/*

 * Copyright 2018-2025 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

 */

/*

 * HMAC low level APIs are deprecated for public use, but still ok for internal

 * use.

 */

#include "internal/deprecated.h"

#include <stdlib.h>

#include <stdarg.h>

#include <string.h>

#include <openssl/hmac.h>

#include <openssl/evp.h>

#include <openssl/kdf.h>

#include <openssl/core_names.h>

#include <openssl/proverr.h>

#include "internal/cryptlib.h"

#include "internal/numbers.h"

#include "crypto/evp.h"

#include "prov/provider_ctx.h"

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/provider_util.h"

#include "prov/securitycheck.h"

#include "providers/implementations/kdfs/pbkdf2.inc"

/* Constants specified in SP800-132 */

#define KDF_PBKDF2_MIN_KEY_LEN_BITS 112

#define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF

#define KDF_PBKDF2_MIN_ITERATIONS 1000

#define KDF_PBKDF2_MIN_SALT_LEN   (128 / 8)

/*

 * The Implementation Guidance for FIPS 140-3 says in section D.N

 * "Password-Based Key Derivation for Storage Applications" that "the vendor

 * shall document in the module's Security Policy the length of

 * a password/passphrase used in key derivation and establish an upper bound

 * for the probability of having this parameter guessed at random. This

 * probability shall take into account not only the length of the

 * password/passphrase, but also the difficulty of guessing it. The decision on

 * the minimum length of a password used for key derivation is the vendor's,

 * but the vendor shall at a minimum informally justify the decision."

 *

 * ACVP may assume 8, most FIPS modules choose 8, BC-FJA chose 14.

 *

 * Allow setting this for default provider too, in case consistency is

 * desired for FIPS and Default providers. Because password being

 * accepted on one system, but not the other, is very confusing.

 */

#ifndef KDF_PBKDF2_MIN_PASSWORD_LEN

# ifdef FIPS_MODULE

#  define KDF_PBKDF2_MIN_PASSWORD_LEN (8)

# else

#  define KDF_PBKDF2_MIN_PASSWORD_LEN (1)

# endif

#endif

static OSSL_FUNC_kdf_newctx_fn kdf_pbkdf2_new;

static OSSL_FUNC_kdf_dupctx_fn kdf_pbkdf2_dup;

static OSSL_FUNC_kdf_freectx_fn kdf_pbkdf2_free;

static OSSL_FUNC_kdf_reset_fn kdf_pbkdf2_reset;

static OSSL_FUNC_kdf_derive_fn kdf_pbkdf2_derive;

static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_pbkdf2_settable_ctx_params;

static OSSL_FUNC_kdf_set_ctx_params_fn kdf_pbkdf2_set_ctx_params;

static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_pbkdf2_gettable_ctx_params;

static OSSL_FUNC_kdf_get_ctx_params_fn kdf_pbkdf2_get_ctx_params;

typedef struct {

    void *provctx;

    unsigned char *pass;

    size_t pass_len;

    unsigned char *salt;

    size_t salt_len;

    uint64_t iter;

    PROV_DIGEST digest;

    int lower_bound_checks;

    OSSL_FIPS_IND_DECLARE

} KDF_PBKDF2;

static int pbkdf2_derive(KDF_PBKDF2 *ctx, const char *pass, size_t passlen,

                         const unsigned char *salt, int saltlen, uint64_t iter,

                         const EVP_MD *digest, unsigned char *key,

                         size_t keylen, int lower_bound_checks);

static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx);

static void *kdf_pbkdf2_new_no_init(void *provctx)

{

    KDF_PBKDF2 *ctx;

    if (!ossl_prov_is_running())

        return NULL;

    ctx = OPENSSL_zalloc(sizeof(*ctx));

    if (ctx == NULL)

        return NULL;

    ctx->provctx = provctx;

    OSSL_FIPS_IND_INIT(ctx);

    return ctx;

}

static void *kdf_pbkdf2_new(void *provctx)

{

    KDF_PBKDF2 *ctx = kdf_pbkdf2_new_no_init(provctx);

    if (ctx != NULL)

        kdf_pbkdf2_init(ctx);

    return ctx;

}

static void kdf_pbkdf2_cleanup(KDF_PBKDF2 *ctx)

{

    ossl_prov_digest_reset(&ctx->digest);

