|  | /* | 
|  | *  Public Key layer for writing key files and structures | 
|  | * | 
|  | *  Copyright The Mbed TLS Contributors | 
|  | *  SPDX-License-Identifier: Apache-2.0 | 
|  | * | 
|  | *  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. | 
|  | */ | 
|  |  | 
|  | #include "common.h" | 
|  |  | 
|  | #if defined(MBEDTLS_PK_WRITE_C) | 
|  |  | 
|  | #include "mbedtls/pk.h" | 
|  | #include "mbedtls/asn1write.h" | 
|  | #include "mbedtls/oid.h" | 
|  | #include "mbedtls/platform_util.h" | 
|  | #include "mbedtls/error.h" | 
|  |  | 
|  | #include <string.h> | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | #include "mbedtls/rsa.h" | 
|  | #endif | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | #include "mbedtls/bignum.h" | 
|  | #include "mbedtls/ecp.h" | 
|  | #include "mbedtls/platform_util.h" | 
|  | #endif | 
|  | #if defined(MBEDTLS_ECDSA_C) | 
|  | #include "mbedtls/ecdsa.h" | 
|  | #endif | 
|  | #if defined(MBEDTLS_PEM_WRITE_C) | 
|  | #include "mbedtls/pem.h" | 
|  | #endif | 
|  |  | 
|  | #if defined(MBEDTLS_USE_PSA_CRYPTO) | 
|  | #include "psa/crypto.h" | 
|  | #include "mbedtls/psa_util.h" | 
|  | #endif | 
|  | #include "mbedtls/platform.h" | 
|  |  | 
|  | /* Parameter validation macros based on platform_util.h */ | 
|  | #define PK_VALIDATE_RET(cond)    \ | 
|  | MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA) | 
|  | #define PK_VALIDATE(cond)        \ | 
|  | MBEDTLS_INTERNAL_VALIDATE(cond) | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | /* | 
|  | *  RSAPublicKey ::= SEQUENCE { | 
|  | *      modulus           INTEGER,  -- n | 
|  | *      publicExponent    INTEGER   -- e | 
|  | *  } | 
|  | */ | 
|  | static int pk_write_rsa_pubkey(unsigned char **p, unsigned char *start, | 
|  | mbedtls_rsa_context *rsa) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | size_t len = 0; | 
|  | mbedtls_mpi T; | 
|  |  | 
|  | mbedtls_mpi_init(&T); | 
|  |  | 
|  | /* Export E */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export N */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | end_of_export: | 
|  |  | 
|  | mbedtls_mpi_free(&T); | 
|  | if (ret < 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED | | 
|  | MBEDTLS_ASN1_SEQUENCE)); | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  | #endif /* MBEDTLS_RSA_C */ | 
|  |  | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | /* | 
|  | * EC public key is an EC point | 
|  | */ | 
|  | static int pk_write_ec_pubkey(unsigned char **p, unsigned char *start, | 
|  | mbedtls_ecp_keypair *ec) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | size_t len = 0; | 
|  | unsigned char buf[MBEDTLS_ECP_MAX_PT_LEN]; | 
|  |  | 
|  | if ((ret = mbedtls_ecp_point_write_binary(&ec->grp, &ec->Q, | 
|  | MBEDTLS_ECP_PF_UNCOMPRESSED, | 
|  | &len, buf, sizeof(buf))) != 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | if (*p < start || (size_t) (*p - start) < len) { | 
|  | return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; | 
|  | } | 
|  |  | 
|  | *p -= len; | 
|  | memcpy(*p, buf, len); | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * ECParameters ::= CHOICE { | 
|  | *   namedCurve         OBJECT IDENTIFIER | 
|  | * } | 
|  | */ | 
|  | static int pk_write_ec_param(unsigned char **p, unsigned char *start, | 
|  | mbedtls_ecp_keypair *ec) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | size_t len = 0; | 
|  | const char *oid; | 
|  | size_t oid_len; | 
|  |  | 
|  | if ((ret = mbedtls_oid_get_oid_by_ec_grp(ec->grp.id, &oid, &oid_len)) != 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid, oid_len)); | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * privateKey  OCTET STRING -- always of length ceil(log2(n)/8) | 
|  | */ | 
|  | static int pk_write_ec_private(unsigned char **p, unsigned char *start, | 
