diff options
| author | Hangbin Liu <liuhangbin@gmail.com> | 2015-07-30 14:28:42 +0800 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-03-04 10:25:48 -0500 |
| commit | d07f3017baa86b3e44eff41a41e3b297604ac8fb (patch) | |
| tree | bc8b041ffdfdde78526824c097ecd45317d835ac /net | |
| parent | d04aa950dbd249222f87c96fac9c547890524f5a (diff) | |
net/ipv6: add sysctl option accept_ra_min_hop_limit
[ Upstream commit 8013d1d7eafb0589ca766db6b74026f76b7f5cb4 ]
Commit 6fd99094de2b ("ipv6: Don't reduce hop limit for an interface")
disabled accept hop limit from RA if it is smaller than the current hop
limit for security stuff. But this behavior kind of break the RFC definition.
RFC 4861, 6.3.4. Processing Received Router Advertisements
A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time,
and Retrans Timer) may contain a value denoting that it is
unspecified. In such cases, the parameter should be ignored and the
host should continue using whatever value it is already using.
If the received Cur Hop Limit value is non-zero, the host SHOULD set
its CurHopLimit variable to the received value.
So add sysctl option accept_ra_min_hop_limit to let user choose the minimum
hop limit value they can accept from RA. And set default to 1 to meet RFC
standards.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/addrconf.c | 10 | ||||
| -rw-r--r-- | net/ipv6/ndisc.c | 16 |
2 files changed, 17 insertions, 9 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index f4795b0d6e6e..28c4bc58f2cc 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -195,6 +195,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, .accept_ra_from_local = 0, + .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -236,6 +237,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, .accept_ra_from_local = 0, + .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -4565,6 +4567,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor; array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses; array[DEVCONF_ACCEPT_RA_DEFRTR] = cnf->accept_ra_defrtr; + array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] = cnf->accept_ra_min_hop_limit; array[DEVCONF_ACCEPT_RA_PINFO] = cnf->accept_ra_pinfo; #ifdef CONFIG_IPV6_ROUTER_PREF array[DEVCONF_ACCEPT_RA_RTR_PREF] = cnf->accept_ra_rtr_pref; @@ -5458,6 +5461,13 @@ static struct addrconf_sysctl_table .proc_handler = proc_dointvec, }, { + .procname = "accept_ra_min_hop_limit", + .data = &ipv6_devconf.accept_ra_min_hop_limit, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { .procname = "accept_ra_pinfo", .data = &ipv6_devconf.accept_ra_pinfo, .maxlen = sizeof(int), diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 96f153c0846b..abb0bdda759a 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1225,18 +1225,16 @@ static void ndisc_router_discovery(struct sk_buff *skb) if (rt) rt6_set_expires(rt, jiffies + (HZ * lifetime)); - if (ra_msg->icmph.icmp6_hop_limit) { - /* Only set hop_limit on the interface if it is higher than - * the current hop_limit. - */ - if (in6_dev->cnf.hop_limit < ra_msg->icmph.icmp6_hop_limit) { + if (in6_dev->cnf.accept_ra_min_hop_limit < 256 && + ra_msg->icmph.icmp6_hop_limit) { + if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) { in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit; + if (rt) + dst_metric_set(&rt->dst, RTAX_HOPLIMIT, + ra_msg->icmph.icmp6_hop_limit); } else { - ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than current\n"); + ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n"); } - if (rt) - dst_metric_set(&rt->dst, RTAX_HOPLIMIT, - ra_msg->icmph.icmp6_hop_limit); } skip_defrtr: |