/src/openssl30/providers/implementations/kdfs/sskdf.c

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/*
 * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2019, Oracle and/or its affiliates.  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
 */

/*
 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
 * Section 4.1.
 *
 * The Single Step KDF algorithm is given by:
 *
 * Result(0) = empty bit string (i.e., the null string).
 * For i = 1 to reps, do the following:
 *   Increment counter by 1.
 *   Result(i) = Result(i - 1) || H(counter || Z || FixedInfo).
 * DKM = LeftmostBits(Result(reps), L))
 *
 * NOTES:
 *   Z is a shared secret required to produce the derived key material.
 *   counter is a 4 byte buffer.
 *   FixedInfo is a bit string containing context specific data.
 *   DKM is the output derived key material.
 *   L is the required size of the DKM.
 *   reps = [L / H_outputBits]
 *   H(x) is the auxiliary function that can be either a hash, HMAC or KMAC.
 *   H_outputBits is the length of the output of the auxiliary function H(x).
 *
 * Currently there is not a comprehensive list of test vectors for this
 * algorithm, especially for H(x) = HMAC and H(x) = KMAC.
 * Test vectors for H(x) = Hash are indirectly used by CAVS KAS tests.
 */
#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/params.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"

typedef struct {
    void *provctx;
    EVP_MAC_CTX *macctx;         /* H(x) = HMAC_hash OR H(x) = KMAC */
    PROV_DIGEST digest;          /* H(x) = hash(x) */
    unsigned char *secret;
    size_t secret_len;
    unsigned char *info;
    size_t info_len;
    unsigned char *salt;
    size_t salt_len;
    size_t out_len; /* optional KMAC parameter */
    int is_kmac;
} KDF_SSKDF;

#define SSKDF_MAX_INLEN (1<<30)
#define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
#define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)

/* KMAC uses a Customisation string of 'KDF' */
static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };

static OSSL_FUNC_kdf_newctx_fn sskdf_new;
static OSSL_FUNC_kdf_freectx_fn sskdf_free;
static OSSL_FUNC_kdf_reset_fn sskdf_reset;
static OSSL_FUNC_kdf_derive_fn sskdf_derive;
static OSSL_FUNC_kdf_derive_fn x963kdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn sskdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn sskdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn sskdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn sskdf_get_ctx_params;

/*
 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
 * Section 4. One-Step Key Derivation using H(x) = hash(x)
 * Note: X9.63 also uses this code with the only difference being that the
 * counter is appended to the secret 'z'.
 * i.e.
 *   result[i] = Hash(counter || z || info) for One Step OR
 *   result[i] = Hash(z || counter || info) for X9.63.
 */
static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
                          const unsigned char *z, size_t z_len,
                          const unsigned char *info, size_t info_len,
                          unsigned int append_ctr,
                          unsigned char *derived_key, size_t derived_key_len)
{
    int ret = 0, hlen;
    size_t counter, out_len, len = derived_key_len;
    unsigned char c[4];
    unsigned char mac[EVP_MAX_MD_SIZE];
    unsigned char *out = derived_key;
    EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;

    if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
            || derived_key_len > SSKDF_MAX_INLEN
            || derived_key_len == 0)
        return 0;

    hlen = EVP_MD_get_size(kdf_md);
    if (hlen <= 0)
        return 0;
    out_len = (size_t)hlen;

    ctx = EVP_MD_CTX_create();
    ctx_init = EVP_MD_CTX_create();
    if (ctx == NULL || ctx_init == NULL)
        goto end;

    if (!EVP_DigestInit(ctx_init, kdf_md))
        goto end;

    for (counter = 1;; counter++) {
        c[0] = (unsigned char)((counter >> 24) & 0xff);
        c[1] = (unsigned char)((counter >> 16) & 0xff);
        c[2] = (unsigned char)((counter >> 8) & 0xff);
        c[3] = (unsigned char)(counter & 0xff);

        if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
                && (append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
                && EVP_DigestUpdate(ctx, z, z_len)
                && (!append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
                && EVP_DigestUpdate(ctx, info, info_len)))
            goto end;
        if (len >= out_len) {
            if (!EVP_DigestFinal_ex(ctx, out, NULL))
                goto end;
            out += out_len;
            len -= out_len;
            if (len == 0)
                break;
        } else {
            if (!EVP_DigestFinal_ex(ctx, mac, NULL))
                goto end;
            memcpy(out, mac, len);
            break;
        }
    }
    ret = 1;
end:
    EVP_MD_CTX_destroy(ctx);
    EVP_MD_CTX_destroy(ctx_init);
    OPENSSL_cleanse(mac, sizeof(mac));
    return ret;
}

static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom,
                     size_t custom_len, size_t kmac_out_len,
                     size_t derived_key_len, unsigned char **out)
{
    OSSL_PARAM params[2];