|  | mbedtls_ecp_keypair *ec) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | size_t byte_length = (ec->grp.pbits + 7) / 8; | 
|  | unsigned char tmp[MBEDTLS_ECP_MAX_BYTES]; | 
|  |  | 
|  | ret = mbedtls_ecp_write_key(ec, tmp, byte_length); | 
|  | if (ret != 0) { | 
|  | goto exit; | 
|  | } | 
|  | ret = mbedtls_asn1_write_octet_string(p, start, tmp, byte_length); | 
|  |  | 
|  | exit: | 
|  | mbedtls_platform_zeroize(tmp, byte_length); | 
|  | return ret; | 
|  | } | 
|  | #endif /* MBEDTLS_ECP_C */ | 
|  |  | 
|  | int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start, | 
|  | const mbedtls_pk_context *key) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | size_t len = 0; | 
|  |  | 
|  | PK_VALIDATE_RET(p != NULL); | 
|  | PK_VALIDATE_RET(*p != NULL); | 
|  | PK_VALIDATE_RET(start != NULL); | 
|  | PK_VALIDATE_RET(key != NULL); | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) { | 
|  | MBEDTLS_ASN1_CHK_ADD(len, pk_write_rsa_pubkey(p, start, mbedtls_pk_rsa(*key))); | 
|  | } else | 
|  | #endif | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) { | 
|  | MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_pubkey(p, start, mbedtls_pk_ec(*key))); | 
|  | } else | 
|  | #endif | 
|  | #if defined(MBEDTLS_USE_PSA_CRYPTO) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_OPAQUE) { | 
|  | size_t buffer_size; | 
|  | psa_key_id_t *key_id = (psa_key_id_t *) key->pk_ctx; | 
|  |  | 
|  | if (*p < start) { | 
|  | return MBEDTLS_ERR_PK_BAD_INPUT_DATA; | 
|  | } | 
|  |  | 
|  | buffer_size = (size_t) (*p - start); | 
|  | if (psa_export_public_key(*key_id, start, buffer_size, &len) | 
|  | != PSA_SUCCESS) { | 
|  | return MBEDTLS_ERR_PK_BAD_INPUT_DATA; | 
|  | } else { | 
|  | *p -= len; | 
|  | memmove(*p, start, len); | 
|  | } | 
|  | } else | 
|  | #endif /* MBEDTLS_USE_PSA_CRYPTO */ | 
|  | return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE; | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  |  | 
|  | int mbedtls_pk_write_pubkey_der(mbedtls_pk_context *key, unsigned char *buf, size_t size) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | unsigned char *c; | 
|  | size_t len = 0, par_len = 0, oid_len; | 
|  | mbedtls_pk_type_t pk_type; | 
|  | const char *oid; | 
|  |  | 
|  | PK_VALIDATE_RET(key != NULL); | 
|  | if (size == 0) { | 
|  | return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; | 
|  | } | 
|  | PK_VALIDATE_RET(buf != NULL); | 
|  |  | 
|  | c = buf + size; | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_pk_write_pubkey(&c, buf, key)); | 
|  |  | 
|  | if (c - buf < 1) { | 
|  | return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; | 
|  | } | 
|  |  | 
|  | /* | 
|  | *  SubjectPublicKeyInfo  ::=  SEQUENCE  { | 
|  | *       algorithm            AlgorithmIdentifier, | 
|  | *       subjectPublicKey     BIT STRING } | 
|  | */ | 
|  | *--c = 0; | 
|  | len += 1; | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_BIT_STRING)); | 
|  |  | 
|  | pk_type = mbedtls_pk_get_type(key); | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | if (pk_type == MBEDTLS_PK_ECKEY) { | 
|  | MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, mbedtls_pk_ec(*key))); | 
|  | } | 
|  | #endif | 
|  | #if defined(MBEDTLS_USE_PSA_CRYPTO) | 
|  | if (pk_type == MBEDTLS_PK_OPAQUE) { | 
|  | psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; | 
|  | psa_key_type_t key_type; | 
|  | psa_key_id_t key_id; | 
|  | psa_ecc_family_t curve; | 
|  | size_t bits; | 
|  |  | 
|  | key_id = *((psa_key_id_t *) key->pk_ctx); | 
|  | if (PSA_SUCCESS != psa_get_key_attributes(key_id, &attributes)) { | 
|  | return MBEDTLS_ERR_PK_HW_ACCEL_FAILED; | 
|  | } | 
|  | key_type = psa_get_key_type(&attributes); | 
|  | bits = psa_get_key_bits(&attributes); | 
|  | psa_reset_key_attributes(&attributes); | 
|  |  | 
|  | curve = PSA_KEY_TYPE_ECC_GET_FAMILY(key_type); | 
|  | if (curve == 0) { | 
