On 11/14/21 11:40 AM, Sagi Grimberg wrote:

On 11/12/21 2:59 PM, Hannes Reinecke wrote:

quoted

Hi all,

recent updates to the NVMe spec have added definitions for in-band
authentication, and seeing that it provides some real benefit
especially for NVMe-TCP here's an attempt to implement it.

Tricky bit here is that the specification orients itself on TLS 1.3,
but supports only the FFDHE groups. Which of course the kernel doesn't
support. I've been able to come up with a patch for this, but as this
is my first attempt to fix anything in the crypto area I would invite
people more familiar with these matters to have a look.

Also note that this is just for in-band authentication. Secure
concatenation (ie starting TLS with the negotiated parameters) is not
implemented; one would need to update the kernel TLS implementation
for this, which at this time is beyond scope.

As usual, comments and reviews are welcome.

Changes to v4:
- Validate against blktest suite

Nice! thanks hannes, this is going to be very useful moving
forward.

Oh, definitely. The number of issue these tests found...

quoted

- Fixup base64 decoding

What was fixed up there?

The padding character '=' wasn't handled correctly on decoding (the 
character itself was skipped, by the 'bits' value wasn't increased, 
leading to a spurious error in decoding an any key longer than 32 bit 
not being accepted.

quoted

- Transform secret with correct hmac algorithm

Is that what I reported last time? Can you perhaps
point me to the exact patch that fixes this?

Well, no, not really; the patch itself got squashed in the main patches.
But problem here was that the key transformation from section 8.13.5.7 
had been using the hash algorithm from the initial challenge, not the 
one specified in the key itself.
This lead to decoding errors when using a key with a different length 
than the hash algorithm.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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