    /* Only KMAC has custom data - so return if not KMAC */
    if (custom == NULL)
        return 1;

    params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
                                                  (void *)custom, custom_len);
    params[1] = OSSL_PARAM_construct_end();

    if (!EVP_MAC_CTX_set_params(ctx, params))
        return 0;

    /* By default only do one iteration if kmac_out_len is not specified */
    if (kmac_out_len == 0)
        kmac_out_len = derived_key_len;
    /* otherwise check the size is valid */
    else if (!(kmac_out_len == derived_key_len
            || kmac_out_len == 20
            || kmac_out_len == 28
            || kmac_out_len == 32
            || kmac_out_len == 48
            || kmac_out_len == 64))
        return 0;

    params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE,
                                            &kmac_out_len);

    if (EVP_MAC_CTX_set_params(ctx, params) <= 0)
        return 0;

    /*
     * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
     * alloc a buffer for this case.
     */
    if (kmac_out_len > EVP_MAX_MD_SIZE) {
        *out = OPENSSL_zalloc(kmac_out_len);
        if (*out == NULL)
            return 0;
    }
    return 1;
}

/*
 * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
 * Section 4. One-Step Key Derivation using MAC: i.e either
 *     H(x) = HMAC-hash(salt, x) OR
 *     H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
 */
static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
                         const unsigned char *kmac_custom,
                         size_t kmac_custom_len, size_t kmac_out_len,
                         const unsigned char *salt, size_t salt_len,
                         const unsigned char *z, size_t z_len,
                         const unsigned char *info, size_t info_len,
                         unsigned char *derived_key, size_t derived_key_len)
{
    int ret = 0;
    size_t counter, out_len, len;
    unsigned char c[4];
    unsigned char mac_buf[EVP_MAX_MD_SIZE];
    unsigned char *out = derived_key;
    EVP_MAC_CTX *ctx = NULL;
    unsigned char *mac = mac_buf, *kmac_buffer = NULL;

    if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
            || derived_key_len > SSKDF_MAX_INLEN
            || derived_key_len == 0)
        return 0;

    if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
                   derived_key_len, &kmac_buffer))
        goto end;
    if (kmac_buffer != NULL)
        mac = kmac_buffer;

    if (!EVP_MAC_init(ctx_init, salt, salt_len, NULL))
        goto end;

    out_len = EVP_MAC_CTX_get_mac_size(ctx_init); /* output size */
    if (out_len <= 0 || (mac == mac_buf && out_len > sizeof(mac_buf)))
        goto end;
    len = derived_key_len;

    for (counter = 1;; counter++) {
        c[0] = (unsigned char)((counter >> 24) & 0xff);
        c[1] = (unsigned char)((counter >> 16) & 0xff);
        c[2] = (unsigned char)((counter >> 8) & 0xff);
        c[3] = (unsigned char)(counter & 0xff);

        ctx = EVP_MAC_CTX_dup(ctx_init);
        if (!(ctx != NULL
                && EVP_MAC_update(ctx, c, sizeof(c))
                && EVP_MAC_update(ctx, z, z_len)
                && EVP_MAC_update(ctx, info, info_len)))
            goto end;
        if (len >= out_len) {
            if (!EVP_MAC_final(ctx, out, NULL, len))
                goto end;
            out += out_len;
            len -= out_len;
            if (len == 0)
                break;
        } else {
            if (!EVP_MAC_final(ctx, mac, NULL, out_len))
                goto end;
            memcpy(out, mac, len);
            break;
        }
        EVP_MAC_CTX_free(ctx);
        ctx = NULL;
    }
    ret = 1;
end:
    if (kmac_buffer != NULL)
        OPENSSL_clear_free(kmac_buffer, kmac_out_len);
    else
        OPENSSL_cleanse(mac_buf, sizeof(mac_buf));

    EVP_MAC_CTX_free(ctx);
    return ret;
}

static void *sskdf_new(void *provctx)
{
    KDF_SSKDF *ctx;

    if (!ossl_prov_is_running())
        return NULL;

    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
    ctx->provctx = provctx;
    return ctx;
}

static void sskdf_reset(void *vctx)
{
    KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
    void *provctx = ctx->provctx;

