cmac_prov.c

/*
 * Copyright 2018-2024 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * CMAC low level APIs are deprecated for public use, but still ok for internal
 * use.
 */
#include "internal/deprecated.h"

#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
#include <openssl/params.h>
#include <openssl/evp.h>
#include <openssl/cmac.h>
#include <openssl/err.h>
#include <openssl/proverr.h>

#include "prov/securitycheck.h"
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/provider_util.h"
#include "prov/providercommon.h"
#include "crypto/cmac.h"

/*
 * Forward declaration of everything implemented here.  This is not strictly
 * necessary for the compiler, but provides an assurance that the signatures
 * of the functions in the dispatch table are correct.
 */
static OSSL_FUNC_mac_newctx_fn cmac_new;
static OSSL_FUNC_mac_dupctx_fn cmac_dup;
static OSSL_FUNC_mac_freectx_fn cmac_free;
static OSSL_FUNC_mac_gettable_ctx_params_fn cmac_gettable_ctx_params;
static OSSL_FUNC_mac_get_ctx_params_fn cmac_get_ctx_params;
static OSSL_FUNC_mac_settable_ctx_params_fn cmac_settable_ctx_params;
static OSSL_FUNC_mac_set_ctx_params_fn cmac_set_ctx_params;
static OSSL_FUNC_mac_init_fn cmac_init;
static OSSL_FUNC_mac_update_fn cmac_update;
static OSSL_FUNC_mac_final_fn cmac_final;

/* local CMAC data */

struct cmac_data_st {
    void *provctx;
    CMAC_CTX *ctx;
    PROV_CIPHER cipher;
    OSSL_FIPS_IND_DECLARE
};

static void *cmac_new(void *provctx)
{
    struct cmac_data_st *macctx;

    if (!ossl_prov_is_running())
        return NULL;

    if ((macctx = OPENSSL_zalloc(sizeof(*macctx))) == NULL
        || (macctx->ctx = CMAC_CTX_new()) == NULL) {
        OPENSSL_free(macctx);
        macctx = NULL;
    } else {
        macctx->provctx = provctx;
        OSSL_FIPS_IND_INIT(macctx)
    }

    return macctx;
}

static void cmac_free(void *vmacctx)
{
    struct cmac_data_st *macctx = vmacctx;

    if (macctx != NULL) {
        CMAC_CTX_free(macctx->ctx);
        ossl_prov_cipher_reset(&macctx->cipher);
        OPENSSL_free(macctx);
    }
}

static void *cmac_dup(void *vsrc)
{
    struct cmac_data_st *src = vsrc;
    struct cmac_data_st *dst;

    if (!ossl_prov_is_running())
        return NULL;

    dst = cmac_new(src->provctx);
    if (dst == NULL)
        return NULL;
    if (!CMAC_CTX_copy(dst->ctx, src->ctx)
        || !ossl_prov_cipher_copy(&dst->cipher, &src->cipher)) {
        cmac_free(dst);
        return NULL;
    }
    OSSL_FIPS_IND_COPY(dst, src)
    return dst;
}

static size_t cmac_size(void *vmacctx)
{
    struct cmac_data_st *macctx = vmacctx;
    const EVP_CIPHER_CTX *cipherctx = CMAC_CTX_get0_cipher_ctx(macctx->ctx);

    if (EVP_CIPHER_CTX_get0_cipher(cipherctx) == NULL)
        return 0;

    return EVP_CIPHER_CTX_get_block_size(cipherctx);
}

#ifdef FIPS_MODULE
/*
 * TDES Encryption is not approved in FIPS 140-3.
 *
 * In strict approved mode we just fail here (by returning 0).
 * If we are going to bypass it using a FIPS indicator then we need to pass that
 * information down to the cipher also.
 * This function returns the param to pass down in 'p'.
 * state will return OSSL_FIPS_IND_STATE_UNKNOWN if the param has not been set.
 *
 * The name 'OSSL_CIPHER_PARAM_FIPS_ENCRYPT_CHECK' used below matches the
 * key name used by the Triple-DES.
 */
static int tdes_check_param(struct cmac_data_st *macctx, OSSL_PARAM *p,
                            int *state)
{
    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(macctx->provctx);
    const EVP_CIPHER *cipher = ossl_prov_cipher_cipher(&macctx->cipher);

    *state = OSSL_FIPS_IND_STATE_UNKNOWN;
    if (EVP_CIPHER_is_a(cipher, "DES-EDE3-CBC")) {
        if (!OSSL_FIPS_IND_ON_UNAPPROVED(macctx, OSSL_FIPS_IND_SETTABLE0,
                                         libctx, "CMAC", "Triple-DES",
                                         ossl_fips_config_tdes_encrypt_disallowed))
            return 0;
        OSSL_FIPS_IND_GET_PARAM(macctx, p, state, OSSL_FIPS_IND_SETTABLE0,
                                OSSL_CIPHER_PARAM_FIPS_ENCRYPT_CHECK)
    }
    return 1;
}
#endif

static int cmac_setkey(struct cmac_data_st *macctx,
                       const unsigned char *key, size_t keylen)
{
    int rv;
    OSSL_PARAM *p = NULL;
#ifdef FIPS_MODULE
    int state = OSSL_FIPS_IND_STATE_UNKNOWN;
    OSSL_PARAM prms[2] = { OSSL_PARAM_END, OSSL_PARAM_END };

