Re: [PATCH net-next] ipv6: Honor all IPv6 PIO Valid Lifetime values

[David Miller <davem@davemloft.net>]

From: Fernando Gont <fgont@si6networks.com>
Date: Sun, 19 Apr 2020 09:24:57 -0300

> 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>

Applied, thank you.