    EVP_MAC_CTX_free(ctx->macctx);
    ossl_prov_digest_reset(&ctx->digest);
    OPENSSL_clear_free(ctx->secret, ctx->secret_len);
    OPENSSL_clear_free(ctx->info, ctx->info_len);
    OPENSSL_clear_free(ctx->salt, ctx->salt_len);
    memset(ctx, 0, sizeof(*ctx));
    ctx->provctx = provctx;
}

static void sskdf_free(void *vctx)
{
    KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;

    if (ctx != NULL) {
        sskdf_reset(ctx);
        OPENSSL_free(ctx);
    }
}

static int sskdf_set_buffer(unsigned char **out, size_t *out_len,
                            const OSSL_PARAM *p)
{
    if (p->data == NULL || p->data_size == 0)
        return 1;
    OPENSSL_free(*out);
    *out = NULL;
    return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
}

static size_t sskdf_size(KDF_SSKDF *ctx)
{
    int len;
    const EVP_MD *md = NULL;

    if (ctx->is_kmac)
        return SIZE_MAX;

    md = ossl_prov_digest_md(&ctx->digest);
    if (md == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
        return 0;
    }
    len = EVP_MD_get_size(md);
    return (len <= 0) ? 0 : (size_t)len;
}

static int sskdf_derive(void *vctx, unsigned char *key, size_t keylen,
                        const OSSL_PARAM params[])
{
    KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
    const EVP_MD *md;

    if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
        return 0;
    if (ctx->secret == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
        return 0;
    }
    md = ossl_prov_digest_md(&ctx->digest);

    if (ctx->macctx != NULL) {
        /* H(x) = KMAC or H(x) = HMAC */
        int ret;
        const unsigned char *custom = NULL;
        size_t custom_len = 0;
        int default_salt_len;
        EVP_MAC *mac = EVP_MAC_CTX_get0_mac(ctx->macctx);

        if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_HMAC)) {
            /* H(x) = HMAC(x, salt, hash) */
            if (md == NULL) {
                ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
                return 0;
            }
            default_salt_len = EVP_MD_get_size(md);
            if (default_salt_len <= 0)
                return 0;
        } else if (ctx->is_kmac) {
            /* H(x) = KMACzzz(x, salt, custom) */
            custom = kmac_custom_str;
            custom_len = sizeof(kmac_custom_str);
            if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC128))
                default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
            else
                default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
        } else {
            ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_MAC_TYPE);
            return 0;
        }
        /* If no salt is set then use a default_salt of zeros */
        if (ctx->salt == NULL || ctx->salt_len <= 0) {
            ctx->salt = OPENSSL_zalloc(default_salt_len);
            if (ctx->salt == NULL) {
                ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
                return 0;
            }
            ctx->salt_len = default_salt_len;
        }
        ret = SSKDF_mac_kdm(ctx->macctx,
                            custom, custom_len, ctx->out_len,
                            ctx->salt, ctx->salt_len,
                            ctx->secret, ctx->secret_len,
                            ctx->info, ctx->info_len, key, keylen);
        return ret;
    } else {
        /* H(x) = hash */
        if (md == NULL) {
            ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
            return 0;
        }
        return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
                              ctx->info, ctx->info_len, 0, key, keylen);
    }
}

static int x963kdf_derive(void *vctx, unsigned char *key, size_t keylen,
                          const OSSL_PARAM params[])
{
    KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
    const EVP_MD *md;

    if (!ossl_prov_is_running() || !sskdf_set_ctx_params(ctx, params))
        return 0;

    if (ctx->secret == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
        return 0;
    }

    if (ctx->macctx != NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_NOT_SUPPORTED);
        return 0;
    }

    /* H(x) = hash */
    md = ossl_prov_digest_md(&ctx->digest);
    if (md == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
        return 0;
    }

    return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
                          ctx->info, ctx->info_len, 1, key, keylen);
}

static int sskdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
    const OSSL_PARAM *p;
    KDF_SSKDF *ctx = vctx;
    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
    size_t sz;

    if (params == NULL)
        return 1;

    if (!ossl_prov_macctx_load_from_params(&ctx->macctx, params,
                                           NULL, NULL, NULL, libctx))
        return 0;
   if (ctx->macctx != NULL) {
        if (EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
                         OSSL_MAC_NAME_KMAC128)
            || EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
                            OSSL_MAC_NAME_KMAC256)) {
            ctx->is_kmac = 1;
        }
   }

   if (!ossl_prov_digest_load_from_params(&ctx->digest, params, libctx))
       return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
        || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
        if (!sskdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO)) != NULL)
        if (!sskdf_set_buffer(&ctx->info, &ctx->info_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
        if (!sskdf_set_buffer(&ctx->salt, &ctx->salt_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC_SIZE))
        != NULL) {
        if (!OSSL_PARAM_get_size_t(p, &sz) || sz == 0)
            return 0;
        ctx->out_len = sz;
    }
    return 1;
}

static const OSSL_PARAM *sskdf_settable_ctx_params(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
{
    static const OSSL_PARAM known_settable_ctx_params[] = {
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
        OSSL_PARAM_size_t(OSSL_KDF_PARAM_MAC_SIZE, NULL),
        OSSL_PARAM_END
    };
    return known_settable_ctx_params;
}

static int sskdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
    OSSL_PARAM *p;

