From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [kernel-hardening] Re: [PATCH v7 3/6] random: use SipHash in
 place of MD5
Date: Thu, 22 Dec 2016 16:29:14 +0100
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On Thu, Dec 22, 2016 at 4:12 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> As a first step, I'm considering adding a patch to move halfmd4.c
> inside the ext4 domain, or at the very least, simply remove it from
> linux/cryptohash.h. That'll then leave the handful of bizarre sha1
> usages to consider.

Specifically something like this:

https://git.zx2c4.com/linux-dev/commit/?h=siphash&id=978213351f9633bd1e3d1fdc3f19d28e36eeac90

That only leaves two more uses of "cryptohash" to consider, but they
require a bit of help. First, sha_transform in net/ipv6/addrconf.c.
That might be a straight-forward conversion to SipHash, but perhaps
not; I need to look closely and think about it. The next is
sha_transform in kernel/bpf/core.c. I really have no idea what's going
on with the eBPF stuff, so that will take a bit longer to study. Maybe
sha1 is fine in the end there? I'm not sure yet.