soter_rsa_key.h

/*
 * Copyright (c) 2015 Cossack Labs Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef SOTER_RSA_KEY_H
#define SOTER_RSA_KEY_H

#include <soter/soter_container.h>
#include <soter/soter_error.h>

#define RSA_PRIV_KEY_PREF "RRA"
#define RSA_PUB_KEY_PREF "URA"

#define RSA_1024 "1"
#define RSA_2048 "2"
#define RSA_4096 "4"
#define RSA_8192 "8"

#define RSA_SIZE_TAG_1024 '1'
#define RSA_SIZE_TAG_2048 '2'
#define RSA_SIZE_TAG_4096 '4'
#define RSA_SIZE_TAG_8192 '8'

#define RSA_KEY_LENGTH_1024 1
#define RSA_KEY_LENGTH_2048 2
#define RSA_KEY_LENGTH_4096 3
#define RSA_KEY_LENGTH_8192 4

#define RSA_KEY_SUF(_KEY_SIZE_) RSA_##_KEY_SIZE_

#define RSA_PRIV_KEY_TAG(_KEY_SIZE_) (RSA_PRIV_KEY_PREF RSA_KEY_SUF(_KEY_SIZE_))
#define RSA_PUB_KEY_TAG(_KEY_SIZE_) (RSA_PUB_KEY_PREF RSA_KEY_SUF(_KEY_SIZE_))

#define RSA_BYTE_SIZE(_KEY_SIZE_) ((_KEY_SIZE_) / 8)

#define DECLARE_RSA_PUBLIC_KEY(_KEY_SIZE_)         \
    struct soter_rsa_pub_key_##_KEY_SIZE_##_type { \
        soter_container_hdr_t hdr;                 \
        uint8_t mod[RSA_BYTE_SIZE(_KEY_SIZE_)];    \
        uint32_t pub_exp; /* Network byte order */ \
    };                                             \
                                                   \
    typedef struct soter_rsa_pub_key_##_KEY_SIZE_##_type soter_rsa_pub_key_##_KEY_SIZE_##_t

/* Our RSA private key containers include CRT params, since most crypto libraries support them. If
 * at some point CRT params are not available, respective fields a filled with zeroes. */
/* struct members are ordered this way to avoid struct member alignment on different platforms */
#define DECLARE_RSA_PRIVATE_KEY(_KEY_SIZE_)          \
    struct soter_rsa_priv_key_##_KEY_SIZE_##_type {  \
        soter_container_hdr_t hdr;                   \
        uint8_t priv_exp[RSA_BYTE_SIZE(_KEY_SIZE_)]; \
        uint8_t p[RSA_BYTE_SIZE(_KEY_SIZE_) / 2];    \
        uint8_t q[RSA_BYTE_SIZE(_KEY_SIZE_) / 2];    \
        uint8_t dp[RSA_BYTE_SIZE(_KEY_SIZE_) / 2];   \
        uint8_t dq[RSA_BYTE_SIZE(_KEY_SIZE_) / 2];   \
        uint8_t qp[RSA_BYTE_SIZE(_KEY_SIZE_) / 2];   \
        uint8_t mod[RSA_BYTE_SIZE(_KEY_SIZE_)];      \
        uint32_t pub_exp; /* Network byte order */   \
    };                                               \
                                                     \
    typedef struct soter_rsa_priv_key_##_KEY_SIZE_##_type soter_rsa_priv_key_##_KEY_SIZE_##_t

#define DECLARE_RSA_KEY(_KEY_SIZE_)     \
    DECLARE_RSA_PUBLIC_KEY(_KEY_SIZE_); \
    DECLARE_RSA_PRIVATE_KEY(_KEY_SIZE_)
/* We support 1024, 2048, 4096, 8192 RSA keys */
DECLARE_RSA_KEY(1024);
DECLARE_RSA_KEY(2048);
DECLARE_RSA_KEY(4096);
DECLARE_RSA_KEY(8192);

/* Used internally when allocating large enough memory to store key components */
#define RSA_KEY_BYTES_MAX RSA_BYTE_SIZE(8192)

/* This is considered internal API */
typedef void soter_engine_specific_rsa_key_t;

soter_status_t soter_rsa_pub_key_to_engine_specific(const soter_container_hdr_t* key,
                                                    size_t key_length,
                                                    soter_engine_specific_rsa_key_t** engine_key);
soter_status_t soter_rsa_priv_key_to_engine_specific(const soter_container_hdr_t* key,
                                                     size_t key_length,
                                                     soter_engine_specific_rsa_key_t** engine_key);
soter_status_t soter_engine_specific_to_rsa_priv_key(const soter_engine_specific_rsa_key_t* engine_key,
                                                     soter_container_hdr_t* key,
                                                     size_t* key_length);
soter_status_t soter_engine_specific_to_rsa_pub_key(const soter_engine_specific_rsa_key_t* engine_key,
                                                    soter_container_hdr_t* key,
                                                    size_t* key_length);

soter_status_t soter_rsa_pub_key_check_length(const soter_container_hdr_t* key, size_t key_length);
soter_status_t soter_rsa_priv_key_check_length(const soter_container_hdr_t* key, size_t key_length);

#endif /* SOTER_RSA_KEY_H */