Hi Daniel, On Fri, Mar 15, 2019 at 04:23:02PM +1100, Daniel Axtens wrote: > Eric Biggers <ebiggers@xxxxxxxxxx> writes: > > > Hi Daniel, > > > > On Fri, Mar 15, 2019 at 03:24:35PM +1100, Daniel Axtens wrote: > >> Hi Eric, > >> > >> >> The original assembly imported from OpenSSL has two copy-paste > >> >> errors in handling CTR mode. When dealing with a 2 or 3 block tail, > >> >> the code branches to the CBC decryption exit path, rather than to > >> >> the CTR exit path. > >> > > >> > So does this need to be fixed in OpenSSL too? > >> > >> Yes, I'm getting in touch with some people internally (at IBM) about > >> doing that. > >> > >> >> This leads to corruption of the IV, which leads to subsequent blocks > >> >> being corrupted. > >> >> > >> >> This can be detected with libkcapi test suite, which is available at > >> >> https://github.com/smuellerDD/libkcapi > >> >> > >> > > >> > Is this also detected by the kernel's crypto self-tests, and if not why not? > >> > What about with the new option CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y? > >> > >> It seems the self-tests do not catch it. To catch it, there has to be a > >> test where the blkcipher_walk creates a walk.nbytes such that > >> [(the number of AES blocks) mod 8] is either 2 or 3. This happens with > >> AF_ALG pretty frequently, but when I booted with self-tests it only hit > >> 1, 4, 5, 6 and 7 - it missed 0, 2 and 3. > >> > >> I don't have the EXTRA_TESTS option - I'm testing with 5.0-rc6. Is it in > >> -next? > >> > >> Regards, > >> Daniel > > > > The improvements I recently made to the self-tests are intended to catch exactly > > this sort of bug. They were just merged for v5.1, so try the latest mainline. > > This almost certainly would be caught by EXTRA_TESTS (and if not I'd want to > > know), but it may be caught by the regular self-tests now too. > > Well, even the patched code fails with the new self-tests, so clearly > they're catching something! I'll investigate in more detail next week. > > Regards, > Daniel > > > > > - Eric Are you still planning to fix the remaining bug? I booted a ppc64le VM, and I see the same test failure (I think) you were referring to: alg: skcipher: p8_aes_ctr encryption test failed (wrong result) on test vector 3, cfg="uneven misaligned splits, may sleep" - Eric
