[PATCH 4.4 37/74] netfilter: use fwmark_reflect in nf_send_reset

From: Greg Kroah-Hartman
Date: Mon Jan 29 2018 - 15:38:43 EST


4.4-stable review patch. If anyone has any objections, please let me know.

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

From: Pau Espin Pedrol <pau.espin@xxxxxxxxxxxx>

commit cc31d43b4154ad5a7d8aa5543255a93b7e89edc2 upstream.

Otherwise, RST packets generated by ipt_REJECT always have mark 0 when
the routing is checked later in the same code path.

Fixes: e110861f8609 ("net: add a sysctl to reflect the fwmark on replies")
Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
Signed-off-by: Pau Espin Pedrol <pau.espin@xxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Acked-by: Michal Kubecek <mkubecek@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
net/ipv4/netfilter/nf_reject_ipv4.c | 2 ++
net/ipv6/netfilter/nf_reject_ipv6.c | 3 +++
2 files changed, 5 insertions(+)

--- a/net/ipv4/netfilter/nf_reject_ipv4.c
+++ b/net/ipv4/netfilter/nf_reject_ipv4.c
@@ -124,6 +124,8 @@ void nf_send_reset(struct net *net, stru
/* ip_route_me_harder expects skb->dst to be set */
skb_dst_set_noref(nskb, skb_dst(oldskb));

+ nskb->mark = IP4_REPLY_MARK(net, oldskb->mark);
+
skb_reserve(nskb, LL_MAX_HEADER);
niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
ip4_dst_hoplimit(skb_dst(nskb)));
--- a/net/ipv6/netfilter/nf_reject_ipv6.c
+++ b/net/ipv6/netfilter/nf_reject_ipv6.c
@@ -157,6 +157,7 @@ void nf_send_reset6(struct net *net, str
fl6.daddr = oip6h->saddr;
fl6.fl6_sport = otcph->dest;
fl6.fl6_dport = otcph->source;
+ fl6.flowi6_mark = IP6_REPLY_MARK(net, oldskb->mark);
security_skb_classify_flow(oldskb, flowi6_to_flowi(&fl6));
dst = ip6_route_output(net, NULL, &fl6);
if (dst == NULL || dst->error) {
@@ -180,6 +181,8 @@ void nf_send_reset6(struct net *net, str

skb_dst_set(nskb, dst);

+ nskb->mark = fl6.flowi6_mark;
+
skb_reserve(nskb, hh_len + dst->header_len);
ip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
ip6_dst_hoplimit(dst));