|  | return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE; | 
|  | } | 
|  |  | 
|  | ret = mbedtls_psa_get_ecc_oid_from_id(curve, bits, &oid, &oid_len); | 
|  | if (ret != 0) { | 
|  | return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE; | 
|  | } | 
|  |  | 
|  | /* Write EC algorithm parameters; that's akin | 
|  | * to pk_write_ec_param() above. */ | 
|  | MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_oid(&c, buf, | 
|  | oid, oid_len)); | 
|  |  | 
|  | /* The rest of the function works as for legacy EC contexts. */ | 
|  | pk_type = MBEDTLS_PK_ECKEY; | 
|  | } | 
|  | #endif /* MBEDTLS_USE_PSA_CRYPTO */ | 
|  |  | 
|  | if ((ret = mbedtls_oid_get_oid_by_pk_alg(pk_type, &oid, | 
|  | &oid_len)) != 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(&c, buf, oid, oid_len, | 
|  | par_len)); | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED | | 
|  | MBEDTLS_ASN1_SEQUENCE)); | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  |  | 
|  | int mbedtls_pk_write_key_der(mbedtls_pk_context *key, unsigned char *buf, size_t size) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | unsigned char *c; | 
|  | size_t len = 0; | 
|  |  | 
|  | PK_VALIDATE_RET(key != NULL); | 
|  | if (size == 0) { | 
|  | return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; | 
|  | } | 
|  | PK_VALIDATE_RET(buf != NULL); | 
|  |  | 
|  | c = buf + size; | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) { | 
|  | mbedtls_mpi T; /* Temporary holding the exported parameters */ | 
|  | mbedtls_rsa_context *rsa = mbedtls_pk_rsa(*key); | 
|  |  | 
|  | /* | 
|  | * Export the parameters one after another to avoid simultaneous copies. | 
|  | */ | 
|  |  | 
|  | mbedtls_mpi_init(&T); | 
|  |  | 
|  | /* Export QP */ | 
|  | if ((ret = mbedtls_rsa_export_crt(rsa, NULL, NULL, &T)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export DQ */ | 
|  | if ((ret = mbedtls_rsa_export_crt(rsa, NULL, &T, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export DP */ | 
|  | if ((ret = mbedtls_rsa_export_crt(rsa, &T, NULL, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export Q */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, | 
|  | &T, NULL, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export P */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, NULL, &T, | 
|  | NULL, NULL, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export D */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, | 
|  | NULL, &T, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export E */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, | 
|  | NULL, NULL, &T)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | /* Export N */ | 
|  | if ((ret = mbedtls_rsa_export(rsa, &T, NULL, | 
|  | NULL, NULL, NULL)) != 0 || | 
|  | (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) { | 
|  | goto end_of_export; | 
|  | } | 
|  | len += ret; | 
|  |  | 
|  | end_of_export: | 
|  |  | 
|  | mbedtls_mpi_free(&T); | 
|  | if (ret < 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf, 0)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, | 
|  | buf, MBEDTLS_ASN1_CONSTRUCTED | | 
|  | MBEDTLS_ASN1_SEQUENCE)); | 
|  | } else | 
|  | #endif /* MBEDTLS_RSA_C */ | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) { | 
|  | mbedtls_ecp_keypair *ec = mbedtls_pk_ec(*key); | 
|  | size_t pub_len = 0, par_len = 0; | 
|  |  | 
|  | /* | 
|  | * RFC 5915, or SEC1 Appendix C.4 | 
|  | * | 
|  | * ECPrivateKey ::= SEQUENCE { | 
|  | *      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1), | 
|  | *      privateKey     OCTET STRING, | 
|  | *      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL, | 
|  | *      publicKey  [1] BIT STRING OPTIONAL | 
|  | *    } | 
|  | */ | 
|  |  | 
|  | /* publicKey */ | 
|  | MBEDTLS_ASN1_CHK_ADD(pub_len, pk_write_ec_pubkey(&c, buf, ec)); | 
|  |  | 
|  | if (c - buf < 1) { | 
