godot/thirdparty/mbedtls/library/pk.c

/*
 *  Public Key abstraction layer
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */

#include "common.h"

#if defined(MBEDTLS_PK_C)
#include "mbedtls/pk.h"
#include "pk_wrap.h"
#include "pkwrite.h"
#include "pk_internal.h"

#include "mbedtls/platform_util.h"
#include "mbedtls/error.h"

#if defined(MBEDTLS_RSA_C)
#include "mbedtls/rsa.h"
#include "rsa_internal.h"
#endif
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
#include "mbedtls/ecp.h"
#endif
#if defined(MBEDTLS_ECDSA_C)
#include "mbedtls/ecdsa.h"
#endif

#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
#include "psa_util_internal.h"
#include "mbedtls/psa_util.h"
#endif

#include <limits.h>
#include <stdint.h>

#define PSA_EXPORT_KEY_PAIR_OR_PUBLIC_MAX_SIZE …

/*
 * Initialise a mbedtls_pk_context
 */
void mbedtls_pk_init(mbedtls_pk_context *ctx)
{ … }

/*
 * Free (the components of) a mbedtls_pk_context
 */
void mbedtls_pk_free(mbedtls_pk_context *ctx)
{ … }

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/*
 * Initialize a restart context
 */
void mbedtls_pk_restart_init(mbedtls_pk_restart_ctx *ctx)
{
    ctx->pk_info = NULL;
    ctx->rs_ctx = NULL;
}

/*
 * Free the components of a restart context
 */
void mbedtls_pk_restart_free(mbedtls_pk_restart_ctx *ctx)
{
    if (ctx == NULL || ctx->pk_info == NULL ||
        ctx->pk_info->rs_free_func == NULL) {
        return;
    }

    ctx->pk_info->rs_free_func(ctx->rs_ctx);

    ctx->pk_info = NULL;
    ctx->rs_ctx = NULL;
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

/*
 * Get pk_info structure from type
 */
const mbedtls_pk_info_t *mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type)
{ … }

/*
 * Initialise context
 */
int mbedtls_pk_setup(mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info)
{ … }

#if defined(MBEDTLS_USE_PSA_CRYPTO)
/*
 * Initialise a PSA-wrapping context
 */
int mbedtls_pk_setup_opaque(mbedtls_pk_context *ctx,
                            const mbedtls_svc_key_id_t key)
{
    const mbedtls_pk_info_t *info = NULL;
    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
    psa_key_type_t type;

    if (ctx == NULL || ctx->pk_info != NULL) {
        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
    }

    if (PSA_SUCCESS != psa_get_key_attributes(key, &attributes)) {
        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
    }
    type = psa_get_key_type(&attributes);
    psa_reset_key_attributes(&attributes);

#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
    if (PSA_KEY_TYPE_IS_ECC_KEY_PAIR(type)) {
        info = &mbedtls_ecdsa_opaque_info;
    } else
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
    if (type == PSA_KEY_TYPE_RSA_KEY_PAIR) {
        info = &mbedtls_rsa_opaque_info;
    } else {
        return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
    }

    ctx->pk_info = info;
    ctx->priv_id = key;

    return 0;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */

#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
/*
 * Initialize an RSA-alt context
 */
int mbedtls_pk_setup_rsa_alt(mbedtls_pk_context *ctx, void *key,
                             mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
                             mbedtls_pk_rsa_alt_sign_func sign_func,
                             mbedtls_pk_rsa_alt_key_len_func key_len_func)
{ … }
#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */

/*
 * Tell if a PK can do the operations of the given type
 */
int mbedtls_pk_can_do(const mbedtls_pk_context *ctx, mbedtls_pk_type_t type)
{ … }

#if defined(MBEDTLS_USE_PSA_CRYPTO)
/*
 * Tell if a PK can do the operations of the given PSA algorithm
 */
int mbedtls_pk_can_do_ext(const mbedtls_pk_context *ctx, psa_algorithm_t alg,
                          psa_key_usage_t usage)
{
    psa_key_usage_t key_usage;

    /* A context with null pk_info is not set up yet and can't do anything.
     * For backward compatibility, also accept NULL instead of a context
     * pointer. */
    if (ctx == NULL || ctx->pk_info == NULL) {
        return 0;
    }

