Am Donnerstag, 15. Februar 2018, 06:30:36 CET schrieb Harsh Jain: Hi Harsh,
> On 14-02-2018 18:22, Stephan Mueller wrote: > > Am Mittwoch, 14. Februar 2018, 06:43:53 CET schrieb Harsh Jain: > > > > Hi Harsh, > > > >> Patch set is working fine with chelsio Driver. > > > > Thank you. > > > >> Do we really need IV locking mechanism for AEAD algo because AEAD algo's > >> don't support Partial mode operation and Driver are not updating(atleast > >> Chelsio) IV's on AEAD request completions. > > > > Yes, I think we would need it. It is technically possible to have multiple > > IOCBs for AEAD ciphers. Even though your implementation may not write the > > IV back, others may do that. At least I do not see a guarantee that the > > IV is *not* written back by a driver. > > There is no use of writing IV back in AEAD algo till Framework starts > supporting Partial mode. I agree. > Even if Driver starts updating IV for AEAD, > Multiple IOCB's in both cases will yield wrong results only. This would only be the case if the driver would not implicitly or explicitly serialize the requests. > > Case 1 : If we have AEAD IV serialization applied, Encryption will be > wrong if same IV gets used. Agreed. > Case 2: If we do not have IV serialization for > AEAD. Encryption will be fine but user will have multiple Authentication > tag (that too with final block processed). Its like 2nd Block encryption > is based on IV received from 1st block and Authentication Tag value is > based on 2nd block content only. Agreed. But are we sure that all drivers behave correctly? Before you notified us of the issue, I was not even aware of the fact that this serialization may not be done in the driver. And we only have seen that issue with AF_ALG where we test for multiple concurrent AIO operations. Besides, when we do not have the locking for AEAD, what would we gain: one less lock to take vs. guarantee that the AEAD operation is always properly serialized. Ciao Stephan
