diff options
| -rw-r--r-- | ecdsa.c | 43 |
1 files changed, 35 insertions, 8 deletions
@@ -978,11 +978,9 @@ hal_error_t hal_ecdsa_key_load_public(hal_ecdsa_key_t **key_, } /* - * Load a private key from components; does all the same things as - * hal_ecdsa_key_load_public(), then loads the private key itself and - * adjusts the key type. - * - * For extra paranoia, we could check Q == dG. + * Load a private key from components: does the same things as + * hal_ecdsa_key_load_public(), but also checks the private key, and + * generates the public key from the private key if necessary. */ hal_error_t hal_ecdsa_key_load_private(hal_ecdsa_key_t **key_, @@ -992,18 +990,47 @@ hal_error_t hal_ecdsa_key_load_private(hal_ecdsa_key_t **key_, const uint8_t * const y, const size_t y_len, const uint8_t * const d, const size_t d_len) { + const ecdsa_curve_t * const curve = get_curve(curve_); hal_ecdsa_key_t *key = keybuf; hal_error_t err; - if (d == NULL) + if (key_ == NULL || key == NULL || keybuf_len < sizeof(*key) || curve == NULL || + d == NULL || d_len == 0 || (x == NULL && x_len != 0) || (y == NULL && y_len != 0)) return HAL_ERROR_BAD_ARGUMENTS; - if ((err = hal_ecdsa_key_load_public(key_, keybuf, keybuf_len, curve_, x, x_len, y, y_len)) != HAL_OK) - return err; + memset(keybuf, 0, keybuf_len); key->type = HAL_KEY_TYPE_EC_PRIVATE; + key->curve = curve_; + fp_read_unsigned_bin(key->d, unconst_uint8_t(d), d_len); + + if (fp_iszero(key->d) || fp_cmp(key->d, unconst_fp_int(curve->n)) != FP_LT) + lose(HAL_ERROR_BAD_ARGUMENTS); + + fp_set(key->Q->z, 1); + + if (x_len != 0 || y_len != 0) { + fp_read_unsigned_bin(key->Q->x, unconst_uint8_t(x), x_len); + fp_read_unsigned_bin(key->Q->y, unconst_uint8_t(y), y_len); + } + + else { + fp_copy(curve->Gx, key->Q->x); + fp_copy(curve->Gy, key->Q->y); + if ((err = point_scalar_multiply(key->d, key->Q, key->Q, curve)) != HAL_OK) + goto fail; + } + + if (!point_is_on_curve(key->Q, curve)) + lose(HAL_ERROR_KEY_NOT_ON_CURVE); + + *key_ = key; return HAL_OK; + + fail: + memset(keybuf, 0, keybuf_len); + return err; } /* |