    /* Filter out non allowed algorithms */
    if (PSA_ALG_IS_ECDSA(alg) == 0 &&
        PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg) == 0 &&
        PSA_ALG_IS_RSA_PSS(alg) == 0 &&
        alg != PSA_ALG_RSA_PKCS1V15_CRYPT &&
        PSA_ALG_IS_ECDH(alg) == 0) {
        return 0;
    }

    /* Filter out non allowed usage flags */
    if (usage == 0 ||
        (usage & ~(PSA_KEY_USAGE_SIGN_HASH |
                   PSA_KEY_USAGE_DECRYPT |
                   PSA_KEY_USAGE_DERIVE)) != 0) {
        return 0;
    }

    /* Wildcard hash is not allowed */
    if (PSA_ALG_IS_SIGN_HASH(alg) &&
        PSA_ALG_SIGN_GET_HASH(alg) == PSA_ALG_ANY_HASH) {
        return 0;
    }

    if (mbedtls_pk_get_type(ctx) != MBEDTLS_PK_OPAQUE) {
        mbedtls_pk_type_t type;

        if (PSA_ALG_IS_ECDSA(alg) || PSA_ALG_IS_ECDH(alg)) {
            type = MBEDTLS_PK_ECKEY;
        } else if (PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg) ||
                   alg == PSA_ALG_RSA_PKCS1V15_CRYPT) {
            type = MBEDTLS_PK_RSA;
        } else if (PSA_ALG_IS_RSA_PSS(alg)) {
            type = MBEDTLS_PK_RSASSA_PSS;
        } else {
            return 0;
        }

        if (ctx->pk_info->can_do(type) == 0) {
            return 0;
        }

        switch (type) {
            case MBEDTLS_PK_ECKEY:
                key_usage = PSA_KEY_USAGE_SIGN_HASH | PSA_KEY_USAGE_DERIVE;
                break;
            case MBEDTLS_PK_RSA:
            case MBEDTLS_PK_RSASSA_PSS:
                key_usage = PSA_KEY_USAGE_SIGN_HASH |
                            PSA_KEY_USAGE_SIGN_MESSAGE |
                            PSA_KEY_USAGE_DECRYPT;
                break;
            default:
                /* Should never happen */
                return 0;
        }

        return (key_usage & usage) == usage;
    }

    psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
    psa_status_t status;

    status = psa_get_key_attributes(ctx->priv_id, &attributes);
    if (status != PSA_SUCCESS) {
        return 0;
    }

    psa_algorithm_t key_alg = psa_get_key_algorithm(&attributes);
    /* Key's enrollment is available only when an Mbed TLS implementation of PSA
     * Crypto is being used, i.e. when MBEDTLS_PSA_CRYPTO_C is defined.
     * Even though we don't officially support using other implementations of PSA
     * Crypto with TLS and X.509 (yet), we try to keep vendor's customizations
     * separated. */
#if defined(MBEDTLS_PSA_CRYPTO_C)
    psa_algorithm_t key_alg2 = psa_get_key_enrollment_algorithm(&attributes);
#endif /* MBEDTLS_PSA_CRYPTO_C */
    key_usage = psa_get_key_usage_flags(&attributes);
    psa_reset_key_attributes(&attributes);

    if ((key_usage & usage) != usage) {
        return 0;
    }

    /*
     * Common case: the key alg [or alg2] only allows alg.
     * This will match PSA_ALG_RSA_PKCS1V15_CRYPT & PSA_ALG_IS_ECDH
     * directly.
     * This would also match ECDSA/RSA_PKCS1V15_SIGN/RSA_PSS with
     * a fixed hash on key_alg [or key_alg2].
     */
    if (alg == key_alg) {
        return 1;
    }
#if defined(MBEDTLS_PSA_CRYPTO_C)
    if (alg == key_alg2) {
        return 1;
    }
#endif /* MBEDTLS_PSA_CRYPTO_C */

