[tor-dev] SipHash Impact on TCP ISN skew fingerprinting

Yawning Angel yawning at schwanenlied.me
Wed Jan 11 21:45:09 UTC 2017


On Wed, 11 Jan 2017 19:57:07 +0100
bancfc at openmailbox.org wrote:
> Its my guess that that timer values added in ISNs should now be 
> indistinguishable from the rest of the hashed secret outlined in 
> RFC-6528.[1] Can anyone knowledgeable in reading kernel code [2]
> please confirm that this kills clock skew extraction [3] and
> fingerprinting [4] described in Steven Murdoch's papers?

The issue isn't the choice of the hash algorithm, and the patch
doesn't change net/core/secure_seq.c:seq_scale() at all, nor how/when
it's called.

So no, it doesn't fix the issue.

Regards,

-- 
Yawning Angel
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