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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 2 deletions

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;
 }