    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
        return OSSL_PARAM_set_size_t(p, sskdf_size(ctx));
    return -2;
}

static const OSSL_PARAM *sskdf_gettable_ctx_params(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
{
    static const OSSL_PARAM known_gettable_ctx_params[] = {
        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
        OSSL_PARAM_END
    };
    return known_gettable_ctx_params;
}

const OSSL_DISPATCH ossl_kdf_sskdf_functions[] = {
    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
    { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))sskdf_derive },
    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
      (void(*)(void))sskdf_settable_ctx_params },
    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
      (void(*)(void))sskdf_gettable_ctx_params },
    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
    { 0, NULL }
};

const OSSL_DISPATCH ossl_kdf_x963_kdf_functions[] = {
    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
    { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x963kdf_derive },
    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
      (void(*)(void))sskdf_settable_ctx_params },
    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
      (void(*)(void))sskdf_gettable_ctx_params },
    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
    { 0, NULL }
};

Coverage Report

Created: 2025-06-13 06:58

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
4		*
5		* Licensed under the Apache License 2.0 (the "License"). You may not use
6		* this file except in compliance with the License. You can obtain a copy
7		* in the file LICENSE in the source distribution or at
8		* https://www.openssl.org/source/license.html
9		*/
10
11		/*
12		* Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
13		* Section 4.1.
14		*
15		* The Single Step KDF algorithm is given by:
16		*
17		* Result(0) = empty bit string (i.e., the null string).
18		* For i = 1 to reps, do the following:
19		* Increment counter by 1.
20		* Result(i) = Result(i - 1) \|\| H(counter \|\| Z \|\| FixedInfo).
21		* DKM = LeftmostBits(Result(reps), L))
22		*
23		* NOTES:
24		* Z is a shared secret required to produce the derived key material.
25		* counter is a 4 byte buffer.
26		* FixedInfo is a bit string containing context specific data.
27		* DKM is the output derived key material.
28		* L is the required size of the DKM.
29		* reps = [L / H_outputBits]
30		* H(x) is the auxiliary function that can be either a hash, HMAC or KMAC.
31		* H_outputBits is the length of the output of the auxiliary function H(x).
32		*
33		* Currently there is not a comprehensive list of test vectors for this
34		* algorithm, especially for H(x) = HMAC and H(x) = KMAC.
35		* Test vectors for H(x) = Hash are indirectly used by CAVS KAS tests.
36		*/
37		#include <stdlib.h>
38		#include <stdarg.h>
39		#include <string.h>
40		#include <openssl/hmac.h>
41		#include <openssl/evp.h>
42		#include <openssl/kdf.h>
43		#include <openssl/core_names.h>
44		#include <openssl/params.h>
45		#include <openssl/proverr.h>
46		#include "internal/cryptlib.h"
47		#include "internal/numbers.h"
48		#include "crypto/evp.h"
49		#include "prov/provider_ctx.h"
50		#include "prov/providercommon.h"
51		#include "prov/implementations.h"
52		#include "prov/provider_util.h"
53
54		typedef struct {
55		void *provctx;
56		EVP_MAC_CTX macctx; / H(x) = HMAC_hash OR H(x) = KMAC */
57		PROV_DIGEST digest; /* H(x) = hash(x) */
58		unsigned char *secret;
59		size_t secret_len;
60		unsigned char *info;
61		size_t info_len;
62		unsigned char *salt;
63		size_t salt_len;
64		size_t out_len; /* optional KMAC parameter */
65		int is_kmac;
66		} KDF_SSKDF;
67
68	132	#define SSKDF_MAX_INLEN (1<<30)
69	7	#define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
70	8	#define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
71
72		/* KMAC uses a Customisation string of 'KDF' */
