From 0b03a5ca8b14321366eec4a903922d2b46d585ff Mon Sep 17 00:00:00 2001 From: Stephen Suryaputra Date: Wed, 20 Mar 2019 10:29:27 -0400 Subject: 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 Signed-off-by: David S. Miller --- 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; } -- cgit v1.2.3-59-g8ed1b