    /*
     * If key_alg [or key_alg2] is a hash-and-sign with a wildcard for the hash,
     * and alg is the same hash-and-sign family with any hash,
     * then alg is compliant with this key alg
     */
    if (PSA_ALG_IS_SIGN_HASH(alg)) {
        if (PSA_ALG_IS_SIGN_HASH(key_alg) &&
            PSA_ALG_SIGN_GET_HASH(key_alg) == PSA_ALG_ANY_HASH &&
            (alg & ~PSA_ALG_HASH_MASK) == (key_alg & ~PSA_ALG_HASH_MASK)) {
            return 1;
        }
#if defined(MBEDTLS_PSA_CRYPTO_C)
        if (PSA_ALG_IS_SIGN_HASH(key_alg2) &&
            PSA_ALG_SIGN_GET_HASH(key_alg2) == PSA_ALG_ANY_HASH &&
            (alg & ~PSA_ALG_HASH_MASK) == (key_alg2 & ~PSA_ALG_HASH_MASK)) {
            return 1;
        }
#endif /* MBEDTLS_PSA_CRYPTO_C */
    }

    return 0;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */

#if defined(MBEDTLS_PSA_CRYPTO_CLIENT)
#if defined(MBEDTLS_RSA_C)
static psa_algorithm_t psa_algorithm_for_rsa(const mbedtls_rsa_context *rsa,
                                             int want_crypt)
{ … }
#endif /* MBEDTLS_RSA_C */

int mbedtls_pk_get_psa_attributes(const mbedtls_pk_context *pk,
                                  psa_key_usage_t usage,
                                  psa_key_attributes_t *attributes)
{ … }

#if defined(MBEDTLS_PK_USE_PSA_EC_DATA) || defined(MBEDTLS_USE_PSA_CRYPTO)
static psa_status_t export_import_into_psa(mbedtls_svc_key_id_t old_key_id,
                                           const psa_key_attributes_t *attributes,
                                           mbedtls_svc_key_id_t *new_key_id)
{
    unsigned char key_buffer[PSA_EXPORT_KEY_PAIR_MAX_SIZE];
    size_t key_length = 0;
    psa_status_t status = psa_export_key(old_key_id,
                                         key_buffer, sizeof(key_buffer),
                                         &key_length);
    if (status != PSA_SUCCESS) {
        return status;
    }
    status = psa_import_key(attributes, key_buffer, key_length, new_key_id);
    mbedtls_platform_zeroize(key_buffer, key_length);
    return status;
}

static int copy_into_psa(mbedtls_svc_key_id_t old_key_id,
                         const psa_key_attributes_t *attributes,
                         mbedtls_svc_key_id_t *new_key_id)
{
    /* Normally, we prefer copying: it's more efficient and works even
     * for non-exportable keys. */
    psa_status_t status = psa_copy_key(old_key_id, attributes, new_key_id);
    if (status == PSA_ERROR_NOT_PERMITTED /*missing COPY usage*/ ||
        status == PSA_ERROR_INVALID_ARGUMENT /*incompatible policy*/) {
        /* There are edge cases where copying won't work, but export+import
         * might:
         * - If the old key does not allow PSA_KEY_USAGE_COPY.
         * - If the old key's usage does not allow what attributes wants.
         *   Because the key was intended for use in the pk module, and may
         *   have had a policy chosen solely for what pk needs rather than
         *   based on a detailed understanding of PSA policies, we are a bit
         *   more liberal than psa_copy_key() here.
         */
        /* Here we need to check that the types match, otherwise we risk
         * importing nonsensical data. */
        psa_key_attributes_t old_attributes = PSA_KEY_ATTRIBUTES_INIT;
        status = psa_get_key_attributes(old_key_id, &old_attributes);
        if (status != PSA_SUCCESS) {
            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
        }
        psa_key_type_t old_type = psa_get_key_type(&old_attributes);
        psa_reset_key_attributes(&old_attributes);
        if (old_type != psa_get_key_type(attributes)) {
            return MBEDTLS_ERR_PK_TYPE_MISMATCH;
        }
        status = export_import_into_psa(old_key_id, attributes, new_key_id);
    }
    return PSA_PK_TO_MBEDTLS_ERR(status);
}
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA || MBEDTLS_USE_PSA_CRYPTO */

static int import_pair_into_psa(const mbedtls_pk_context *pk,
                                const psa_key_attributes_t *attributes,
                                mbedtls_svc_key_id_t *key_id)
{ … }

static int import_public_into_psa(const mbedtls_pk_context *pk,
                                  const psa_key_attributes_t *attributes,
                                  mbedtls_svc_key_id_t *key_id)
{ … }

int mbedtls_pk_import_into_psa(const mbedtls_pk_context *pk,
                               const psa_key_attributes_t *attributes,
                               mbedtls_svc_key_id_t *key_id)
{ … }

static int copy_from_psa(mbedtls_svc_key_id_t key_id,
                         mbedtls_pk_context *pk,
                         int public_only)
{ … }

int mbedtls_pk_copy_from_psa(mbedtls_svc_key_id_t key_id,
                             mbedtls_pk_context *pk)
{ … }

int mbedtls_pk_copy_public_from_psa(mbedtls_svc_key_id_t key_id,
                                    mbedtls_pk_context *pk)
{ … }
#endif /* MBEDTLS_PSA_CRYPTO_CLIENT */

