[thirdparty/openssl.git] / crypto / kdf / sskdf.c

/*
 * Copyright 2019 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 "internal/cryptlib.h"
#include "internal/evp_int.h"
#include "kdf_local.h"

struct evp_kdf_impl_st {
    const EVP_MAC *mac; /* H(x) = HMAC_hash OR H(x) = KMAC */
    const EVP_MD *md;   /* H(x) = hash OR when H(x) = HMAC_hash */
    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 */
};

#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 };

/*
 * 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)
 */
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 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_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)
                && EVP_DigestUpdate(ctx, c, sizeof(c))
                && EVP_DigestUpdate(ctx, z, z_len)
                && 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)
{
    /* Only KMAC has custom data - so return if not KMAC */
    if (custom == NULL)
        return 1;

    if (EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_CUSTOM, custom, custom_len) <= 0)
        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;

    if (EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_SIZE, kmac_out_len) <= 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(const EVP_MAC *kdf_mac, const EVP_MD *hmac_md,
                         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, *ctx_init = 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;

    ctx = EVP_MAC_CTX_new(kdf_mac);
    ctx_init = EVP_MAC_CTX_new(kdf_mac);
    if (ctx == NULL || ctx_init == NULL)
        goto end;
    if (hmac_md != NULL &&
            EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_MD, hmac_md) <= 0)
        goto end;

    if (EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_KEY, salt, salt_len) <= 0)
        goto end;

    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))
        goto end;

    out_len = EVP_MAC_size(ctx_init); /* output size */
    if (out_len <= 0)
        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);

        if (!(EVP_MAC_CTX_copy(ctx, ctx_init)
                && 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))
                goto end;
            out += out_len;
            len -= out_len;
            if (len == 0)
                break;
        } else {
            if (!EVP_MAC_final(ctx, mac, NULL))
                goto end;
            memcpy(out, mac, len);
            break;
        }
    }
    ret = 1;
end:
    OPENSSL_free(kmac_buffer);
    EVP_MAC_CTX_free(ctx);
    EVP_MAC_CTX_free(ctx_init);
    OPENSSL_cleanse(mac, sizeof(mac));
    return ret;
}

static EVP_KDF_IMPL *sskdf_new(void)
{
    EVP_KDF_IMPL *impl;

    if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
        KDFerr(KDF_F_SSKDF_NEW, ERR_R_MALLOC_FAILURE);
    return impl;
}

static void sskdf_reset(EVP_KDF_IMPL *impl)
{
    OPENSSL_clear_free(impl->secret, impl->secret_len);
    OPENSSL_clear_free(impl->info, impl->info_len);
    OPENSSL_clear_free(impl->salt, impl->salt_len);
    memset(impl, 0, sizeof(*impl));
}

static void sskdf_free(EVP_KDF_IMPL *impl)
{
    sskdf_reset(impl);
    OPENSSL_free(impl);
}

static int sskdf_set_buffer(va_list args, unsigned char **out, size_t *out_len)
{
    const unsigned char *p;
    size_t len;

    p = va_arg(args, const unsigned char *);
    len = va_arg(args, size_t);
    if (len == 0 || p == NULL)
        return 1;

    OPENSSL_free(*out);
    *out = OPENSSL_memdup(p, len);
    if (*out == NULL)
        return 0;

    *out_len = len;
    return 1;
}

static int sskdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
{
    const EVP_MD *md;
    const EVP_MAC *mac;

    switch (cmd) {
    case EVP_KDF_CTRL_SET_KEY:
        return sskdf_set_buffer(args, &impl->secret, &impl->secret_len);

    case EVP_KDF_CTRL_SET_SSKDF_INFO:
        return sskdf_set_buffer(args, &impl->info, &impl->info_len);

    case EVP_KDF_CTRL_SET_MD:
        md = va_arg(args, const EVP_MD *);
        if (md == NULL)
            return 0;

        impl->md = md;
        return 1;