    if (!tdes_check_param(macctx, &prms[0], &state))
        return 0;
    if (state != OSSL_FIPS_IND_STATE_UNKNOWN)
        p = prms;
#endif
    rv = ossl_cmac_init(macctx->ctx, key, keylen,
                        ossl_prov_cipher_cipher(&macctx->cipher),
                        ossl_prov_cipher_engine(&macctx->cipher), p);
    ossl_prov_cipher_reset(&macctx->cipher);
    return rv;
}

static int cmac_init(void *vmacctx, const unsigned char *key,
                     size_t keylen, const OSSL_PARAM params[])
{
    struct cmac_data_st *macctx = vmacctx;

    if (!ossl_prov_is_running() || !cmac_set_ctx_params(macctx, params))
        return 0;
    if (key != NULL)
        return cmac_setkey(macctx, key, keylen);
    /* Reinitialize the CMAC context */
    return CMAC_Init(macctx->ctx, NULL, 0, NULL, NULL);
}

static int cmac_update(void *vmacctx, const unsigned char *data,
                       size_t datalen)
{
    struct cmac_data_st *macctx = vmacctx;

    return CMAC_Update(macctx->ctx, data, datalen);
}

static int cmac_final(void *vmacctx, unsigned char *out, size_t *outl,
                      size_t outsize)
{
    struct cmac_data_st *macctx = vmacctx;

    if (!ossl_prov_is_running())
        return 0;

    return CMAC_Final(macctx->ctx, out, outl);
}

static const OSSL_PARAM known_gettable_ctx_params[] = {
    OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
    OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
    OSSL_FIPS_IND_GETTABLE_CTX_PARAM()
    OSSL_PARAM_END
};
static const OSSL_PARAM *cmac_gettable_ctx_params(ossl_unused void *ctx,
                                                  ossl_unused void *provctx)
{
    return known_gettable_ctx_params;
}

static int cmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
{
    OSSL_PARAM *p;

    if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
            && !OSSL_PARAM_set_size_t(p, cmac_size(vmacctx)))
        return 0;

    if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL
            && !OSSL_PARAM_set_size_t(p, cmac_size(vmacctx)))
        return 0;

    if (!OSSL_FIPS_IND_GET_CTX_PARAM((struct cmac_data_st *)vmacctx, params))
        return 0;
    return 1;
}

static const OSSL_PARAM known_settable_ctx_params[] = {
    OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_CIPHER, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_MAC_PARAM_PROPERTIES, NULL, 0),
    OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
    OSSL_FIPS_IND_SETTABLE_CTX_PARAM(OSSL_CIPHER_PARAM_FIPS_ENCRYPT_CHECK)
    OSSL_PARAM_END
};
static const OSSL_PARAM *cmac_settable_ctx_params(ossl_unused void *ctx,
                                                  ossl_unused void *provctx)
{
    return known_settable_ctx_params;
}

/*
 * ALL parameters should be set before init().
 */
static int cmac_set_ctx_params(void *vmacctx, const OSSL_PARAM params[])
{
    struct cmac_data_st *macctx = vmacctx;
    OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(macctx->provctx);
    const OSSL_PARAM *p;

    if (ossl_param_is_empty(params))
        return 1;

    if (!OSSL_FIPS_IND_SET_CTX_PARAM(macctx,
                                     OSSL_FIPS_IND_SETTABLE0, params,
                                     OSSL_CIPHER_PARAM_FIPS_ENCRYPT_CHECK))
        return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_CIPHER)) != NULL) {
        if (!ossl_prov_cipher_load_from_params(&macctx->cipher, params, ctx))
            return 0;

        if (EVP_CIPHER_get_mode(ossl_prov_cipher_cipher(&macctx->cipher))
            != EVP_CIPH_CBC_MODE) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MODE);
            return 0;
        }
#ifdef FIPS_MODULE
        {
            const EVP_CIPHER *cipher = ossl_prov_cipher_cipher(&macctx->cipher);

            if (!EVP_CIPHER_is_a(cipher, "AES-256-CBC")
                    && !EVP_CIPHER_is_a(cipher, "AES-192-CBC")
                    && !EVP_CIPHER_is_a(cipher, "AES-128-CBC")
                    && !EVP_CIPHER_is_a(cipher, "DES-EDE3-CBC")) {
                ERR_raise(ERR_LIB_PROV, EVP_R_UNSUPPORTED_CIPHER);
                return 0;
            }
        }
#endif
    }

    if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
        if (p->data_type != OSSL_PARAM_OCTET_STRING)
            return 0;
        return cmac_setkey(macctx, p->data, p->data_size);
    }
    return 1;
}

const OSSL_DISPATCH ossl_cmac_functions[] = {
    { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))cmac_new },
    { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))cmac_dup },
    { OSSL_FUNC_MAC_FREECTX, (void (*)(void))cmac_free },
    { OSSL_FUNC_MAC_INIT, (void (*)(void))cmac_init },
    { OSSL_FUNC_MAC_UPDATE, (void (*)(void))cmac_update },
    { OSSL_FUNC_MAC_FINAL, (void (*)(void))cmac_final },
    { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
      (void (*)(void))cmac_gettable_ctx_params },
    { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))cmac_get_ctx_params },
    { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
      (void (*)(void))cmac_settable_ctx_params },
    { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))cmac_set_ctx_params },
    OSSL_DISPATCH_END
};