73		static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };
74
75		static OSSL_FUNC_kdf_newctx_fn sskdf_new;
76		static OSSL_FUNC_kdf_freectx_fn sskdf_free;
77		static OSSL_FUNC_kdf_reset_fn sskdf_reset;
78		static OSSL_FUNC_kdf_derive_fn sskdf_derive;
79		static OSSL_FUNC_kdf_derive_fn x963kdf_derive;
80		static OSSL_FUNC_kdf_settable_ctx_params_fn sskdf_settable_ctx_params;
81		static OSSL_FUNC_kdf_set_ctx_params_fn sskdf_set_ctx_params;
82		static OSSL_FUNC_kdf_gettable_ctx_params_fn sskdf_gettable_ctx_params;
83		static OSSL_FUNC_kdf_get_ctx_params_fn sskdf_get_ctx_params;
84
85		/*
86		* Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
87		* Section 4. One-Step Key Derivation using H(x) = hash(x)
88		* Note: X9.63 also uses this code with the only difference being that the
89		* counter is appended to the secret 'z'.
90		* i.e.
91		* result[i] = Hash(counter \|\| z \|\| info) for One Step OR
92		* result[i] = Hash(z \|\| counter \|\| info) for X9.63.
93		*/
94		static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
95		const unsigned char *z, size_t z_len,
96		const unsigned char *info, size_t info_len,
97		unsigned int append_ctr,
98		unsigned char *derived_key, size_t derived_key_len)
99	0	{
100	0	int ret = 0, hlen;
101	0	size_t counter, out_len, len = derived_key_len;
102	0	unsigned char c[4];
103	0	unsigned char mac[EVP_MAX_MD_SIZE];
104	0	unsigned char *out = derived_key;
105	0	EVP_MD_CTX ctx = NULL, ctx_init = NULL;
106
107	0	if (z_len > SSKDF_MAX_INLEN \|\| info_len > SSKDF_MAX_INLEN
108	0	\|\| derived_key_len > SSKDF_MAX_INLEN
109	0	\|\| derived_key_len == 0)
110	0	return 0;
111
112	0	hlen = EVP_MD_get_size(kdf_md);
113	0	if (hlen <= 0)
114	0	return 0;
115	0	out_len = (size_t)hlen;
116
117	0	ctx = EVP_MD_CTX_create();
118	0	ctx_init = EVP_MD_CTX_create();
119	0	if (ctx == NULL \|\| ctx_init == NULL)
120	0	goto end;
121
122	0	if (!EVP_DigestInit(ctx_init, kdf_md))
123	0	goto end;
124
125	0	for (counter = 1;; counter++) {
126	0	c[0] = (unsigned char)((counter >> 24) & 0xff);
127	0	c[1] = (unsigned char)((counter >> 16) & 0xff);
128	0	c[2] = (unsigned char)((counter >> 8) & 0xff);
129	0	c[3] = (unsigned char)(counter & 0xff);
130
131	0	if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
132	0	&& (append_ctr \|\| EVP_DigestUpdate(ctx, c, sizeof(c)))
133	0	&& EVP_DigestUpdate(ctx, z, z_len)
134	0	&& (!append_ctr \|\| EVP_DigestUpdate(ctx, c, sizeof(c)))
135	0	&& EVP_DigestUpdate(ctx, info, info_len)))
136	0	goto end;
137	0	if (len >= out_len) {
138	0	if (!EVP_DigestFinal_ex(ctx, out, NULL))
139	0	goto end;
140	0	out += out_len;
141	0	len -= out_len;
142	0	if (len == 0)
143	0	break;
144	0	} else {
145	0	if (!EVP_DigestFinal_ex(ctx, mac, NULL))
146	0	goto end;
147	0	memcpy(out, mac, len);
148	0	break;
149	0	}
150	0	}
151	0	ret = 1;
152	0	end:
153	0	EVP_MD_CTX_destroy(ctx);
154	0	EVP_MD_CTX_destroy(ctx_init);
155	0	OPENSSL_cleanse(mac, sizeof(mac));
156	0	return ret;
157	0	}
158
159		static int kmac_init(EVP_MAC_CTX ctx, const unsigned char custom,
160		size_t custom_len, size_t kmac_out_len,
161		size_t derived_key_len, unsigned char **out)
162	22	{
163	22	OSSL_PARAM params[2];
164
165		/* Only KMAC has custom data - so return if not KMAC */
166	22	if (custom == NULL)
167	7	return 1;
168
169	15	params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
170	15	(void *)custom, custom_len);
171	15	params[1] = OSSL_PARAM_construct_end();
172
173	15	if (!EVP_MAC_CTX_set_params(ctx, params))
174	0	return 0;
175
176		/* By default only do one iteration if kmac_out_len is not specified */
177	15	if (kmac_out_len == 0)
178	0	kmac_out_len = derived_key_len;
179		/* otherwise check the size is valid */
180	15	else if (!(kmac_out_len == derived_key_len
181	15	\|\| kmac_out_len == 20
182	15	\|\| kmac_out_len == 28
183	15	\|\| kmac_out_len == 32
184	15	\|\| kmac_out_len == 48
185	15	\|\| kmac_out_len == 64))
186	9	return 0;
187
188	6	params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE,
