3.2.69-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: "D.S. Ljungmark" <[email protected]> commit 6fd99094de2b83d1d4c8457f2c83483b2828e75a upstream. A local route may have a lower hop_limit set than global routes do. RFC 3756, Section 4.2.7, "Parameter Spoofing" > 1. The attacker includes a Current Hop Limit of one or another small > number which the attacker knows will cause legitimate packets to > be dropped before they reach their destination. > As an example, one possible approach to mitigate this threat is to > ignore very small hop limits. The nodes could implement a > configurable minimum hop limit, and ignore attempts to set it below > said limit. Signed-off-by: D.S. Ljungmark <[email protected]> Acked-by: Hannes Frederic Sowa <[email protected]> Signed-off-by: David S. Miller <[email protected]> [bwh: Backported to 3.2: adjust ND_PRINTK() usage] Signed-off-by: Ben Hutchings <[email protected]> --- net/ipv6/ndisc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1277,7 +1277,14 @@ static void ndisc_router_discovery(struc rt->rt6i_expires = jiffies + (HZ * lifetime); if (ra_msg->icmph.icmp6_hop_limit) { - in6_dev->cnf.hop_limit = 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) { + in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit; + } else { + ND_PRINTK2(KERN_WARNING "RA: Got route advertisement with lower hop_limit than current\n"); + } if (rt) dst_metric_set(&rt->dst, RTAX_HOPLIMIT, ra_msg->icmph.icmp6_hop_limit); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
