From 3985e8a3611a93bb36789f65db862e5700aab65e Mon Sep 17 00:00:00 2001 From: Erik Kline Date: Wed, 22 Jul 2015 16:38:25 +0900 Subject: ipv6: sysctl to restrict candidate source addresses Per RFC 6724, section 4, "Candidate Source Addresses": It is RECOMMENDED that the candidate source addresses be the set of unicast addresses assigned to the interface that will be used to send to the destination (the "outgoing" interface). Add a sysctl to enable this behaviour. Signed-off-by: Erik Kline Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 7 +++++++ include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 22 +++++++++++++++++++--- 4 files changed, 28 insertions(+), 3 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index f63aeefd2c24..1a5ab21bcca5 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1460,6 +1460,13 @@ router_solicitations - INTEGER routers are present. Default: 3 +use_oif_addrs_only - BOOLEAN + When enabled, the candidate source addresses for destinations + routed via this interface are restricted to the set of addresses + configured on this interface (vis. RFC 6724, section 4). + + Default: false + use_tempaddr - INTEGER Preference for Privacy Extensions (RFC3041). <= 0 : disable Privacy Extensions diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 1319a6bb6b82..06ed637225b8 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -57,6 +57,7 @@ struct ipv6_devconf { bool initialized; struct in6_addr secret; } stable_secret; + __s32 use_oif_addrs_only; void *sysctl; }; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 5efa54ae567c..641a146ead7d 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -171,6 +171,7 @@ enum { DEVCONF_USE_OPTIMISTIC, DEVCONF_ACCEPT_RA_MTU, DEVCONF_STABLE_SECRET, + DEVCONF_USE_OIF_ADDRS_ONLY, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 32153c248959..eb0c6a3a8a00 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -211,7 +211,8 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_ra_mtu = 1, .stable_secret = { .initialized = false, - } + }, + .use_oif_addrs_only = 0, }; static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { @@ -253,6 +254,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .stable_secret = { .initialized = false, }, + .use_oif_addrs_only = 0, }; /* Check if a valid qdisc is available */ @@ -1472,11 +1474,16 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev, * include addresses assigned to interfaces * belonging to the same site as the outgoing * interface.) + * - "It is RECOMMENDED that the candidate source addresses + * be the set of unicast addresses assigned to the + * interface that will be used to send to the destination + * (the 'outgoing' interface)." (RFC 6724) */ if (dst_dev) { + idev = __in6_dev_get(dst_dev); if ((dst_type & IPV6_ADDR_MULTICAST) || - dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL) { - idev = __in6_dev_get(dst_dev); + dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL || + (idev && idev->cnf.use_oif_addrs_only)) { use_oif_addr = true; } } @@ -4607,6 +4614,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local; array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu; /* we omit DEVCONF_STABLE_SECRET for now */ + array[DEVCONF_USE_OIF_ADDRS_ONLY] = cnf->use_oif_addrs_only; } static inline size_t inet6_ifla6_size(void) @@ -5605,6 +5613,14 @@ static struct addrconf_sysctl_table .mode = 0600, .proc_handler = addrconf_sysctl_stable_secret, }, + { + .procname = "use_oif_addrs_only", + .data = &ipv6_devconf.use_oif_addrs_only, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + + }, { /* sentinel */ } -- cgit v1.2.3-58-ga151