189	6	&kmac_out_len);
190
191	6	if (EVP_MAC_CTX_set_params(ctx, params) <= 0)
192	0	return 0;
193
194		/*
195		* For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
196		* alloc a buffer for this case.
197		*/
198	6	if (kmac_out_len > EVP_MAX_MD_SIZE) {
199	0	*out = OPENSSL_zalloc(kmac_out_len);
200	0	if (*out == NULL)
201	0	return 0;
202	0	}
203	6	return 1;
204	6	}
205
206		/*
207		* Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
208		* Section 4. One-Step Key Derivation using MAC: i.e either
209		* H(x) = HMAC-hash(salt, x) OR
210		* H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
211		*/
212		static int SSKDF_mac_kdm(EVP_MAC_CTX *ctx_init,
213		const unsigned char *kmac_custom,
214		size_t kmac_custom_len, size_t kmac_out_len,
215		const unsigned char *salt, size_t salt_len,
216		const unsigned char *z, size_t z_len,
217		const unsigned char *info, size_t info_len,
218		unsigned char *derived_key, size_t derived_key_len)
219	22	{
220	22	int ret = 0;
221	22	size_t counter, out_len, len;
222	22	unsigned char c[4];
223	22	unsigned char mac_buf[EVP_MAX_MD_SIZE];
224	22	unsigned char *out = derived_key;
225	22	EVP_MAC_CTX *ctx = NULL;
226	22	unsigned char mac = mac_buf, kmac_buffer = NULL;
227
228	22	if (z_len > SSKDF_MAX_INLEN \|\| info_len > SSKDF_MAX_INLEN
229	22	\|\| derived_key_len > SSKDF_MAX_INLEN
230	22	\|\| derived_key_len == 0)
231	0	return 0;
232
233	22	if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
234	22	derived_key_len, &kmac_buffer))
235	9	goto end;
236	13	if (kmac_buffer != NULL)
237	0	mac = kmac_buffer;
238
239	13	if (!EVP_MAC_init(ctx_init, salt, salt_len, NULL))
240	1	goto end;
241
242	12	out_len = EVP_MAC_CTX_get_mac_size(ctx_init); /* output size */
243	12	if (out_len <= 0 \|\| (mac == mac_buf && out_len > sizeof(mac_buf)))
244	0	goto end;
245	12	len = derived_key_len;
246
247	20	for (counter = 1;; counter++) {
248	20	c[0] = (unsigned char)((counter >> 24) & 0xff);
249	20	c[1] = (unsigned char)((counter >> 16) & 0xff);
250	20	c[2] = (unsigned char)((counter >> 8) & 0xff);
251	20	c[3] = (unsigned char)(counter & 0xff);
252
253	20	ctx = EVP_MAC_CTX_dup(ctx_init);
254	20	if (!(ctx != NULL
255	20	&& EVP_MAC_update(ctx, c, sizeof(c))
256	20	&& EVP_MAC_update(ctx, z, z_len)
257	20	&& EVP_MAC_update(ctx, info, info_len)))
258	0	goto end;
259	20	if (len >= out_len) {
260	9	if (!EVP_MAC_final(ctx, out, NULL, len))
261	0	goto end;
262	9	out += out_len;
263	9	len -= out_len;
264	9	if (len == 0)
265	1	break;
266	11	} else {
267	11	if (!EVP_MAC_final(ctx, mac, NULL, out_len))
268	0	goto end;
269	11	memcpy(out, mac, len);
270	11	break;
271	11	}
272	8	EVP_MAC_CTX_free(ctx);
273	8	ctx = NULL;
274	8	}
275	12	ret = 1;
276	22	end:
277	22	if (kmac_buffer != NULL)
278	0	OPENSSL_clear_free(kmac_buffer, kmac_out_len);
279	22	else
280	22	OPENSSL_cleanse(mac_buf, sizeof(mac_buf));
281
282	22	EVP_MAC_CTX_free(ctx);
283	22	return ret;
284	12	}
285
286		static void sskdf_new(void provctx)
287		{
288		KDF_SSKDF *ctx;
289
290		if (!ossl_prov_is_running())
291		return NULL;
292
293		if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
294		ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
295		ctx->provctx = provctx;
296		return ctx;
297		}
298
299		static void sskdf_reset(void *vctx)
300	46	{
301	46	KDF_SSKDF ctx = (KDF_SSKDF )vctx;
302	46	void *provctx = ctx->provctx;
303
304	46	EVP_MAC_CTX_free(ctx->macctx);
305	46	ossl_prov_digest_reset(&ctx->digest);
306	46	OPENSSL_clear_free(ctx->secret, ctx->secret_len);
307	46	OPENSSL_clear_free(ctx->info, ctx->info_len);
308	46	OPENSSL_clear_free(ctx->salt, ctx->salt_len);
309	46	memset(ctx, 0, sizeof(*ctx));
310	46	ctx->provctx = provctx;
311	46	}
312
313		static void sskdf_free(void *vctx)
314	46	{
315	46	KDF_SSKDF ctx = (KDF_SSKDF )vctx;
316
317	46	if (ctx != NULL) {
318	46	sskdf_reset(ctx);
319	46	OPENSSL_free(ctx);
320	46	}
321	46	}
322
323		static int sskdf_set_buffer(unsigned char *out, size_t out_len,