    case EVP_KDF_CTRL_SET_MAC:
        mac = va_arg(args, const EVP_MAC *);
        if (mac == NULL)
            return 0;

        impl->mac = mac;
        return 1;

    case EVP_KDF_CTRL_SET_SALT:
        return sskdf_set_buffer(args, &impl->salt, &impl->salt_len);

    case EVP_KDF_CTRL_SET_MAC_SIZE:
        impl->out_len = va_arg(args, size_t);
        return 1;

    default:
        return -2;
    }
}

/* Pass a mac to a ctrl */
static int sskdf_mac2ctrl(EVP_KDF_IMPL *impl,
                          int (*ctrl)(EVP_KDF_IMPL *impl, int cmd, va_list args),
                          int cmd, const char *mac_name)
{
    const EVP_MAC *mac;

    if (mac_name == NULL || (mac = EVP_get_macbyname(mac_name)) == NULL) {
        KDFerr(KDF_F_SSKDF_MAC2CTRL, KDF_R_INVALID_MAC_TYPE);
        return 0;
    }
    return call_ctrl(ctrl, impl, cmd, mac);
}

static int sskdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
                          const char *value)
{
    if (strcmp(type, "secret") == 0 || strcmp(type, "key") == 0)
         return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
                             value);

    if (strcmp(type, "hexsecret") == 0 || strcmp(type, "hexkey") == 0)
        return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
                            value);

    if (strcmp(type, "info") == 0)
        return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
                            value);

    if (strcmp(type, "hexinfo") == 0)
        return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
                            value);

    if (strcmp(type, "digest") == 0)
        return kdf_md2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MD, value);

    if (strcmp(type, "mac") == 0)
        return sskdf_mac2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MAC, value);

    if (strcmp(type, "salt") == 0)
        return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);

    if (strcmp(type, "hexsalt") == 0)
        return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);


    if (strcmp(type, "maclen") == 0) {
        int val = atoi(value);
        if (val < 0) {
            KDFerr(KDF_F_SSKDF_CTRL_STR, KDF_R_VALUE_ERROR);
            return 0;
        }
        return call_ctrl(sskdf_ctrl, impl, EVP_KDF_CTRL_SET_MAC_SIZE,
                         (size_t)val);
    }
    return -2;
}

static size_t sskdf_size(EVP_KDF_IMPL *impl)
{
    int len;

    if (impl->md == NULL) {
        KDFerr(KDF_F_SSKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
        return 0;
    }
    len = EVP_MD_size(impl->md);
    return (len <= 0) ? 0 : (size_t)len;
}

static int sskdf_derive(EVP_KDF_IMPL *impl, unsigned char *key, size_t keylen)
{
    if (impl->secret == NULL) {
        KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_SECRET);
        return 0;
    }

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

        nid = EVP_MAC_nid(impl->mac);
        if (nid == EVP_MAC_HMAC) {
            /* H(x) = HMAC(x, salt, hash) */
            if (impl->md == NULL) {
                KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
                return 0;
            }
            default_salt_len = EVP_MD_block_size(impl->md);
            if (default_salt_len <= 0)
                return 0;
        } else if (nid == EVP_MAC_KMAC128 || nid == EVP_MAC_KMAC256) {
            /* H(x) = KMACzzz(x, salt, custom) */
            custom = kmac_custom_str;
            custom_len = sizeof(kmac_custom_str);
            if (nid == EVP_MAC_KMAC128)
                default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
            else
                default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
        } else {
            KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_UNSUPPORTED_MAC_TYPE);
            return 0;
        }
        /* If no salt is set then use a default_salt of zeros */
        if (impl->salt == NULL || impl->salt_len <= 0) {
            impl->salt = OPENSSL_zalloc(default_salt_len);
            if (impl->salt == NULL) {
                KDFerr(KDF_F_SSKDF_DERIVE, ERR_R_MALLOC_FAILURE);
                return 0;
            }
            impl->salt_len = default_salt_len;
        }
        ret = SSKDF_mac_kdm(impl->mac, impl->md,
                            custom, custom_len, impl->out_len,
                            impl->salt, impl->salt_len,
                            impl->secret, impl->secret_len,
                            impl->info, impl->info_len, key, keylen);
        return ret;
    } else {
        /* H(x) = hash */
        if (impl->md == NULL) {
            KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
            return 0;
        }
        return SSKDF_hash_kdm(impl->md, impl->secret, impl->secret_len,
                              impl->info, impl->info_len, key, keylen);
    }
}

