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  1. 30 Jun, 2019 1 commit
  3. 09 Jun, 2019 1 commit
  5. 28 May, 2019 2 commits
  7. 27 May, 2019 2 commits
  9. 21 May, 2019 1 commit
  11. 26 Feb, 2019 2 commits
  13. 20 Feb, 2019 1 commit
    • 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
  15. 14 Feb, 2019 1 commit
    • Matt Caswell's avatar
      Don't signal SSL_CB_HANDSHAKE_START for TLSv1.3 post-handshake messages · 37857e9b
      Matt Caswell authored 
      

The original 1.1.1 design was to use SSL_CB_HANDSHAKE_START and
SSL_CB_HANDSHAKE_DONE to signal start/end of a post-handshake message
exchange in TLSv1.3. Unfortunately experience has shown that this confuses
some applications who mistake it for a TLSv1.2 renegotiation. This means
that KeyUpdate messages are not handled properly.

This commit removes the use of SSL_CB_HANDSHAKE_START and
SSL_CB_HANDSHAKE_DONE to signal the start/end of a post-handshake
message exchange. Individual post-handshake messages are still signalled in
the normal way.

This is a potentially breaking change if there are any applications already
written that expect to see these TLSv1.3 events. However, without it,
KeyUpdate is not currently usable for many applications.

Fixes #8069

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8096)

(cherry picked from commit 4af5836b)
      37857e9b
  17. 02 Feb, 2019 1 commit
  19. 01 Feb, 2019 1 commit
  21. 07 Dec, 2018 1 commit
  23. 24 Nov, 2018 1 commit
  25. 20 Nov, 2018 3 commits
  27. 17 Oct, 2018 1 commit
  29. 16 Oct, 2018 1 commit
    • Dr. Matthias St. Pierre's avatar
      DRBG: fix reseeding via RAND_add()/RAND_seed() with large input · dbf0a496
      Dr. Matthias St. Pierre authored 
      In pull request #4328 the seeding of the DRBG via RAND_add()/RAND_seed()
was implemented by buffering the data in a random pool where it is
picked up later by the rand_drbg_get_entropy() callback. This buffer
was limited to the size of 4096 bytes.

When a larger input was added via RAND_add() or RAND_seed() to the DRBG,
the reseeding failed, but the error returned by the DRBG was ignored
by the two calling functions, which both don't return an error code.
As a consequence, the data provided by the application was effectively
ignored.

This commit fixes the problem by a more efficient implementation which
does not copy the data in memory and by raising the buffer the size limit
to INT32_MAX (2 gigabytes). This is less than the NIST limit of 2^35 bits
but it was chosen intentionally to avoid platform dependent problems
like integer sizes and/or signed/unsigned conversion.

Additionally, the DRBG is now less permissive on errors: In addition to
...
      dbf0a496
  31. 11 Sep, 2018 2 commits
  33. 10 Sep, 2018 2 commits
  35. 21 Aug, 2018 1 commit
  37. 15 Aug, 2018 1 commit
  39. 14 Aug, 2018 1 commit
  41. 07 Aug, 2018 2 commits
  43. 26 Jul, 2018 3 commits
  45. 23 Jul, 2018 1 commit
  47. 18 Jul, 2018 1 commit
  49. 16 Jul, 2018 2 commits
    • Nicola Tuveri's avatar
      EC2M Lopez-Dahab ladder implementation · f45846f5
      Nicola Tuveri authored 
      This commit uses the new ladder scaffold to implement a specialized
ladder step based on differential addition-and-doubling in mixed
Lopez-Dahab projective coordinates, modified to independently blind the
operands.

The arithmetic in `ladder_pre`, `ladder_step` and `ladder_post` is
auto generated with tooling:
- see, e.g., "Guide to ECC" Alg 3.40 for reference about the
  `ladder_pre` implementation;
- see https://www.hyperelliptic.org/EFD/g12o/auto-code/shortw/xz/ladder/mladd-2003-s.op3


  for the differential addition-and-doubling formulas implemented in
  `ladder_step`;
- see, e.g., "Fast Multiplication on Elliptic Curves over GF(2**m)
  without Precomputation" (Lopez and Dahab, CHES 1999) Appendix Alg Mxy
  for the `ladder_post` implementation to recover the `(x,y)` result in
  affine coordinates.

Co-authored-by: default avatarBilly Brumley <bbrumley@gmail.com>
Co-authored-by: default avatarSohaib ul Hassan <soh.19.hassan@gmail.com>

Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6690)
      f45846f5
    • Nicola Tuveri's avatar
      EC point multiplication: add `ladder` scaffold · 37124360
      Nicola Tuveri authored 
      
for specialized Montgomery ladder implementations

PR #6009 and #6070 replaced the default EC point multiplication path for
prime and binary curves with a unified Montgomery ladder implementation
with various timing attack defenses (for the common paths when a secret
scalar is feed to the point multiplication).
The newly introduced default implementation directly used
EC_POINT_add/dbl in the main loop.

The scaffolding introduced by this commit allows EC_METHODs to define a
specialized `ladder_step` function to improve performances by taking
advantage of efficient formulas for differential addition-and-doubling
and different coordinate systems.

- `ladder_pre` is executed before the main loop of the ladder: by
  default it copies the input point P into S, and doubles it into R.
  Specialized implementations could, e.g., use this hook to transition
  to different coordinate systems before copying and doubling;
- `ladder_step` is the core of the Montgomery ladder loop: by default it
  computes `S := R+S; R := 2R;`, but specific implementations could,
  e.g., implement a more efficient formula for differential
  addition-and-doubling;
- `ladder_post` is executed after the Montgomery ladder loop: by default
  it's a noop, but specialized implementations could, e.g., use this
  hook to transition back from the coordinate system used for optimizing
  the differential addition-and-doubling or recover the y coordinate of
  the result point.

This commit also renames `ec_mul_consttime` to `ec_scalar_mul_ladder`,
as it better corresponds to what this function does: nothing can be
truly said about the constant-timeness of the overall execution of this
function, given that the underlying operations are not necessarily
constant-time themselves.
What this implementation ensures is that the same fixed sequence of
operations is executed for each scalar multiplication (for a given
EC_GROUP), with no dependency on the value of the input scalar.

Co-authored-by: default avatarSohaib ul Hassan <soh.19.hassan@gmail.com>
Co-authored-by: default avatarBilly Brumley <bbrumley@gmail.com>

Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6690)
      37124360
  51. 08 Jul, 2018 1 commit
  53. 26 Jun, 2018 1 commit
  55. 22 Jun, 2018 2 commits