From bbea124bc99df968011e76eba105fe964a4eceab Mon Sep 17 00:00:00 2001 From: Joel Scherpelz Date: Wed, 22 Mar 2017 18:19:04 +0900 Subject: [PATCH] net: ipv6: Add sysctl for minimum prefix len acceptable in RIOs. This commit adds a new sysctl accept_ra_rt_info_min_plen that defines the minimum acceptable prefix length of Route Information Options. The new sysctl is intended to be used together with accept_ra_rt_info_max_plen to configure a range of acceptable prefix lengths. It is useful to prevent misconfigurations from unintentionally blackholing too much of the IPv6 address space (e.g., home routers announcing RIOs for fc00::/7, which is incorrect). Signed-off-by: Joel Scherpelz Acked-by: Lorenzo Colitti Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 13 +++++++++++-- include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + include/uapi/linux/sysctl.h | 1 + net/ipv6/addrconf.c | 10 ++++++++++ net/ipv6/ndisc.c | 2 ++ 6 files changed, 26 insertions(+), 2 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index b57308e76b1d..eaee2c8d4c00 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1461,11 +1461,20 @@ accept_ra_pinfo - BOOLEAN Functional default: enabled if accept_ra is enabled. disabled if accept_ra is disabled. +accept_ra_rt_info_min_plen - INTEGER + Minimum prefix length of Route Information in RA. + + Route Information w/ prefix smaller than this variable shall + be ignored. + + Functional default: 0 if accept_ra_rtr_pref is enabled. + -1 if accept_ra_rtr_pref is disabled. + accept_ra_rt_info_max_plen - INTEGER Maximum prefix length of Route Information in RA. - Route Information w/ prefix larger than or equal to this - variable shall be ignored. + Route Information w/ prefix larger than this variable shall + be ignored. Functional default: 0 if accept_ra_rtr_pref is enabled. -1 if accept_ra_rtr_pref is disabled. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index f0d79bd054ca..e1b442996f81 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -37,6 +37,7 @@ struct ipv6_devconf { __s32 accept_ra_rtr_pref; __s32 rtr_probe_interval; #ifdef CONFIG_IPV6_ROUTE_INFO + __s32 accept_ra_rt_info_min_plen; __s32 accept_ra_rt_info_max_plen; #endif #endif diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index d8f6a1ac9af4..2ae59178189d 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -184,6 +184,7 @@ enum { DEVCONF_ENHANCED_DAD, DEVCONF_ADDR_GEN_MODE, DEVCONF_DISABLE_POLICY, + DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, DEVCONF_MAX }; diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index d2b12152e358..e13d48058b8d 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -568,6 +568,7 @@ enum { NET_IPV6_PROXY_NDP=23, NET_IPV6_ACCEPT_SOURCE_ROUTE=25, NET_IPV6_ACCEPT_RA_FROM_LOCAL=26, + NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN=27, __NET_IPV6_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 8c69768a5c46..dff5beb26a01 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -224,6 +224,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_ra_rtr_pref = 1, .rtr_probe_interval = 60 * HZ, #ifdef CONFIG_IPV6_ROUTE_INFO + .accept_ra_rt_info_min_plen = 0, .accept_ra_rt_info_max_plen = 0, #endif #endif @@ -277,6 +278,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .accept_ra_rtr_pref = 1, .rtr_probe_interval = 60 * HZ, #ifdef CONFIG_IPV6_ROUTE_INFO + .accept_ra_rt_info_min_plen = 0, .accept_ra_rt_info_max_plen = 0, #endif #endif @@ -4979,6 +4981,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_RTR_PROBE_INTERVAL] = jiffies_to_msecs(cnf->rtr_probe_interval); #ifdef CONFIG_IPV6_ROUTE_INFO + array[DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN] = cnf->accept_ra_rt_info_min_plen; array[DEVCONF_ACCEPT_RA_RT_INFO_MAX_PLEN] = cnf->accept_ra_rt_info_max_plen; #endif #endif @@ -6121,6 +6124,13 @@ static const struct ctl_table addrconf_sysctl[] = { .proc_handler = proc_dointvec_jiffies, }, #ifdef CONFIG_IPV6_ROUTE_INFO + { + .procname = "accept_ra_rt_info_min_plen", + .data = &ipv6_devconf.accept_ra_rt_info_min_plen, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, { .procname = "accept_ra_rt_info_max_plen", .data = &ipv6_devconf.accept_ra_rt_info_max_plen, diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 112ccbc0a8ac..b5812b3f7539 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1418,6 +1418,8 @@ static void ndisc_router_discovery(struct sk_buff *skb) if (ri->prefix_len == 0 && !in6_dev->cnf.accept_ra_defrtr) continue; + if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen) + continue; if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen) continue; rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3, -- GitLab