324		const OSSL_PARAM *p)
325	0	{
326	0	if (p->data == NULL \|\| p->data_size == 0)
327	0	return 1;
328	0	OPENSSL_free(*out);
329	0	*out = NULL;
330	0	return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
331	0	}
332
333		static size_t sskdf_size(KDF_SSKDF *ctx)
334	0	{
335	0	int len;
336	0	const EVP_MD *md = NULL;
337
338	0	if (ctx->is_kmac)
339	0	return SIZE_MAX;
340
341	0	md = ossl_prov_digest_md(&ctx->digest);
342	0	if (md == NULL) {
343	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
344	0	return 0;
345	0	}
346	0	len = EVP_MD_get_size(md);
347	0	return (len <= 0) ? 0 : (size_t)len;
348	0	}
349
350		static int sskdf_derive(void vctx, unsigned char key, size_t keylen,
351		const OSSL_PARAM params[])
352	25	{
353	25	KDF_SSKDF ctx = (KDF_SSKDF )vctx;
354	25	const EVP_MD *md;
355
356	25	if (!ossl_prov_is_running() \|\| !sskdf_set_ctx_params(ctx, params))
357	0	return 0;
358	25	if (ctx->secret == NULL) {
359	1	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
360	1	return 0;
361	1	}
362	24	md = ossl_prov_digest_md(&ctx->digest);
363
364	24	if (ctx->macctx != NULL) {
365		/* H(x) = KMAC or H(x) = HMAC */
366	24	int ret;
367	24	const unsigned char *custom = NULL;
368	24	size_t custom_len = 0;
369	24	int default_salt_len;
370	24	EVP_MAC *mac = EVP_MAC_CTX_get0_mac(ctx->macctx);
371
372	24	if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_HMAC)) {
373		/* H(x) = HMAC(x, salt, hash) */
374	8	if (md == NULL) {
375	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
376	0	return 0;
377	0	}
378	8	default_salt_len = EVP_MD_get_size(md);
379	8	if (default_salt_len <= 0)
380	1	return 0;
381	16	} else if (ctx->is_kmac) {
382		/* H(x) = KMACzzz(x, salt, custom) */
383	15	custom = kmac_custom_str;
384	15	custom_len = sizeof(kmac_custom_str);
385	15	if (EVP_MAC_is_a(mac, OSSL_MAC_NAME_KMAC128))
386	7	default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
387	8	else
388	8	default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
389	15	} else {
390	1	ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_MAC_TYPE);
391	1	return 0;
392	1	}
393		/* If no salt is set then use a default_salt of zeros */
394	22	if (ctx->salt == NULL \|\| ctx->salt_len <= 0) {
395	15	ctx->salt = OPENSSL_zalloc(default_salt_len);
396	15	if (ctx->salt == NULL) {
397	0	ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
398	0	return 0;
399	0	}
400	15	ctx->salt_len = default_salt_len;
401	15	}
402	22	ret = SSKDF_mac_kdm(ctx->macctx,
403	22	custom, custom_len, ctx->out_len,
404	22	ctx->salt, ctx->salt_len,
405	22	ctx->secret, ctx->secret_len,
406	22	ctx->info, ctx->info_len, key, keylen);
407	22	return ret;
408	22	} else {
409		/* H(x) = hash */
410	0	if (md == NULL) {
411	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
412	0	return 0;
413	0	}
414	0	return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
415	0	ctx->info, ctx->info_len, 0, key, keylen);
416	0	}
417	24	}
418
419		static int x963kdf_derive(void vctx, unsigned char key, size_t keylen,
420		const OSSL_PARAM params[])
421	2	{
422	2	KDF_SSKDF ctx = (KDF_SSKDF )vctx;
423	2	const EVP_MD *md;
424
425	2	if (!ossl_prov_is_running() \|\| !sskdf_set_ctx_params(ctx, params))
426	0	return 0;
427
428	2	if (ctx->secret == NULL) {
429	1	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
430	1	return 0;
431	1	}
432
433	1	if (ctx->macctx != NULL) {
434	1	ERR_raise(ERR_LIB_PROV, PROV_R_NOT_SUPPORTED);
435	1	return 0;
436	1	}
437
438		/* H(x) = hash */
439	0	md = ossl_prov_digest_md(&ctx->digest);
440	0	if (md == NULL) {
441	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
442	0	return 0;
443	0	}
444
445	0	return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
446	0	ctx->info, ctx->info_len, 1, key, keylen);
447	0	}
448
449		static int sskdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
450	0	{
451	0	const OSSL_PARAM *p;
452	0	KDF_SSKDF *ctx = vctx;
453	0	OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
454	0	size_t sz;
455
