netdev - Re: [RFC PATCH 03/24] crypto: Add 'krb5enc' hash and cipher AEAD algorithm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1215834.1737404294@warthog.procyon.org.uk>
Date: Mon, 20 Jan 2025 20:18:14 +0000
From: David Howells <dhowells@...hat.com>
To: Eric Biggers <ebiggers@...nel.org>
Cc: dhowells@...hat.com, Simon Horman <horms@...nel.org>,
    Herbert Xu <herbert@...dor.apana.org.au>,
    Chuck Lever <chuck.lever@...cle.com>,
    Trond Myklebust <trond.myklebust@...merspace.com>,
    "David S. Miller" <davem@...emloft.net>,
    Marc Dionne <marc.dionne@...istor.com>,
    Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
    Paolo Abeni <pabeni@...hat.com>, Ard Biesheuvel <ardb@...nel.org>,
    linux-crypto@...r.kernel.org, linux-afs@...ts.infradead.org,
    linux-nfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
    netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 03/24] crypto: Add 'krb5enc' hash and cipher AEAD algorithm

Eric Biggers <ebiggers@...nel.org> wrote:

> In any case, why would you need anything to do asynchronous at all here?

Because authenc, which I copied, passes the asynchronocity mode onto the two
algos it runs (one encrypt, one hash).  If authenc is run synchronously, then
the algos are run synchronously and serially; but if authenc is run async,
then the algos are run asynchronously - but they may still have to be run
serially[*] and the second is dispatched from the completion handler of the
first.  So two different paths through the code exist, and rxgk and testmgr
only test the synchronous path.

[*] Because in authenc-compatible encoding types, the output of the encryption
is hashed.  Older krb5 encodings hash the plaintext and the hash generation
and the encrypt can be run in parallel.  For decrypting, the reverse is true;
authenc may be able to do the decrypt and the hash in parallel...  But
parallellisation also requires that the input and output buffers are not the
same.

Anyway.  If it can be done asynchronously, that should probably be tested.

David