const EVP_KDF_METHOD ss_kdf_meth = {
    EVP_KDF_SS,
    sskdf_new,
    sskdf_free,
    sskdf_reset,
    sskdf_ctrl,
    sskdf_ctrl_str,
    sskdf_size,
    sskdf_derive
};
Commit	Line	Data
9537fe57 SL	1	/*
	2	* Copyright 2019 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 "internal/cryptlib.h"
	44	#include "internal/evp_int.h"
	45	#include "kdf_local.h"
	46
	47	struct evp_kdf_impl_st {
	48	const EVP_MAC mac; / H(x) = HMAC_hash OR H(x) = KMAC */
	49	const EVP_MD md; / H(x) = hash OR when H(x) = HMAC_hash */
	50	unsigned char *secret;
	51	size_t secret_len;
	52	unsigned char *info;
	53	size_t info_len;
	54	unsigned char *salt;
	55	size_t salt_len;
	56	size_t out_len; /* optional KMAC parameter */
	57	};
	58
	59	#define SSKDF_MAX_INLEN (1<<30)
	60	#define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
	61	#define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
	62
	63	/* KMAC uses a Customisation string of 'KDF' */
	64	static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };
65
66	/*
67	* Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
68	* Section 4. One-Step Key Derivation using H(x) = hash(x)
69	*/
70	static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
71	const unsigned char *z, size_t z_len,
72	const unsigned char *info, size_t info_len,
73	unsigned char *derived_key, size_t derived_key_len)
74	{
75	int ret = 0, hlen;
76	size_t counter, out_len, len = derived_key_len;
77	unsigned char c[4];
78	unsigned char mac[EVP_MAX_MD_SIZE];
79	unsigned char *out = derived_key;
80	EVP_MD_CTX ctx = NULL, ctx_init = NULL;
81
82	if (z_len > SSKDF_MAX_INLEN \|\| info_len > SSKDF_MAX_INLEN
83	\|\| derived_key_len > SSKDF_MAX_INLEN
84	\|\| derived_key_len == 0)
85	return 0;
86
87	hlen = EVP_MD_size(kdf_md);
88	if (hlen <= 0)
89	return 0;
90	out_len = (size_t)hlen;
91
92	ctx = EVP_MD_CTX_create();
93	ctx_init = EVP_MD_CTX_create();
94	if (ctx == NULL \|\| ctx_init == NULL)
95	goto end;
96
97	if (!EVP_DigestInit(ctx_init, kdf_md))
98	goto end;
99
100	for (counter = 1;; counter++) {
101	c[0] = (unsigned char)((counter >> 24) & 0xff);
102	c[1] = (unsigned char)((counter >> 16) & 0xff);
103	c[2] = (unsigned char)((counter >> 8) & 0xff);
104	c[3] = (unsigned char)(counter & 0xff);
105
106	if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
107	&& EVP_DigestUpdate(ctx, c, sizeof(c))
108	&& EVP_DigestUpdate(ctx, z, z_len)
109	&& EVP_DigestUpdate(ctx, info, info_len)))
110	goto end;
111	if (len >= out_len) {
112	if (!EVP_DigestFinal_ex(ctx, out, NULL))
113	goto end;
114	out += out_len;
115	len -= out_len;
116	if (len == 0)
117	break;
118	} else {
119	if (!EVP_DigestFinal_ex(ctx, mac, NULL))
120	goto end;
121	memcpy(out, mac, len);
122	break;
123	}
124	}
125	ret = 1;
126	end:
127	EVP_MD_CTX_destroy(ctx);
128	EVP_MD_CTX_destroy(ctx_init);