#ifdef OPENSSL_PEDANTIC_ZEROIZATION

    OPENSSL_clear_free(ctx->salt, ctx->salt_len);

#else

    OPENSSL_free(ctx->salt);

#endif

    OPENSSL_clear_free(ctx->pass, ctx->pass_len);

    memset(ctx, 0, sizeof(*ctx));

}

static void kdf_pbkdf2_free(void *vctx)

{

    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;

    if (ctx != NULL) {

        kdf_pbkdf2_cleanup(ctx);

        OPENSSL_free(ctx);

    }

}

static void kdf_pbkdf2_reset(void *vctx)

{

    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;

    void *provctx = ctx->provctx;

    kdf_pbkdf2_cleanup(ctx);

    ctx->provctx = provctx;

    kdf_pbkdf2_init(ctx);

}

static void *kdf_pbkdf2_dup(void *vctx)

{

    const KDF_PBKDF2 *src = (const KDF_PBKDF2 *)vctx;

    KDF_PBKDF2 *dest;

    /* We need a new PBKDF2 object but uninitialised since we're filling it */

    dest = kdf_pbkdf2_new_no_init(src->provctx);

    if (dest != NULL) {

        if (!ossl_prov_memdup(src->salt, src->salt_len,

                              &dest->salt, &dest->salt_len)

                || !ossl_prov_memdup(src->pass, src->pass_len,

                                     &dest->pass, &dest->pass_len)

                || !ossl_prov_digest_copy(&dest->digest, &src->digest))

            goto err;

        dest->iter = src->iter;

        dest->lower_bound_checks = src->lower_bound_checks;

        OSSL_FIPS_IND_COPY(dest, src)

    }

    return dest;

 err:

    kdf_pbkdf2_free(dest);

    return NULL;

}

static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx)

{

    OSSL_PARAM param;

    OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);

    param = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,

                                             SN_sha1, 0);

    if (!ossl_prov_digest_load(&ctx->digest, &param, NULL, provctx))

        /* This is an error, but there is no way to indicate such directly */

        ossl_prov_digest_reset(&ctx->digest);

    ctx->iter = PKCS5_DEFAULT_ITER;

#ifdef FIPS_MODULE

    ctx->lower_bound_checks = 1;

#else

    ctx->lower_bound_checks = 0;

#endif

}

static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,

                             const OSSL_PARAM *p)

{

    OPENSSL_clear_free(*buffer, *buflen);

    *buffer = NULL;

    *buflen = 0;

    if (p->data_size == 0) {

        if ((*buffer = OPENSSL_malloc(1)) == NULL)

            return 0;

    } else if (p->data != NULL) {

        if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))

            return 0;

    }

    return 1;

}

static int pbkdf2_lower_bound_check_passed(int saltlen, uint64_t iter,

                                           size_t keylen, size_t passlen,

                                           int *error, const char **desc)

{

    if (passlen < KDF_PBKDF2_MIN_PASSWORD_LEN) {

        *error = PROV_R_PASSWORD_STRENGTH_TOO_WEAK;

        if (desc != NULL)

            *desc = "Weak password";

        return 0;

    }

    if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {

        *error = PROV_R_KEY_SIZE_TOO_SMALL;

        if (desc != NULL)

            *desc = "Key size";

        return 0;

    }

    if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {

        *error = PROV_R_INVALID_SALT_LENGTH;

        if (desc != NULL)

            *desc = "Salt size";

        return 0;

    }

    if (iter < KDF_PBKDF2_MIN_ITERATIONS) {

        *error = PROV_R_INVALID_ITERATION_COUNT;

        if (desc != NULL)

            *desc = "Iteration count";

        return 0;

    }

    return 1;

}

#ifdef FIPS_MODULE

static int fips_lower_bound_check_passed(KDF_PBKDF2 *ctx, int saltlen,

                                         uint64_t iter, size_t keylen,

                                         size_t passlen)

{

    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);

    int error = 0;

    const char *desc = NULL;

    int approved = pbkdf2_lower_bound_check_passed(saltlen, iter, keylen,

                                                   passlen, &error, &desc);

    if (!approved) {

        if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0, libctx,

                                         "PBKDF2", desc,

                                         ossl_fips_config_pbkdf2_lower_bound_check)) {

            ERR_raise(ERR_LIB_PROV, error);

            return 0;

