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Commit 0b03a5ca authored by Stephen Suryaputra's avatar Stephen Suryaputra Committed by David S. Miller
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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: default avatarStephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a534ea30

Documentation/networking/ip-sysctl.txt

+5 −0
Original line number Diff line number Diff line
@@ -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

include/net/netns/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

net/ipv6/af_inet6.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

net/ipv6/icmp.c

+14 −2
Original line number Diff line number Diff line
@@ -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;

}