Re: [PATCH net-next v5 00/11] ipv6: Only create RTF_CACHE route after encountering pmtu exception

From: Alexander Holler
Date: Mon Aug 17 2015 - 05:44:07 EST


Am 15.08.2015 um 09:48 schrieb Alexander Holler:
Am 30.07.2015 um 13:57 schrieb Alexander Holler:
Am 29.07.2015 um 11:25 schrieb Alexander Holler:
Am 23.05.2015 um 05:55 schrieb Martin KaFai Lau:

To complete the discussion, that "annoying behaviour" is also a big
information leak.

Because routes aren't considered confidential and aren't subject to
privacy, that broken behaviour enabled *everyone* on the same system to
see *all* the remote IPv6 systems to which there have been connection
establishment tries.

Just in case I haven't described the problem I see clearly enough:

"Everyone" means everything (other SW) too, and if "Happy_Eyeballs" algorithms are used (see RFC 6555), this also affects systems which only have an IPv4 connection to the world, as long as IPv6 is enabled.

That means it does not only affect multiuser systems and the current behaviour of kernels < 4.2 renders e.g. the private mode of most browsers somewhat useless too (in regard to protection against other SW and/or users running on the same system).

That's why I vote to check out if it's possible/reasonable to backport this series to the stable kernels.

Regards,

Alexander Holler
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