        }

    }

    return 1;

}

#endif

static int lower_bound_check_passed(KDF_PBKDF2 *ctx, int saltlen, uint64_t iter,

                                    size_t keylen, size_t passlen,

                                    int lower_bound_checks)

{

#ifdef FIPS_MODULE

    if (!fips_lower_bound_check_passed(ctx, saltlen, iter, keylen, passlen))

        return 0;

#else

    if (lower_bound_checks) {

        int error = 0;

        int passed = pbkdf2_lower_bound_check_passed(saltlen, iter, keylen,

                                                     passlen, &error, NULL);

        if (!passed) {

            ERR_raise(ERR_LIB_PROV, error);

            return 0;

        }

    } else if (iter < 1) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);

        return 0;

    }

#endif

    return 1;

}

static int kdf_pbkdf2_derive(void *vctx, unsigned char *key, size_t keylen,

                             const OSSL_PARAM params[])

{

    KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;

    const EVP_MD *md;

    if (!ossl_prov_is_running() || !kdf_pbkdf2_set_ctx_params(ctx, params))

        return 0;

    if (ctx->pass == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);

        return 0;

    }

    if (ctx->salt == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);

        return 0;

    }

    md = ossl_prov_digest_md(&ctx->digest);

    return pbkdf2_derive(ctx, (char *)ctx->pass, ctx->pass_len,

                         ctx->salt, (int)ctx->salt_len, ctx->iter,

                         md, key, keylen, ctx->lower_bound_checks);

}

static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])

{

    struct pbkdf2_set_ctx_params_st p;

    KDF_PBKDF2 *ctx = vctx;

    OSSL_LIB_CTX *provctx;

    int pkcs5;

    uint64_t iter;

    const EVP_MD *md;

    if (ctx == NULL || !pbkdf2_set_ctx_params_decoder(params, &p))

        return 0;

    provctx = PROV_LIBCTX_OF(ctx->provctx);

    if (p.digest != NULL) {

        if (!ossl_prov_digest_load(&ctx->digest, p.digest, p.propq, provctx))

            return 0;

        md = ossl_prov_digest_md(&ctx->digest);

        if (EVP_MD_xof(md)) {

            ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);

            return 0;

        }

    }

    if (p.pkcs5 != NULL) {

        if (!OSSL_PARAM_get_int(p.pkcs5, &pkcs5))

            return 0;

        ctx->lower_bound_checks = pkcs5 == 0;

#ifdef FIPS_MODULE

        ossl_FIPS_IND_set_settable(OSSL_FIPS_IND_GET(ctx),

                                   OSSL_FIPS_IND_SETTABLE0,

                                   ctx->lower_bound_checks);

#endif

    }

    if (p.pw != NULL) {

        if (ctx->lower_bound_checks != 0

            && p.pw->data_size < KDF_PBKDF2_MIN_PASSWORD_LEN) {

            ERR_raise(ERR_LIB_PROV, PROV_R_PASSWORD_STRENGTH_TOO_WEAK);

            return 0;

        }

        if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p.pw))

            return 0;

    }

    if (p.salt != NULL) {

        if (!lower_bound_check_passed(ctx, (int)p.salt->data_size, UINT64_MAX, SIZE_MAX,

                                      SIZE_MAX, ctx->lower_bound_checks))

            return 0;

        if (!pbkdf2_set_membuf(&ctx->salt, &ctx->salt_len, p.salt))

            return 0;

    }

    if (p.iter != NULL) {

        if (!OSSL_PARAM_get_uint64(p.iter, &iter))

            return 0;

        if (!lower_bound_check_passed(ctx, INT_MAX, iter, SIZE_MAX,

                                      SIZE_MAX, ctx->lower_bound_checks))

            return 0;

        ctx->iter = iter;

    }

    return 1;

}

static const OSSL_PARAM *kdf_pbkdf2_settable_ctx_params(ossl_unused void *ctx,

                                                        ossl_unused void *p_ctx)

{

    return pbkdf2_set_ctx_params_list;

}

static int kdf_pbkdf2_get_ctx_params(void *vctx, OSSL_PARAM params[])