129	OPENSSL_cleanse(mac, sizeof(mac));
130	return ret;
131	}
132
133	static int kmac_init(EVP_MAC_CTX ctx, const unsigned char custom,
134	size_t custom_len, size_t kmac_out_len,
135	size_t derived_key_len, unsigned char **out)
136	{
137	/* Only KMAC has custom data - so return if not KMAC */
138	if (custom == NULL)
139	return 1;
140
17838470	141	if (EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_CUSTOM, custom, custom_len) <= 0)
9537fe57 SL	142	return 0;
	143
	144	/* By default only do one iteration if kmac_out_len is not specified */
	145	if (kmac_out_len == 0)
	146	kmac_out_len = derived_key_len;
	147	/* otherwise check the size is valid */
	148	else if (!(kmac_out_len == derived_key_len
	149	\|\| kmac_out_len == 20
	150	\|\| kmac_out_len == 28
	151	\|\| kmac_out_len == 32
	152	\|\| kmac_out_len == 48
	153	\|\| kmac_out_len == 64))
	154	return 0;
	155
17838470	156	if (EVP_MAC_ctrl(ctx, EVP_MAC_CTRL_SET_SIZE, kmac_out_len) <= 0)
9537fe57 SL	157	return 0;
	158
	159	/*
	160	* For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
	161	* alloc a buffer for this case.
	162	*/
	163	if (kmac_out_len > EVP_MAX_MD_SIZE) {
	164	*out = OPENSSL_zalloc(kmac_out_len);
	165	if (*out == NULL)
	166	return 0;
	167	}
	168	return 1;
	169	}
	170
	171	/*
	172	* Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
	173	* Section 4. One-Step Key Derivation using MAC: i.e either
	174	* H(x) = HMAC-hash(salt, x) OR
	175	* H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
	176	*/
	177	static int SSKDF_mac_kdm(const EVP_MAC kdf_mac, const EVP_MD hmac_md,
	178	const unsigned char *kmac_custom,
	179	size_t kmac_custom_len, size_t kmac_out_len,
	180	const unsigned char *salt, size_t salt_len,
	181	const unsigned char *z, size_t z_len,
	182	const unsigned char *info, size_t info_len,
	183	unsigned char *derived_key, size_t derived_key_len)
	184	{
	185	int ret = 0;
	186	size_t counter, out_len, len;
	187	unsigned char c[4];
	188	unsigned char mac_buf[EVP_MAX_MD_SIZE];
	189	unsigned char *out = derived_key;
	190	EVP_MAC_CTX ctx = NULL, ctx_init = NULL;
	191	unsigned char mac = mac_buf, kmac_buffer = NULL;
	192
	193	if (z_len > SSKDF_MAX_INLEN \|\| info_len > SSKDF_MAX_INLEN
	194	\|\| derived_key_len > SSKDF_MAX_INLEN
	195	\|\| derived_key_len == 0)
	196	return 0;
	197
	198	ctx = EVP_MAC_CTX_new(kdf_mac);
	199	ctx_init = EVP_MAC_CTX_new(kdf_mac);
	200	if (ctx == NULL \|\| ctx_init == NULL)
	201	goto end;
	202	if (hmac_md != NULL &&
17838470	203	EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_MD, hmac_md) <= 0)
9537fe57 SL	204	goto end;
9537fe57 SL	205
17838470	206	if (EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_KEY, salt, salt_len) <= 0)
9537fe57 SL	207	goto end;
	208
	209	if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
	210	derived_key_len, &kmac_buffer))
	211	goto end;
