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Date: Wed, 20 Mar 2019 10:29:27 -0400
From: Stephen Suryaputra <ssuryaextr@...il.com>
To: netdev@...r.kernel.org
Cc: Stephen Suryaputra <ssuryaextr@...il.com>
Subject: [PATCH net-next] ipv6: Add icmp_echo_ignore_anycast for ICMPv6
In addition to icmp_echo_ignore_multicast, there is a need to also
prevent responding to pings to anycast addresses for security.
Signed-off-by: Stephen Suryaputra <ssuryaextr@...il.com>
---
Documentation/networking/ip-sysctl.txt | 5 +++++
include/net/netns/ipv6.h | 1 +
net/ipv6/af_inet6.c | 1 +
net/ipv6/icmp.c | 16 ++++++++++++++--
4 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 55ea7def46be..bd029fc55ccb 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1923,6 +1923,11 @@ echo_ignore_multicast - BOOLEAN
requests sent to it over the IPv6 protocol via multicast.
Default: 0
+echo_ignore_anycast - BOOLEAN
+ If set non-zero, then the kernel will ignore all ICMP ECHO
+ requests sent to it over the IPv6 protocol destined to anycast address.
+ Default: 0
+
xfrm6_gc_thresh - INTEGER
The threshold at which we will start garbage collecting for IPv6
destination cache entries. At twice this value the system will
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index e29aff15acc9..64e29b58bb5e 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -34,6 +34,7 @@ struct netns_sysctl_ipv6 {
int icmpv6_time;
int icmpv6_echo_ignore_all;
int icmpv6_echo_ignore_multicast;
+ int icmpv6_echo_ignore_anycast;
int anycast_src_echo_reply;
int ip_nonlocal_bind;
int fwmark_reflect;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index fdc117de849c..fa6b404cbd10 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -848,6 +848,7 @@ static int __net_init inet6_net_init(struct net *net)
net->ipv6.sysctl.icmpv6_time = 1*HZ;
net->ipv6.sysctl.icmpv6_echo_ignore_all = 0;
net->ipv6.sysctl.icmpv6_echo_ignore_multicast = 0;
+ net->ipv6.sysctl.icmpv6_echo_ignore_anycast = 0;
net->ipv6.sysctl.flowlabel_consistency = 1;
net->ipv6.sysctl.auto_flowlabels = IP6_DEFAULT_AUTO_FLOW_LABELS;
net->ipv6.sysctl.idgen_retries = 3;
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 0907bcede5e5..cc14b9998941 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -683,6 +683,7 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
struct dst_entry *dst;
struct ipcm6_cookie ipc6;
u32 mark = IP6_REPLY_MARK(net, skb->mark);
+ bool acast;
if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
@@ -690,9 +691,12 @@ static void icmpv6_echo_reply(struct sk_buff *skb)
saddr = &ipv6_hdr(skb)->daddr;
+ acast = ipv6_anycast_destination(skb_dst(skb), saddr);
+ if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast)
+ return;
+
if (!ipv6_unicast_destination(skb) &&
- !(net->ipv6.sysctl.anycast_src_echo_reply &&
- ipv6_anycast_destination(skb_dst(skb), saddr)))
+ !(net->ipv6.sysctl.anycast_src_echo_reply && acast))
saddr = NULL;
memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
@@ -1126,6 +1130,13 @@ static struct ctl_table ipv6_icmp_table_template[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "echo_ignore_anycast",
+ .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{ },
};
@@ -1141,6 +1152,7 @@ struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
table[0].data = &net->ipv6.sysctl.icmpv6_time;
table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
+ table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast;
}
return table;
}
--
2.17.1
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