|  | return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL; | 
|  | } | 
|  | *--c = 0; | 
|  | pub_len += 1; | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(&c, buf, pub_len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_BIT_STRING)); | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(&c, buf, pub_len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(&c, buf, | 
|  | MBEDTLS_ASN1_CONTEXT_SPECIFIC | | 
|  | MBEDTLS_ASN1_CONSTRUCTED | 1)); | 
|  | len += pub_len; | 
|  |  | 
|  | /* parameters */ | 
|  | MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, ec)); | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_len(&c, buf, par_len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_tag(&c, buf, | 
|  | MBEDTLS_ASN1_CONTEXT_SPECIFIC | | 
|  | MBEDTLS_ASN1_CONSTRUCTED | 0)); | 
|  | len += par_len; | 
|  |  | 
|  | /* privateKey */ | 
|  | MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_private(&c, buf, ec)); | 
|  |  | 
|  | /* version */ | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf, 1)); | 
|  |  | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len)); | 
|  | MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED | | 
|  | MBEDTLS_ASN1_SEQUENCE)); | 
|  | } else | 
|  | #endif /* MBEDTLS_ECP_C */ | 
|  | return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE; | 
|  |  | 
|  | return (int) len; | 
|  | } | 
|  |  | 
|  | #if defined(MBEDTLS_PEM_WRITE_C) | 
|  |  | 
|  | #define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----\n" | 
|  | #define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----\n" | 
|  |  | 
|  | #define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----\n" | 
|  | #define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----\n" | 
|  | #define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n" | 
|  | #define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n" | 
|  |  | 
|  | /* | 
|  | * Max sizes of key per types. Shown as tag + len (+ content). | 
|  | */ | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | /* | 
|  | * RSA public keys: | 
|  | *  SubjectPublicKeyInfo  ::=  SEQUENCE  {          1 + 3 | 
|  | *       algorithm            AlgorithmIdentifier,  1 + 1 (sequence) | 
|  | *                                                + 1 + 1 + 9 (rsa oid) | 
|  | *                                                + 1 + 1 (params null) | 
|  | *       subjectPublicKey     BIT STRING }          1 + 3 + (1 + below) | 
|  | *  RSAPublicKey ::= SEQUENCE {                     1 + 3 | 
|  | *      modulus           INTEGER,  -- n            1 + 3 + MPI_MAX + 1 | 
|  | *      publicExponent    INTEGER   -- e            1 + 3 + MPI_MAX + 1 | 
|  | *  } | 
|  | */ | 
|  | #define RSA_PUB_DER_MAX_BYTES   (38 + 2 * MBEDTLS_MPI_MAX_SIZE) | 
|  |  | 
|  | /* | 
|  | * RSA private keys: | 
|  | *  RSAPrivateKey ::= SEQUENCE {                    1 + 3 | 
|  | *      version           Version,                  1 + 1 + 1 | 
|  | *      modulus           INTEGER,                  1 + 3 + MPI_MAX + 1 | 
|  | *      publicExponent    INTEGER,                  1 + 3 + MPI_MAX + 1 | 
|  | *      privateExponent   INTEGER,                  1 + 3 + MPI_MAX + 1 | 
|  | *      prime1            INTEGER,                  1 + 3 + MPI_MAX / 2 + 1 | 
|  | *      prime2            INTEGER,                  1 + 3 + MPI_MAX / 2 + 1 | 
|  | *      exponent1         INTEGER,                  1 + 3 + MPI_MAX / 2 + 1 | 
|  | *      exponent2         INTEGER,                  1 + 3 + MPI_MAX / 2 + 1 | 
|  | *      coefficient       INTEGER,                  1 + 3 + MPI_MAX / 2 + 1 | 
|  | *      otherPrimeInfos   OtherPrimeInfos OPTIONAL  0 (not supported) | 
|  | *  } | 
|  | */ | 
|  | #define MPI_MAX_SIZE_2          (MBEDTLS_MPI_MAX_SIZE / 2 + \ | 
|  | MBEDTLS_MPI_MAX_SIZE % 2) | 
|  | #define RSA_PRV_DER_MAX_BYTES   (47 + 3 * MBEDTLS_MPI_MAX_SIZE \ | 
