ipv6: Honor all IPv6 PIO Valid Lifetime values
RFC4862 5.5.3 e) prevents received Router Advertisements from reducing the Valid Lifetime of configured addresses to less than two hours, thus preventing hosts from reacting to the information provided by a router that has positive knowledge that a prefix has become invalid. This patch makes hosts honor all Valid Lifetime values, as per draft-gont-6man-slaac-renum-06, Section 4.2. This is meant to help mitigate the problem discussed in draft-ietf-v6ops-slaac-renum. Note: Attacks aiming at disabling an advertised prefix via a Valid Lifetime of 0 are not really more harmful than other attacks that can be performed via forged RA messages, such as those aiming at completely disabling a next-hop router via an RA that advertises a Router Lifetime of 0, or performing a Denial of Service (DoS) attack by advertising illegitimate prefixes via forged PIOs. In scenarios where RA-based attacks are of concern, proper mitigations such as RA-Guard [RFC6105] [RFC7113] should be implemented. Signed-off-by:Fernando Gont <fgont@si6networks.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
30685b2a
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