1. 28 Feb, 2019 2 commits
  2. 27 Feb, 2019 5 commits
  3. 26 Feb, 2019 12 commits
  4. 25 Feb, 2019 2 commits
    • Richard Levitte's avatar
      Rearrange the inclusion of curve448/curve448_lcl.h · f408e2a3
      Richard Levitte authored
      
      
      The real cause for this change is that test/ec_internal_test.c
      includes ec_lcl.h, and including curve448/curve448_lcl.h from there
      doesn't work so well with compilers who always do inclusions relative
      to the C file being compiled.
      
      Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
      (Merged from https://github.com/openssl/openssl/pull/8334)
      f408e2a3
    • Matt Caswell's avatar
      Ensure bn_cmp_words can handle the case where n == 0 · df2cb82a
      Matt Caswell authored
      
      
      Thanks to David Benjamin who reported this, performed the analysis and
      suggested the patch. I have incorporated some of his analysis in the
      comments below.
      
      This issue can cause an out-of-bounds read. It is believed that this was
      not reachable until the recent "fixed top" changes. Analysis has so far
      only identified one code path that can encounter this - although it is
      possible that others may be found. The one code path only impacts 1.0.2 in
      certain builds. The fuzzer found a path in RSA where iqmp is too large. If
      the input is all zeros, the RSA CRT logic will multiply a padded zero by
      iqmp. Two mitigating factors:
      
      - Private keys which trip this are invalid (iqmp is not reduced mod p).
      Only systems which take untrusted private keys care.
      - In OpenSSL 1.1.x, there is a check which rejects the oversize iqmp,
      so the bug is only reproducible in 1.0.2 so far.
      
      Fortunately, the bug appears to be relatively harmless. The consequences of
      bn_cmp_word's misbehavior are:
      
      - OpenSSL may crash if the buffers are page-aligned and the previous page is
      non-existent.
      - OpenSSL will incorrectly treat two BN_ULONG buffers as not equal when they
      are equal.
      - Side channel concerns.
      
      The first is indeed a concern and is a DoS bug. The second is fine in this
      context. bn_cmp_word and bn_cmp_part_words are used to compute abs(a0 - a1)
      in Karatsuba. If a0 = a1, it does not matter whether we use a0 - a1 or
      a1 - a0. The third would be worth thinking about, but it is overshadowed
      by the entire Karatsuba implementation not being constant time.
      
      Due to the difficulty of tripping this and the low impact no CVE is felt
      necessary for this issue.
      
      Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
      Reviewed-by: default avatarViktor Dukhovni <viktor@openssl.org>
      (Merged from https://github.com/openssl/openssl/pull/8326)
      
      (cherry picked from commit 576129cd72ae054d246221f111aabf42b9c6d76d)
      df2cb82a
  5. 22 Feb, 2019 4 commits
  6. 21 Feb, 2019 2 commits
  7. 20 Feb, 2019 4 commits
    • Nicola Tuveri's avatar
      Clear BN_FLG_CONSTTIME on BN_CTX_get() · e2e69dce
      Nicola Tuveri authored
      (cherry picked from commit c8147d37
      
      )
      
      Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
      (Merged from https://github.com/openssl/openssl/pull/8253)
      e2e69dce
    • Nicola Tuveri's avatar
      Test for constant-time flag leakage in BN_CTX · 3c97136e
      Nicola Tuveri authored
      This commit adds a simple unit test to make sure that the constant-time
      flag does not "leak" among BN_CTX frames:
      
      - test_ctx_consttime_flag() initializes (and later frees before
        returning) a BN_CTX object, then it calls in sequence
        test_ctx_set_ct_flag() and test_ctx_check_ct_flag() using the same
        BN_CTX object. The process is run twice, once with a "normal"
        BN_CTX_new() object, then with a BN_CTX_secure_new() one.
      - test_ctx_set_ct_flag() starts a frame in the given BN_CTX and sets the
        BN_FLG_CONSTTIME flag on some of the BIGNUMs obtained from the frame
        before ending it.
      - test_ctx_check_ct_flag() then starts a new frame and gets a number of
        BIGNUMs from it. In absence of leaks, none of the BIGNUMs in the new
        frame should have BN_FLG_CONSTTIME set.
      
      In actual BN_CTX usage inside libcrypto the leak could happen at any
      depth level in the BN_CTX stack, with varying results depending on the
      patterns of sibling trees of nested function calls sharing the same
      BN_CTX object, and the effect of unintended BN_FLG_CONSTTIME on the
      called BN_* functions.
      
      This simple unit test abstracts away this complexity and verifies that
      the leak does not happen between two sibling functions sharing the same
      BN_CTX object at the same level of nesting.
      
      (cherry picked from commit fe16ae5f
      
      )
      
      Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
      (Merged from https://github.com/openssl/openssl/pull/8253)
      3c97136e
    • Billy Brumley's avatar
      d11e4bcd
    • Billy Brumley's avatar
      SCA hardening for mod. field inversion in EC_GROUP · 48e82c8e
      Billy Brumley authored
      
      
      This commit adds a dedicated function in `EC_METHOD` to access a modular
      field inversion implementation suitable for the specifics of the
      implemented curve, featuring SCA countermeasures.
      
      The new pointer is defined as:
      `int (*field_inv)(const EC_GROUP*, BIGNUM *r, const BIGNUM *a, BN_CTX*)`
      and computes the multiplicative inverse of `a` in the underlying field,
      storing the result in `r`.
      
      Three implementations are included, each including specific SCA
      countermeasures:
        - `ec_GFp_simple_field_inv()`, featuring SCA hardening through
          blinding.
        - `ec_GFp_mont_field_inv()`, featuring SCA hardening through Fermat's
          Little Theorem (FLT) inversion.
        - `ec_GF2m_simple_field_inv()`, that uses `BN_GF2m_mod_inv()` which
          already features SCA hardening through blinding.
      
      From a security point of view, this also helps addressing a leakage
      previously affecting conversions from projective to affine coordinates.
      
      This commit also adds a new error reason code (i.e.,
      `EC_R_CANNOT_INVERT`) to improve consistency between the three
      implementations as all of them could fail for the same reason but
      through different code paths resulting in inconsistent error stack
      states.
      
      Co-authored-by: default avatarNicola Tuveri <nic.tuv@gmail.com>
      
      (cherry picked from commit e0033efc30b0f00476bba8f0fa5512be5dc8a3f1)
      
      Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
      Reviewed-by: default avatarNicola Tuveri <nic.tuv@gmail.com>
      (Merged from https://github.com/openssl/openssl/pull/8262)
      48e82c8e
  8. 19 Feb, 2019 4 commits
  9. 18 Feb, 2019 1 commit
  10. 17 Feb, 2019 4 commits