)) @@ -1098,6 +1100,7 @@ static void ip6gre_tnl_link_config_commo fl6->flowi6_oif = p->link; fl6->flowlabel = 0; fl6->flowi6_proto = IPPROTO_GRE; + fl6->fl6_gre_key = t->parms.o_key; if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS)) fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo; @@ -1544,7 +1547,7 @@ static void ip6gre_fb_tunnel_init(struct static struct inet6_protocol ip6gre_protocol __read_mostly = { .handler = gre_rcv, .err_handler = ip6gre_err, - .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL, + .flags = INET6_PROTO_FINAL, }; static void ip6gre_destroy_tunnels(struct net *net, struct list_head *head) --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -33,6 +33,7 @@ #include <net/flow.h> #include <net/xfrm.h> #include <net/ip.h> +#include <net/gre.h> #if IS_ENABLED(CONFIG_IPV6_MIP6) #include <net/mip6.h> #endif @@ -3422,6 +3423,26 @@ decode_session6(struct sk_buff *skb, str } fl6->flowi6_proto = nexthdr; return; + case IPPROTO_GRE: + if (!onlyproto && + (nh + offset + 12 < skb->data || + pskb_may_pull(skb, nh + offset + 12 - skb->data))) { + struct gre_base_hdr *gre_hdr; + __be32 *gre_key; + + nh = skb_network_header(skb); + gre_hdr = (struct gre_base_hdr *)(nh + offset); + gre_key = (__be32 *)(gre_hdr + 1); + + if (gre_hdr->flags & GRE_KEY) { + if (gre_hdr->flags & GRE_CSUM) + gre_key++; + fl6->fl6_gre_key = *gre_key; + } + } + fl6->flowi6_proto = nexthdr; + return; + #if IS_ENABLED(CONFIG_IPV6_MIP6) case IPPROTO_MH: offset += ipv6_optlen(exthdr); Patches currently in stable-queue which might be from ghalem.boudour@xxxxxxxxx are queue-5.16/xfrm-fix-policy-lookup-for-ipv6-gre-packets.patch