/*
 * Helper for mbedtls_pk_sign and mbedtls_pk_verify
 */
static inline int pk_hashlen_helper(mbedtls_md_type_t md_alg, size_t *hash_len)
{ … }

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/*
 * Helper to set up a restart context if needed
 */
static int pk_restart_setup(mbedtls_pk_restart_ctx *ctx,
                            const mbedtls_pk_info_t *info)
{
    /* Don't do anything if already set up or invalid */
    if (ctx == NULL || ctx->pk_info != NULL) {
        return 0;
    }

    /* Should never happen when we're called */
    if (info->rs_alloc_func == NULL || info->rs_free_func == NULL) {
        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
    }

    if ((ctx->rs_ctx = info->rs_alloc_func()) == NULL) {
        return MBEDTLS_ERR_PK_ALLOC_FAILED;
    }

    ctx->pk_info = info;

    return 0;
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

/*
 * Verify a signature (restartable)
 */
int mbedtls_pk_verify_restartable(mbedtls_pk_context *ctx,
                                  mbedtls_md_type_t md_alg,
                                  const unsigned char *hash, size_t hash_len,
                                  const unsigned char *sig, size_t sig_len,
                                  mbedtls_pk_restart_ctx *rs_ctx)
{ … }

/*
 * Verify a signature
 */
int mbedtls_pk_verify(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                      const unsigned char *hash, size_t hash_len,
                      const unsigned char *sig, size_t sig_len)
{ … }

/*
 * Verify a signature with options
 */
int mbedtls_pk_verify_ext(mbedtls_pk_type_t type, const void *options,
                          mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                          const unsigned char *hash, size_t hash_len,
                          const unsigned char *sig, size_t sig_len)
{ … }

/*
 * Make a signature (restartable)
 */
int mbedtls_pk_sign_restartable(mbedtls_pk_context *ctx,
                                mbedtls_md_type_t md_alg,
                                const unsigned char *hash, size_t hash_len,
                                unsigned char *sig, size_t sig_size, size_t *sig_len,
                                int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
                                mbedtls_pk_restart_ctx *rs_ctx)
{ … }

/*
 * Make a signature
 */
int mbedtls_pk_sign(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                    const unsigned char *hash, size_t hash_len,
                    unsigned char *sig, size_t sig_size, size_t *sig_len,
                    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{ … }

/*
 * Make a signature given a signature type.
 */
int mbedtls_pk_sign_ext(mbedtls_pk_type_t pk_type,
                        mbedtls_pk_context *ctx,
                        mbedtls_md_type_t md_alg,
                        const unsigned char *hash, size_t hash_len,
                        unsigned char *sig, size_t sig_size, size_t *sig_len,
                        int (*f_rng)(void *, unsigned char *, size_t),
                        void *p_rng)
{ … }

/*
 * Decrypt message
 */
int mbedtls_pk_decrypt(mbedtls_pk_context *ctx,
                       const unsigned char *input, size_t ilen,
                       unsigned char *output, size_t *olen, size_t osize,
                       int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{ … }

/*
 * Encrypt message
 */
int mbedtls_pk_encrypt(mbedtls_pk_context *ctx,
                       const unsigned char *input, size_t ilen,
                       unsigned char *output, size_t *olen, size_t osize,
                       int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{ … }

/*
 * Check public-private key pair
 */
int mbedtls_pk_check_pair(const mbedtls_pk_context *pub,
                          const mbedtls_pk_context *prv,
                          int (*f_rng)(void *, unsigned char *, size_t),
                          void *p_rng)
{ … }

/*
 * Get key size in bits
 */
size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context *ctx)
{ … }

/*
 * Export debug information
 */
int mbedtls_pk_debug(const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items)
{ … }

/*
 * Access the PK type name
 */
const char *mbedtls_pk_get_name(const mbedtls_pk_context *ctx)
{ … }

/*
 * Access the PK type
 */
mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context *ctx)
{ … }

#endif /* MBEDTLS_PK_C */