openbsd/src/lib/libcrypto/ec/ec2_smpl.c, branch OPENBSD_6_8_BASE

Implement coordinate blinding for EC_POINT.

2018-11-05T20:18:21+00:00

Based on OpenSSL commit 875ba8b21ecc65ad9a6bdc66971e50 by Billy Brumley, Sohaib ul Hassan and Nicola Tuveri. ok beck jsing commit 875ba8b21ecc65ad9a6bdc66971e50461660fcbb Author: Sohaib ul Hassan Date: Sat Jun 16 17:07:40 2018 +0300 Implement coordinate blinding for EC_POINT This commit implements coordinate blinding, i.e., it randomizes the representative of an elliptic curve point in its equivalence class, for prime curves implemented through EC_GFp_simple_method, EC_GFp_mont_method, and EC_GFp_nist_method. This commit is derived from the patch https://marc.info/?l=openssl-dev&m=131194808413635 by Billy Brumley. Coordinate blinding is a generally useful side-channel countermeasure and is (mostly) free. The function itself takes a few field multiplicationss, but is usually only necessary at the beginning of a scalar multiplication (as implemented in the patch). When used this way, it makes the values that variables take (i.e., field elements in an algorithm state) unpredictable. For instance, this mitigates chosen EC point side-channel attacks for settings such as ECDH and EC private key decryption, for the aforementioned curves. For EC_METHODs using different coordinate representations this commit does nothing, but the corresponding coordinate blinding function can be easily added in the future to extend these changes to such curves. Co-authored-by: Nicola Tuveri Co-authored-by: Billy Brumley Reviewed-by: Tim Hudson Reviewed-by: Nicola Tuveri Reviewed-by: Andy Polyakov (Merged from https://github.com/openssl/openssl/pull/6526)

Recommit Billy Brumley's ECC constant time patch with a fix for sparc64

2018-07-16T17:32:39+00:00

from Nicola Tuveri (who spotted the omission of ecp_nist.c from the PR). discussed with jsing tested by jsg

recommit label indentation part of the backout; clearly unrelated to the

2018-07-15T16:27:39+00:00

breakage.

back out ecc constant time changes

2018-07-15T05:38:48+00:00

after the constant time commits various regress tests started failing on sparc64 ssh t9, libcrypto ec ecdh ecdsa and trying to ssh out resulted in 'invalid elliptic curve value' ok tb@

Indent labels by a space so they don't obliterate function names in diffs.

2018-07-10T22:06:14+00:00

ECC constant time scalar multiplication support. First step in overhauling

2018-07-10T21:55:49+00:00

the EC module. From Billy Brumley and his team, via https://github.com/libressl-portable/openbsd/pull/94 With tweaks from jsing and me. ok jsing

Send the function codes from the error functions to the bit bucket,

2017-01-29T17:49:23+00:00

as was done earlier in libssl. Thanks inoguchi@ for noticing libssl had more reacharounds into this. ok jsing@ inoguchi@

BN_CTX_get() can fail - consistently check its return value.

2015-02-09T15:49:22+00:00

There are currently cases where the return from each call is checked, the return from only the last call is checked and cases where it is not checked at all (including code in bn, ec and engine). Checking the last return value is valid as once the function fails it will continue to return NULL. However, in order to be consistent check each call with the same idiom. This makes it easy to verify. Note there are still a handful of cases that do not follow the idiom - these will be handled separately. ok beck@ doug@

Use `> 0' instead of `!= 0' as a successful condition for

2015-02-08T22:25:03+00:00

EC_POINT_is_at_infinity() and EC_POINT_is_on_curve(), for they may return -1 should an error arise. ok doug@ jsing@

if (x) FOO_free(x) -> FOO_free(x).

2014-07-12T16:03:37+00:00

Improves readability, keeps the code smaller so that it is warmer in your cache. review & ok deraadt@