Hi Antoine, On 01.12.2017 11:24, Antoine Tenart wrote: > Hi Kamil, > > On Fri, Dec 01, 2017 at 11:18:30AM +0100, Kamil Konieczny wrote: >> On 01.12.2017 09:11, Antoine Tenart wrote: >>> - Other drivers are doing this check (grep "if (!req->result)" or >>> "if (req->result)" to see some of them). >>> - I see at least one commit fixing the exact same issue I'm facing here, >>> 393897c5156a415533ff85aa381458840417b032: >>> >>> crypto: ccp - Check for caller result area before using it >>> >>> For a hash operation, the caller doesn't have to supply a result >>> area on every call so don't use it / update it if it hasn't >>> been supplied. >> >> Do you set last_req true for digest/finup/final ? If yes, >> then you need to copy result only when it is true, >> >> if (sreq->last_req) { >> result_sz = crypto_ahash_digestsize(ahash); >> memcpy(sreq->state, areq->result, result_sz); >> } > > Yes the last_req flag is set for the last request, so when > digest/finup/final are called. But no we can't copy the result into the > state based on this as an user might want to perform multiple updates, > then export the context, to import it again before sending more updates. IMHO set them to false in hash update and init, set finish false and last_req true for hash final, and set both true for hash finup and digest. As Herbert tells in https://www.spinics.net/lists/linux-crypto/msg28658.html you should support scenario export + update/finup, so basically export is reading state but it do not halt your hash driver. -- Best regards, Kamil Konieczny Samsung R&D Institute Poland