mirror/openssl
2
0
Fork 0
mirror of https://github.com/openssl/openssl.git synced 2025-04-12 20:30:52 +08:00
Code Issues Packages Projects Releases Wiki Activity

Don't use coordinate blinding when scalar is group order

Browse Source 
This happens in ec_key_simple_check_key and EC_GROUP_check.
Since the the group order is not a secret scalar, it is
unnecessary to use coordinate blinding.

Fixes: #8731

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8734)
This commit is contained in:
Bernd Edlinger 2019-04-12 14:28:00 +02:00
parent 938e82f622
commit 3051bf2afa
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
crypto/ec/ec_mult.c
View File

@ -441,7 +441,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
* scalar multiplication implementation based on a Montgomery ladder,
* with various timing attack defenses.
*/
if ((scalar != NULL) && (num == 0)) {
if ((scalar != group->order) && (scalar != NULL) && (num == 0)) {
/*-
* In this case we want to compute scalar * GeneratorPoint: this
* codepath is reached most prominently by (ephemeral) key
@ -452,7 +452,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
*/
return ec_scalar_mul_ladder(group, r, scalar, NULL, ctx);
}
if ((scalar == NULL) && (num == 1)) {
if ((scalar == NULL) && (num == 1) && (scalars[0] != group->order)) {
/*-
* In this case we want to compute scalar * VariablePoint: this
* codepath is reached most prominently by the second half of ECDH,