Re: [RFC PATCH 4.10 0/6] Switch BPF's digest to SHA256

Andy Lutomirski [off-list ref] wrote:

Since there are plenty of uses for the new-in-4.10 BPF digest feature
that would be problematic if malicious users could produce collisions,
the BPF digest should be collision-resistant.  SHA-1 is no longer
considered collision-resistant, so switch it to SHA-256.

The actual switchover is trivial.  Most of this series consists of
cleanups to the SHA256 code to make it usable as a standalone library
(since BPF should not depend on crypto).

The cleaned up library is much more user-friendly than the SHA-1 code,
so this also significantly tidies up the BPF digest code.

This is intended for 4.10.  If this series misses 4.10 and nothing
takes its place, then we'll have an unpleasant ABI stability
situation.

Can you please explain why BPF needs to be able to use SHA directly
rather than through the crypto API?

Thanks,
-- 
Email: Herbert Xu [off-list ref]
Home Page: http://gondor.apana.org.au/~herbert/
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