pkwrite.c | Explore in Territory

/*
 *  Public Key layer for writing key files and structures
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */

#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 "pk_internal.h"

#include <string.h>

#if defined(MBEDTLS_ECP_C)
#include "mbedtls/bignum.h"
#include "mbedtls/ecp.h"
#include "mbedtls/platform_util.h"
#endif
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
#include "pk_internal.h"
#endif
#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_HAVE_ECC_KEYS)
#include "pkwrite.h"
#endif
#if defined(MBEDTLS_PEM_WRITE_C)
#include "mbedtls/pem.h"
#endif
#if defined(MBEDTLS_RSA_C)
#include "rsa_internal.h"
#endif

#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "psa/crypto.h"
#include "psa_util_internal.h"
#endif
#include "mbedtls/platform.h"

/* Helpers for properly sizing buffers aimed at holding public keys or
 * key-pairs based on build symbols. */
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
#define PK_MAX_EC_PUBLIC_KEY_SIZE …
#define PK_MAX_EC_KEY_PAIR_SIZE …
#elif defined(MBEDTLS_USE_PSA_CRYPTO)
#define PK_MAX_EC_PUBLIC_KEY_SIZE …
#define PK_MAX_EC_KEY_PAIR_SIZE …
#else
#define PK_MAX_EC_PUBLIC_KEY_SIZE …
#define PK_MAX_EC_KEY_PAIR_SIZE …
#endif

/******************************************************************************
 * Internal functions for RSA keys.
 ******************************************************************************/
#if defined(MBEDTLS_RSA_C)
static int pk_write_rsa_der(unsigned char **p, unsigned char *buf,
                            const mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_RSA_C */

/******************************************************************************
 * Internal functions for EC keys.
 ******************************************************************************/
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
static int pk_write_ec_pubkey(unsigned char **p, unsigned char *start,
                              const mbedtls_pk_context *pk)
{
    size_t len = 0;
    uint8_t buf[PK_MAX_EC_PUBLIC_KEY_SIZE];

    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
        if (psa_export_public_key(pk->priv_id, buf, sizeof(buf), &len) != PSA_SUCCESS) {
            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
        }
    } else {
        len = pk->pub_raw_len;
        memcpy(buf, pk->pub_raw, len);
    }

    if (*p < start || (size_t) (*p - start) < len) {
        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
    }

    *p -= len;
    memcpy(*p, buf, len);

    return (int) len;
}
#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
static int pk_write_ec_pubkey(unsigned char **p, unsigned char *start,
                              const mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */

/*
 * privateKey  OCTET STRING -- always of length ceil(log2(n)/8)
 */
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
static int pk_write_ec_private(unsigned char **p, unsigned char *start,
                               const mbedtls_pk_context *pk)
{
    size_t byte_length;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char tmp[PK_MAX_EC_KEY_PAIR_SIZE];
    psa_status_t status;

    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
        status = psa_export_key(pk->priv_id, tmp, sizeof(tmp), &byte_length);
        if (status != PSA_SUCCESS) {
            ret = PSA_PK_ECDSA_TO_MBEDTLS_ERR(status);
            return ret;
        }
    } else {
        status = psa_export_key(pk->priv_id, tmp, sizeof(tmp), &byte_length);
        if (status != PSA_SUCCESS) {
            ret = PSA_PK_ECDSA_TO_MBEDTLS_ERR(status);
            goto exit;
        }
    }

    ret = mbedtls_asn1_write_octet_string(p, start, tmp, byte_length);
exit:
    mbedtls_platform_zeroize(tmp, sizeof(tmp));
    return ret;
}
#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
static int pk_write_ec_private(unsigned char **p, unsigned char *start,
                               const mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */

/*
 * ECParameters ::= CHOICE {
 *   namedCurve         OBJECT IDENTIFIER
 * }
 */
static int pk_write_ec_param(unsigned char **p, unsigned char *start,
                             mbedtls_ecp_group_id grp_id)
{ … }

#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
/*
 * RFC8410 section 7
 *
 * OneAsymmetricKey ::= SEQUENCE {
 *    version Version,
 *    privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
 *    privateKey PrivateKey,
 *    attributes [0] IMPLICIT Attributes OPTIONAL,
 *    ...,
 *    [[2: publicKey [1] IMPLICIT PublicKey OPTIONAL ]],
 *    ...
 * }
 * ...
 * CurvePrivateKey ::= OCTET STRING
 */
static int pk_write_ec_rfc8410_der(unsigned char **p, unsigned char *buf,
                                   const mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */

/*
 * 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
 *    }
 */
static int pk_write_ec_der(unsigned char **p, unsigned char *buf,
                           const mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */

/******************************************************************************
 * Internal functions for Opaque keys.
 ******************************************************************************/
#if defined(MBEDTLS_USE_PSA_CRYPTO)
static int pk_write_opaque_pubkey(unsigned char **p, unsigned char *start,
                                  const mbedtls_pk_context *pk)
{
    size_t buffer_size;
    size_t len = 0;

    if (*p < start) {
        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
    }

    buffer_size = (size_t) (*p - start);
    if (psa_export_public_key(pk->priv_id, start, buffer_size,
                              &len) != PSA_SUCCESS) {
        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
    }

    *p -= len;
    memmove(*p, start, len);

    return (int) len;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */

/******************************************************************************
 * Generic helpers
 ******************************************************************************/

/* Extend the public mbedtls_pk_get_type() by getting key type also in case of
 * opaque keys. */
static mbedtls_pk_type_t pk_get_type_ext(const mbedtls_pk_context *pk)
{ … }

/******************************************************************************
 * Public functions for writing private/public DER keys.
 ******************************************************************************/
int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start,
                            const mbedtls_pk_context *key)
{ … }

int mbedtls_pk_write_pubkey_der(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
{ … }

int mbedtls_pk_write_key_der(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
{ … }

/******************************************************************************
 * Public functions for wrinting private/public PEM keys.
 ******************************************************************************/
#if defined(MBEDTLS_PEM_WRITE_C)

#define PUB_DER_MAX_BYTES …
#define PRV_DER_MAX_BYTES …

int mbedtls_pk_write_pubkey_pem(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
{ … }

int mbedtls_pk_write_key_pem(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
{ … }
#endif /* MBEDTLS_PEM_WRITE_C */

#endif /* MBEDTLS_PK_WRITE_C */
godot/thirdparty/mbedtls/library/pkwrite.c
