[tor-bugs] #16189 [Tor]: Ensure our scrypt interoperates with openssl's scrypt

[Tor Bug Tracker & Wiki]

#16189: Ensure our scrypt interoperates with openssl's scrypt
------------------------+--------------------------------
     Reporter:  nickm   |      Owner:  rl1987
         Type:  defect  |     Status:  needs_revision
     Priority:  normal  |  Milestone:  Tor: 0.2.7.x-final
    Component:  Tor     |    Version:
   Resolution:          |   Keywords:
Actual Points:          |  Parent ID:
       Points:          |
------------------------+--------------------------------

Comment (by rl1987):

 Replying to [comment:5 nickm]:

 > > I have preliminary patch for this:
 ​https://github.com/rl1987/tor/compare/libscrypt_eq_openssl
 > >
 > >
 >
 > Looks promising. We'll need to pull it out eventually, once we add some
 logic to stop linking libscrypt when openssl has scrypt... but for now it
 should be fine.
 >
 > There's a logic bug, though: The code that calls EVP_PBE_scrypt() needs
 to be disabled entirely when openssl doesn't have that function, or our
 tests won't compile.
 >

 I pushed one more commit that fixes this.

 > > OpenSSL seems to fail with the last test vector from draft-josefsson-
 scrypt-kdf-00 section 11.
 > >
 > >
 >
 > Hmmm.  Does libscrypt pass with that test vector?  If so, we should
 submit a bug to the openssl people so they don't release a broken scrypt
 implementation.
 >

 It seems to, since libscrypt is being tested independently in
 `test_crypto_scrypt_vectors()` and this test does not fail. I have
 isolated the failing part using `#if 0` so that others could take a look.
 If you enable that part of the code, you will see that `EVP_PBE_scrypt()`
 returns the failure status if you try to compute key with the last test
 vector in Section 11.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16189#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online