|  | + 5 * MPI_MAX_SIZE_2) | 
|  |  | 
|  | #else /* MBEDTLS_RSA_C */ | 
|  |  | 
|  | #define RSA_PUB_DER_MAX_BYTES   0 | 
|  | #define RSA_PRV_DER_MAX_BYTES   0 | 
|  |  | 
|  | #endif /* MBEDTLS_RSA_C */ | 
|  |  | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | /* | 
|  | * EC public keys: | 
|  | *  SubjectPublicKeyInfo  ::=  SEQUENCE  {      1 + 2 | 
|  | *    algorithm         AlgorithmIdentifier,    1 + 1 (sequence) | 
|  | *                                            + 1 + 1 + 7 (ec oid) | 
|  | *                                            + 1 + 1 + 9 (namedCurve oid) | 
|  | *    subjectPublicKey  BIT STRING              1 + 2 + 1               [1] | 
|  | *                                            + 1 (point format)        [1] | 
|  | *                                            + 2 * ECP_MAX (coords)    [1] | 
|  | *  } | 
|  | */ | 
|  | #define ECP_PUB_DER_MAX_BYTES   (30 + 2 * MBEDTLS_ECP_MAX_BYTES) | 
|  |  | 
|  | /* | 
|  | * EC private keys: | 
|  | * ECPrivateKey ::= SEQUENCE {                  1 + 2 | 
|  | *      version        INTEGER ,                1 + 1 + 1 | 
|  | *      privateKey     OCTET STRING,            1 + 1 + ECP_MAX | 
|  | *      parameters [0] ECParameters OPTIONAL,   1 + 1 + (1 + 1 + 9) | 
|  | *      publicKey  [1] BIT STRING OPTIONAL      1 + 2 + [1] above | 
|  | *    } | 
|  | */ | 
|  | #define ECP_PRV_DER_MAX_BYTES   (29 + 3 * MBEDTLS_ECP_MAX_BYTES) | 
|  |  | 
|  | #else /* MBEDTLS_ECP_C */ | 
|  |  | 
|  | #define ECP_PUB_DER_MAX_BYTES   0 | 
|  | #define ECP_PRV_DER_MAX_BYTES   0 | 
|  |  | 
|  | #endif /* MBEDTLS_ECP_C */ | 
|  |  | 
|  | #define PUB_DER_MAX_BYTES   (RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \ | 
|  | RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES) | 
|  | #define PRV_DER_MAX_BYTES   (RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \ | 
|  | RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES) | 
|  |  | 
|  | int mbedtls_pk_write_pubkey_pem(mbedtls_pk_context *key, unsigned char *buf, size_t size) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | unsigned char output_buf[PUB_DER_MAX_BYTES]; | 
|  | size_t olen = 0; | 
|  |  | 
|  | PK_VALIDATE_RET(key != NULL); | 
|  | PK_VALIDATE_RET(buf != NULL || size == 0); | 
|  |  | 
|  | if ((ret = mbedtls_pk_write_pubkey_der(key, output_buf, | 
|  | sizeof(output_buf))) < 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY, | 
|  | output_buf + sizeof(output_buf) - ret, | 
|  | ret, buf, size, &olen)) != 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | int mbedtls_pk_write_key_pem(mbedtls_pk_context *key, unsigned char *buf, size_t size) | 
|  | { | 
|  | int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | 
|  | unsigned char output_buf[PRV_DER_MAX_BYTES]; | 
|  | const char *begin, *end; | 
|  | size_t olen = 0; | 
|  |  | 
|  | PK_VALIDATE_RET(key != NULL); | 
|  | PK_VALIDATE_RET(buf != NULL || size == 0); | 
|  |  | 
|  | if ((ret = mbedtls_pk_write_key_der(key, output_buf, sizeof(output_buf))) < 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | #if defined(MBEDTLS_RSA_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) { | 
|  | begin = PEM_BEGIN_PRIVATE_KEY_RSA; | 
|  | end = PEM_END_PRIVATE_KEY_RSA; | 
|  | } else | 
|  | #endif | 
|  | #if defined(MBEDTLS_ECP_C) | 
|  | if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) { | 
|  | begin = PEM_BEGIN_PRIVATE_KEY_EC; | 
|  | end = PEM_END_PRIVATE_KEY_EC; | 
|  | } else | 
|  | #endif | 
|  | return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE; | 
|  |  | 
|  | if ((ret = mbedtls_pem_write_buffer(begin, end, | 
|  | output_buf + sizeof(output_buf) - ret, | 
|  | ret, buf, size, &olen)) != 0) { | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | return 0; | 
|  | } | 
|  | #endif /* MBEDTLS_PEM_WRITE_C */ | 
|  |  | 
|  | #endif /* MBEDTLS_PK_WRITE_C */ |