From e6f86b0f7ae473969a3301b74bf98af9e42ecd0e Mon Sep 17 00:00:00 2001 From: Virgile Jarry Date: Fri, 10 Aug 2018 17:48:15 +0200 Subject: ipv6: Add icmp_echo_ignore_all support for ICMPv6 Preventing the kernel from responding to ICMP Echo Requests messages can be useful in several ways. The sysctl parameter 'icmp_echo_ignore_all' can be used to prevent the kernel from responding to IPv4 ICMP echo requests. For IPv6 pings, such a sysctl kernel parameter did not exist. Add the ability to prevent the kernel from responding to IPv6 ICMP echo requests through the use of the following sysctl parameter : /proc/sys/net/ipv6/icmp/echo_ignore_all. Update the documentation to reflect this change. Signed-off-by: Virgile Jarry Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 5 +++++ include/net/netns/ipv6.h | 1 + include/uapi/linux/sysctl.h | 3 ++- net/ipv6/af_inet6.c | 1 + net/ipv6/icmp.c | 16 +++++++++++++--- 5 files changed, 22 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index e74515ecaa9c..8313a636dd53 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1882,6 +1882,11 @@ ratelimit - INTEGER otherwise the minimal space between responses in milliseconds. Default: 1000 +echo_ignore_all - BOOLEAN + If set non-zero, then the kernel will ignore all ICMP ECHO + requests sent to it over the IPv6 protocol. + 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 762ac9931b62..f0e396ab9bec 100644 --- a/include/net/netns/ipv6.h +++ b/include/net/netns/ipv6.h @@ -32,6 +32,7 @@ struct netns_sysctl_ipv6 { int flowlabel_consistency; int auto_flowlabels; int icmpv6_time; + int icmpv6_echo_ignore_all; int anycast_src_echo_reply; int ip_nonlocal_bind; int fwmark_reflect; diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 6b58371b1f0d..d71013fffaf6 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -575,7 +575,8 @@ enum { /* /proc/sys/net/ipv6/icmp */ enum { - NET_IPV6_ICMP_RATELIMIT=1 + NET_IPV6_ICMP_RATELIMIT = 1, + NET_IPV6_ICMP_ECHO_IGNORE_ALL = 2 }; /* /proc/sys/net//neigh/ */ diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 020f6e14a7af..673bba31eb18 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -832,6 +832,7 @@ static int __net_init inet6_net_init(struct net *net) net->ipv6.sysctl.bindv6only = 0; net->ipv6.sysctl.icmpv6_time = 1*HZ; + net->ipv6.sysctl.icmpv6_echo_ignore_all = 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 7f6b1f81c200..c9c53ade55c3 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -794,6 +794,7 @@ out: static int icmpv6_rcv(struct sk_buff *skb) { + struct net *net = dev_net(skb->dev); struct net_device *dev = skb->dev; struct inet6_dev *idev = __in6_dev_get(dev); const struct in6_addr *saddr, *daddr; @@ -843,7 +844,8 @@ static int icmpv6_rcv(struct sk_buff *skb) switch (type) { case ICMPV6_ECHO_REQUEST: - icmpv6_echo_reply(skb); + if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) + icmpv6_echo_reply(skb); break; case ICMPV6_ECHO_REPLY: @@ -1104,6 +1106,13 @@ static struct ctl_table ipv6_icmp_table_template[] = { .mode = 0644, .proc_handler = proc_dointvec_ms_jiffies, }, + { + .procname = "echo_ignore_all", + .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, { }, }; @@ -1115,9 +1124,10 @@ struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) sizeof(ipv6_icmp_table_template), GFP_KERNEL); - if (table) + if (table) { table[0].data = &net->ipv6.sysctl.icmpv6_time; - + table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; + } return table; } #endif -- cgit v1.2.3-59-g8ed1b