From: David Howells <dhowells@redhat.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: dhowells@redhat.com, Bruce Fields <bfields@fieldses.org>,
Chuck Lever <chuck.lever@oracle.com>,
CIFS <linux-cifs@vger.kernel.org>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
"open list:BPF JIT for MIPS (32-BIT AND 64-BIT)"
<netdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Trond Myklebust <trond.myklebust@hammerspace.com>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org
Subject: Re: Why the auxiliary cipher in gss_krb5_crypto.c?
Date: Mon, 07 Dec 2020 12:01:52 +0000 [thread overview]
Message-ID: <468625.1607342512@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAMj1kXFe50HvZLxG6Kh-oYBCf5uu51hhuh7mW5UQ62ZSqmu_xA@mail.gmail.com>
Ard Biesheuvel <ardb@kernel.org> wrote:
> > Yeah - the problem with that is that for sunrpc, we might be dealing with 1MB
> > plus bits of non-contiguous pages, requiring >8K of scatterlist elements
> > (admittedly, we can chain them, but we may have to do one or more large
> > allocations).
> >
> > > However, I would recommend against it:
> >
> > Sorry, recommend against what?
> >
>
> Recommend against the current approach of manipulating the input like
> this and feeding it into the skcipher piecemeal.
Right. I understand the problem, but as I mentioned above, the scatterlist
itself becomes a performance issue as it may exceed two pages in size. Double
that as there may need to be separate input and output scatterlists.
> Herbert recently made some changes for MSG_MORE support in the AF_ALG
> code, which permits a skcipher encryption to be split into several
> invocations of the skcipher layer without the need for this complexity
> on the side of the caller. Maybe there is a way to reuse that here.
> Herbert?
I wonder if it would help if the input buffer and output buffer didn't have to
correspond exactly in usage - ie. the output buffer could be used at a slower
rate than the input to allow for buffering inside the crypto algorithm.
> > Can you also do SHA at the same time in the same loop?
>
> SHA-1 or HMAC-SHA1? The latter could probably be modeled as an AEAD.
> The former doesn't really fit the current API so we'd have to invent
> something for it.
The hashes corresponding to the kerberos enctypes I'm supporting are:
HMAC-SHA1 for aes128-cts-hmac-sha1-96 and aes256-cts-hmac-sha1-96.
HMAC-SHA256 for aes128-cts-hmac-sha256-128
HMAC-SHA384 for aes256-cts-hmac-sha384-192
CMAC-CAMELLIA for camellia128-cts-cmac and camellia256-cts-cmac
I'm not sure you can support all of those with the instructions available.
David
next prev parent reply other threads:[~2020-12-07 12:03 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 12:57 [RFC][PATCH 00/18] crypto: Add generic Kerberos library David Howells
2020-11-12 12:57 ` [PATCH 01/18] crypto/krb5: Implement Kerberos crypto core David Howells
2020-11-12 12:58 ` [PATCH 02/18] crypto/krb5: Add some constants out of sunrpc headers David Howells
2020-11-12 12:58 ` [PATCH 03/18] crypto/krb5: Provide infrastructure and key derivation David Howells
2020-11-12 12:58 ` [PATCH 04/18] crypto/krb5: Implement the Kerberos5 rfc3961 " David Howells
2020-11-12 12:58 ` [PATCH 05/18] crypto/krb5: Implement the Kerberos5 rfc3961 encrypt and decrypt functions David Howells
2020-11-12 12:58 ` [PATCH 06/18] crypto/krb5: Implement the Kerberos5 rfc3961 get_mic and verify_mic David Howells
2020-11-12 12:58 ` [PATCH 07/18] crypto/krb5: Implement the AES enctypes from rfc3962 David Howells
2020-11-12 12:58 ` [PATCH 08/18] crypto/krb5: Implement crypto self-testing David Howells
2020-11-12 12:58 ` [PATCH 09/18] crypto/krb5: Implement the AES enctypes from rfc8009 David Howells
2020-11-12 12:59 ` [PATCH 10/18] crypto/krb5: Implement the AES encrypt/decrypt " David Howells
2020-11-12 12:59 ` [PATCH 11/18] crypto/krb5: Add the AES self-testing data " David Howells
2020-11-12 12:59 ` [PATCH 12/18] crypto/krb5: Implement the Camellia enctypes from rfc6803 David Howells
2020-11-12 12:59 ` [PATCH 13/18] rxrpc: Add the security index for yfs-rxgk David Howells
2020-11-12 12:59 ` [PATCH 14/18] rxrpc: Add YFS RxGK (GSSAPI) security class David Howells
2020-11-12 12:59 ` [PATCH 15/18] rxrpc: rxgk: Provide infrastructure and key derivation David Howells
2020-11-12 12:59 ` [PATCH 16/18] rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI) David Howells
2020-11-12 13:00 ` [PATCH 17/18] rxrpc: rxgk: Implement connection rekeying David Howells
2020-11-12 13:00 ` [PATCH 18/18] rxgk: Support OpenAFS's rxgk implementation David Howells
2020-11-12 13:44 ` [RFC][PATCH 00/18] crypto: Add generic Kerberos library David Howells
2020-11-12 14:36 ` Chuck Lever
2020-11-12 15:42 ` David Howells
2020-11-12 15:49 ` Chuck Lever
2020-11-12 16:54 ` David Howells
2020-11-12 21:07 ` Bruce Fields
2020-11-12 21:09 ` Chuck Lever
2020-11-12 18:37 ` J. Bruce Fields
2020-11-12 18:39 ` Chuck Lever
2020-11-26 6:33 ` Herbert Xu
2020-11-26 8:19 ` David Howells
2020-11-27 5:07 ` Herbert Xu
2020-12-01 8:44 ` David Howells
2020-12-01 8:46 ` Herbert Xu
2020-12-01 9:12 ` David Howells
2020-12-01 10:36 ` Herbert Xu
2020-12-04 14:59 ` Why the auxiliary cipher in gss_krb5_crypto.c? David Howells
2020-12-04 15:46 ` Bruce Fields
2020-12-04 16:05 ` Chuck Lever
2020-12-04 16:14 ` Bruce Fields
2020-12-04 16:01 ` David Howells
2020-12-04 16:03 ` Bruce Fields
2020-12-04 16:50 ` David Howells
2020-12-04 17:06 ` Ard Biesheuvel
2020-12-04 17:19 ` David Howells
2020-12-04 17:35 ` Ard Biesheuvel
2020-12-04 21:08 ` Herbert Xu
2020-12-07 8:24 ` David Howells
2020-12-07 12:01 ` David Howells [this message]
2020-12-07 13:08 ` Ard Biesheuvel
2020-12-07 14:15 ` David Howells
2020-12-08 8:27 ` Ard Biesheuvel
2020-12-08 9:18 ` David Howells
2020-12-04 18:13 ` Theodore Y. Ts'o
2020-12-08 13:25 ` David Howells
2020-12-08 14:04 ` Ard Biesheuvel
2020-12-08 14:13 ` David Howells
2020-12-08 14:02 ` David Howells
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