{

    KDF_PBKDF2 *ctx = vctx;

    struct pbkdf2_get_ctx_params_st p;

    if (ctx == NULL || !pbkdf2_get_ctx_params_decoder(params, &p))

        return 0;

    if (p.size != NULL && !OSSL_PARAM_set_size_t(p.size, SIZE_MAX))

            return 0;

    if (!OSSL_FIPS_IND_GET_CTX_FROM_PARAM(ctx, p.ind))

        return 0;

    return 1;

}

static const OSSL_PARAM *kdf_pbkdf2_gettable_ctx_params(ossl_unused void *ctx,

                                                        ossl_unused void *p_ctx)

{

    return pbkdf2_get_ctx_params_list;

}

const OSSL_DISPATCH ossl_kdf_pbkdf2_functions[] = {

    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_pbkdf2_new },

    { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_pbkdf2_dup },

    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_pbkdf2_free },

    { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_pbkdf2_reset },

    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_pbkdf2_derive },

    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,

      (void(*)(void))kdf_pbkdf2_settable_ctx_params },

    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_set_ctx_params },

    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,

      (void(*)(void))kdf_pbkdf2_gettable_ctx_params },

    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_get_ctx_params },

    OSSL_DISPATCH_END

};

/*

 * This is an implementation of PKCS#5 v2.0 password based encryption key

 * derivation function PBKDF2. SHA1 version verified against test vectors

 * posted by Peter Gutmann to the PKCS-TNG mailing list.

 *

 * The constraints specified by SP800-132 have been added i.e.

 *  - Check the range of the key length.

 *  - Minimum iteration count of 1000.

 *  - Randomly-generated portion of the salt shall be at least 128 bits.

 */

static int pbkdf2_derive(KDF_PBKDF2 *ctx, const char *pass, size_t passlen,

                         const unsigned char *salt, int saltlen, uint64_t iter,

                         const EVP_MD *digest, unsigned char *key,

                         size_t keylen, int lower_bound_checks)

{

    int ret = 0;

    unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];

    int cplen, k, tkeylen, mdlen;

    uint64_t j;

    unsigned long i = 1;

    HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;

    mdlen = EVP_MD_get_size(digest);

    if (mdlen <= 0)

        return 0;

    /*

     * This check should always be done because keylen / mdlen >= (2^32 - 1)

     * results in an overflow of the loop counter 'i'.

     */

    if ((keylen / mdlen) >= KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);

        return 0;

    }

    if (!lower_bound_check_passed(ctx, saltlen, iter, keylen, passlen, lower_bound_checks))

        return 0;

    hctx_tpl = HMAC_CTX_new();

    if (hctx_tpl == NULL)

        return 0;

    p = key;

    tkeylen = (int)keylen;

    if (!HMAC_Init_ex(hctx_tpl, pass, (int)passlen, digest, NULL))

        goto err;

    hctx = HMAC_CTX_new();

    if (hctx == NULL)

        goto err;

    while (tkeylen) {

        if (tkeylen > mdlen)

            cplen = mdlen;

        else

            cplen = tkeylen;

        /*

         * We are unlikely to ever use more than 256 blocks (5120 bits!) but

         * just in case...

         */

        itmp[0] = (unsigned char)((i >> 24) & 0xff);

        itmp[1] = (unsigned char)((i >> 16) & 0xff);

        itmp[2] = (unsigned char)((i >> 8) & 0xff);

        itmp[3] = (unsigned char)(i & 0xff);

        if (!HMAC_CTX_copy(hctx, hctx_tpl))

            goto err;

        if (!HMAC_Update(hctx, salt, saltlen)

                || !HMAC_Update(hctx, itmp, 4)

                || !HMAC_Final(hctx, digtmp, NULL))

            goto err;

        memcpy(p, digtmp, cplen);

        for (j = 1; j < iter; j++) {

            if (!HMAC_CTX_copy(hctx, hctx_tpl))

                goto err;

            if (!HMAC_Update(hctx, digtmp, mdlen)

                    || !HMAC_Final(hctx, digtmp, NULL))

                goto err;

            for (k = 0; k < cplen; k++)

                p[k] ^= digtmp[k];

        }

        tkeylen -= cplen;

        i++;

        p += cplen;

    }

    ret = 1;

err:

    HMAC_CTX_free(hctx);

    HMAC_CTX_free(hctx_tpl);

    return ret;

}