456	0	if (params == NULL)
457	0	return 1;
458
459	0	if (!ossl_prov_macctx_load_from_params(&ctx->macctx, params,
460	0	NULL, NULL, NULL, libctx))
461	0	return 0;
462	0	if (ctx->macctx != NULL) {
463	0	if (EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
464	0	OSSL_MAC_NAME_KMAC128)
465	0	\|\| EVP_MAC_is_a(EVP_MAC_CTX_get0_mac(ctx->macctx),
466	0	OSSL_MAC_NAME_KMAC256)) {
467	0	ctx->is_kmac = 1;
468	0	}
469	0	}
470
471	0	if (!ossl_prov_digest_load_from_params(&ctx->digest, params, libctx))
472	0	return 0;
473
474	0	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
475	0	\|\| (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
476	0	if (!sskdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
477	0	return 0;
478
479	0	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO)) != NULL)
480	0	if (!sskdf_set_buffer(&ctx->info, &ctx->info_len, p))
481	0	return 0;
482
483	0	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
484	0	if (!sskdf_set_buffer(&ctx->salt, &ctx->salt_len, p))
485	0	return 0;
486
487	0	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC_SIZE))
488	0	!= NULL) {
489	0	if (!OSSL_PARAM_get_size_t(p, &sz) \|\| sz == 0)
490	0	return 0;
491	0	ctx->out_len = sz;
492	0	}
493	0	return 1;
494	0	}
495
496		static const OSSL_PARAM sskdf_settable_ctx_params(ossl_unused void ctx,
497		ossl_unused void *provctx)
498	36	{
499	36	static const OSSL_PARAM known_settable_ctx_params[] = {
500	36	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
501	36	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
502	36	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
503	36	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
504	36	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
505	36	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
506	36	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
507	36	OSSL_PARAM_size_t(OSSL_KDF_PARAM_MAC_SIZE, NULL),
508	36	OSSL_PARAM_END
509	36	};
510	36	return known_settable_ctx_params;
511	36	}
512
513		static int sskdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
514	0	{
515	0	KDF_SSKDF ctx = (KDF_SSKDF )vctx;
516	0	OSSL_PARAM *p;
517
518	0	if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
519	0	return OSSL_PARAM_set_size_t(p, sskdf_size(ctx));
520	0	return -2;
521	0	}
522
523		static const OSSL_PARAM sskdf_gettable_ctx_params(ossl_unused void ctx,
524		ossl_unused void *provctx)
525	0	{
526	0	static const OSSL_PARAM known_gettable_ctx_params[] = {
527	0	OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
528	0	OSSL_PARAM_END
529	0	};
530	0	return known_gettable_ctx_params;
531	0	}
532
533		const OSSL_DISPATCH ossl_kdf_sskdf_functions[] = {
534		{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
535		{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
536		{ OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
537		{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))sskdf_derive },
538		{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
539		(void(*)(void))sskdf_settable_ctx_params },
540		{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
541		{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
542		(void(*)(void))sskdf_gettable_ctx_params },
543		{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
544		{ 0, NULL }
545		};
546
547		const OSSL_DISPATCH ossl_kdf_x963_kdf_functions[] = {
548		{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
549		{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
550		{ OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
551		{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))x963kdf_derive },
552		{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
553		(void(*)(void))sskdf_settable_ctx_params },
554		{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
555		{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
556		(void(*)(void))sskdf_gettable_ctx_params },
557		{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
558		{ 0, NULL }
559		};