diff options
| author | Pauli <paul.dale@oracle.com> | 2018-10-26 10:54:58 +1000 |
|---|---|---|
| committer | Pauli <paul.dale@oracle.com> | 2018-10-29 08:05:06 +1000 |
| commit | 56fb454d281a023b3f950d969693553d3f3ceea1 (patch) | |
| tree | a9f25f5566990c1bd92bba813d5ac8d576ace41c /crypto | |
| parent | ef11e19d1365eea2b1851e6f540a0bf365d303e7 (diff) | |
Timing vulnerability in ECDSA signature generation (CVE-2018-0735)
Preallocate an extra limb for some of the big numbers to avoid a reallocation
that can potentially provide a side channel.
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/7486)
(cherry picked from commit 99540ec79491f59ed8b46b4edf130e17dc907f52)
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/ec/ec_mult.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c index 22bb30ffa1..ff882cce20 100644 --- a/crypto/ec/ec_mult.c +++ b/crypto/ec/ec_mult.c @@ -177,8 +177,8 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r, */ cardinality_bits = BN_num_bits(cardinality); group_top = bn_get_top(cardinality); - if ((bn_wexpand(k, group_top + 1) == NULL) - || (bn_wexpand(lambda, group_top + 1) == NULL)) + if ((bn_wexpand(k, group_top + 2) == NULL) + || (bn_wexpand(lambda, group_top + 2) == NULL)) { goto err; if (!BN_copy(k, scalar)) @@ -205,7 +205,7 @@ static int ec_mul_consttime(const EC_GROUP *group, EC_POINT *r, * k := scalar + 2*cardinality */ kbit = BN_is_bit_set(lambda, cardinality_bits); - BN_consttime_swap(kbit, k, lambda, group_top + 1); + BN_consttime_swap(kbit, k, lambda, group_top + 2); group_top = bn_get_top(group->field); if ((bn_wexpand(s->X, group_top) == NULL) |