Re: [PATCH v2] crypto: s390/phmac - Do not modify the req->nbytes value

[Holger Dengler <dengler@linux.ibm.com>]

On 14/10/2025 12:53, Harald Freudenberger wrote:
> The phmac implementation used the req->nbytes field on combined
> operations (finup, digest) to track the state:
> with req->nbytes > 0 the update needs to be processed,
> while req->nbytes == 0 means to do the final operation. For
> this purpose the req->nbytes field was set to 0 after successful
> update operation. However, aead uses the req->nbytes field after a
> successful hash operation to determine the amount of data to
> en/decrypt. So an implementation must not modify the nbytes field.
> 
> Fixed by a slight rework on the phmac implementation. There is
> now a new field async_op in the request context which tracks
> the (asynch) operation to process. So the 'state' via req->nbytes
> is not needed any more and now this field is untouched and may
> be evaluated even after a request is processed by the phmac
> implementation.
> 
> Fixes: cbbc675506cc ("crypto: s390 - New s390 specific protected key hash phmac")
> Reported-by: Ingo Franzki <ifranzki@linux.ibm.com>
> Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>

Reviewed-by: Holger Dengler <dengler@linux.ibm.com>

And please don't forget to pick Ingo's R-b and T-b tags (or let b4 do the job).

-- 
Mit freundlichen Grüßen / Kind regards
Holger Dengler
--
IBM Systems, Linux on IBM Z Development
dengler@linux.ibm.com