From f1b8fa9fa5865c58c093cde6d782104c22df9088 Mon Sep 17 00:00:00 2001 From: Andreas Roeseler Date: Mon, 29 Mar 2021 18:45:29 -0700 Subject: [PATCH] net: add sysctl for enabling RFC 8335 PROBE messages Section 8 of RFC 8335 specifies potential security concerns of responding to PROBE requests, and states that nodes that support PROBE functionality MUST be able to enable/disable responses and that responses MUST be disabled by default Signed-off-by: Andreas Roeseler Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.rst | 6 ++++++ include/net/netns/ipv4.h | 1 + net/ipv4/sysctl_net_ipv4.c | 9 +++++++++ 3 files changed, 16 insertions(+) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index c7952ac5bd2f1..4130bce40765c 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1143,6 +1143,12 @@ icmp_echo_ignore_all - BOOLEAN Default: 0 +icmp_echo_enable_probe - BOOLEAN + If set to one, then the kernel will respond to RFC 8335 PROBE + requests sent to it. + + Default: 0 + icmp_echo_ignore_broadcasts - BOOLEAN If set non-zero, then the kernel will ignore all ICMP ECHO and TIMESTAMP requests sent to it via broadcast/multicast. diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index d377266d133f0..9c8dd424d79b1 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -84,6 +84,7 @@ struct netns_ipv4 { #endif u8 sysctl_icmp_echo_ignore_all; + u8 sysctl_icmp_echo_enable_probe; u8 sysctl_icmp_echo_ignore_broadcasts; u8 sysctl_icmp_ignore_bogus_error_responses; u8 sysctl_icmp_errors_use_inbound_ifaddr; diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 3a7e5cf5d6cc7..e3cb2d96b55e9 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -598,6 +598,15 @@ static struct ctl_table ipv4_net_table[] = { .mode = 0644, .proc_handler = proc_dou8vec_minmax, }, + { + .procname = "icmp_echo_enable_probe", + .data = &init_net.ipv4.sysctl_icmp_echo_enable_probe, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE + }, { .procname = "icmp_echo_ignore_broadcasts", .data = &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts, -- 2.39.5