> -----Original Message----- > From: Corentin Labbe <clabbe.montj...@gmail.com> > Sent: Friday, August 2, 2019 7:19 AM > To: Pascal Van Leeuwen <pvanleeu...@verimatrix.com> > Cc: herb...@gondor.apana.org.au; linux-crypto@vger.kernel.org; linux- > ker...@vger.kernel.org > Subject: Re: Need help with failling gcm_base(ctr,ghash-generic) selftest > > On Fri, Aug 02, 2019 at 12:24:04AM +0000, Pascal Van Leeuwen wrote: > > > -----Original Message----- > > > From: linux-crypto-ow...@vger.kernel.org > > > <linux-crypto-ow...@vger.kernel.org> On > Behalf Of > > > Corentin Labbe > > > Sent: Thursday, August 1, 2019 9:43 PM > > > To: herb...@gondor.apana.org.au; linux-crypto@vger.kernel.org > > > Cc: linux-ker...@vger.kernel.org > > > Subject: Need help with failling gcm_base(ctr,ghash-generic) selftest > > > > > > Hello > > > > > > I am writing the Allwinner sun8i-ce driver and when running tcrypt I got > > > [ 30.201739] alg: aead: gcm_base(ctr-aes-sun8i-ce,ghash-generic) > > > decryption failed > on test > > > vector 3; expected_error=0, actual_error=-74, cfg=\"random: may_sleep > > > use_digest > > > src_divs=[100.0%@+2614] dst_divs=[5.90%@alignmask+3015, 60.56%@+3996, > > > 17.92%@+865, > > > 15.62%@+10]\" > > > or > > > > > The decryption reports only an -EBADMSG here, which means the decryption > > itself went > > fine, but the authentication tag mismatched. > > > > > > > [ 148.613537] alg: aead: gcm_base(ctr-aes-sun8i-ce,ghash-generic) > > > encryption test > failed > > > (wrong result) on test vector 2, cfg=\"random: may_sleep use_final > src_divs=[100.0%@+0] > > > iv_offset=20\" > > > > > Can't say for sure, but considering the decrypt error, this is most likely > > just a > > mismatch on the appended authentication tag. > > > > > Since ctr-aes-sun8i-ce is passing the ctr(aes) selftest, I dont > > > understand what could > be > > > wrong. > > > > > That is possible, as this appears to be a problem with the authentication > > part, > > not the encryption part. So possibly a problem with the way you setup the > > authentication key (which is actually derived from the encryption key, but > > I don't > > know if your hardware does this autonomously, mine doesn't) and/or > > operation? > > > > But since my driver is just a skcipher, I dont understand why I should care > about any aead > part, right ? > Ah, my bad ... your aes-ctr skcipher is being wrapped by the generic gcm_base template here, I missed that detail ... wish I could help you further, but I can't think of anything obvious that could cause this (decrypt fails on auth as I remarked earlier but only with a specific scatter buffer layout??).
Regards, Pascal van Leeuwen Silicon IP Architect, Multi-Protocol Engines @ Verimatrix www.insidesecure.com