	212	if (kmac_buffer != NULL)
	213	mac = kmac_buffer;
	214
	215	if (!EVP_MAC_init(ctx_init))
	216	goto end;
	217
	218	out_len = EVP_MAC_size(ctx_init); /* output size */
	219	if (out_len <= 0)
	220	goto end;
	221	len = derived_key_len;
	222
	223	for (counter = 1;; counter++) {
	224	c[0] = (unsigned char)((counter >> 24) & 0xff);
	225	c[1] = (unsigned char)((counter >> 16) & 0xff);
	226	c[2] = (unsigned char)((counter >> 8) & 0xff);
	227	c[3] = (unsigned char)(counter & 0xff);
	228
	229	if (!(EVP_MAC_CTX_copy(ctx, ctx_init)
	230	&& EVP_MAC_update(ctx, c, sizeof(c))
	231	&& EVP_MAC_update(ctx, z, z_len)
	232	&& EVP_MAC_update(ctx, info, info_len)))
	233	goto end;
	234	if (len >= out_len) {
	235	if (!EVP_MAC_final(ctx, out, NULL))
	236	goto end;
	237	out += out_len;
	238	len -= out_len;
	239	if (len == 0)
	240	break;
	241	} else {
	242	if (!EVP_MAC_final(ctx, mac, NULL))
	243	goto end;
	244	memcpy(out, mac, len);
	245	break;
	246	}
	247	}
	248	ret = 1;
	249	end:
	250	OPENSSL_free(kmac_buffer);
	251	EVP_MAC_CTX_free(ctx);
	252	EVP_MAC_CTX_free(ctx_init);
	253	OPENSSL_cleanse(mac, sizeof(mac));
	254	return ret;
	255	}
	256
	257	static EVP_KDF_IMPL *sskdf_new(void)
	258	{
	259	EVP_KDF_IMPL *impl;
	260
	261	if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
	262	KDFerr(KDF_F_SSKDF_NEW, ERR_R_MALLOC_FAILURE);
	263	return impl;
	264	}
	265
	266	static void sskdf_reset(EVP_KDF_IMPL *impl)
	267	{
	268	OPENSSL_clear_free(impl->secret, impl->secret_len);
	269	OPENSSL_clear_free(impl->info, impl->info_len);
	270	OPENSSL_clear_free(impl->salt, impl->salt_len);
271	memset(impl, 0, sizeof(*impl));
272	}
273
274	static void sskdf_free(EVP_KDF_IMPL *impl)
275	{
276	sskdf_reset(impl);
277	OPENSSL_free(impl);
278	}
279
280	static int sskdf_set_buffer(va_list args, unsigned char *out, size_t out_len)
281	{
282	const unsigned char *p;
283	size_t len;
284
285	p = va_arg(args, const unsigned char *);
286	len = va_arg(args, size_t);
287	if (len == 0 \|\| p == NULL)
288	return 1;
289
290	OPENSSL_free(*out);
291	*out = OPENSSL_memdup(p, len);
292	if (*out == NULL)
293	return 0;
294
295	*out_len = len;
296	return 1;
297	}
298
299	static int sskdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
300	{
301	const EVP_MD *md;
302	const EVP_MAC *mac;
303
304	switch (cmd) {
305	case EVP_KDF_CTRL_SET_KEY:
306	return sskdf_set_buffer(args, &impl->secret, &impl->secret_len);
307
308	case EVP_KDF_CTRL_SET_SSKDF_INFO:
309	return sskdf_set_buffer(args, &impl->info, &impl->info_len);
310
311	case EVP_KDF_CTRL_SET_MD:
312	md = va_arg(args, const EVP_MD *);
313	if (md == NULL)
314	return 0;
315
316	impl->md = md;
317	return 1;
318
319	case EVP_KDF_CTRL_SET_MAC:
320	mac = va_arg(args, const EVP_MAC *);
321	if (mac == NULL)
322	return 0;
323
324	impl->mac = mac;
325	return 1;
326
327	case EVP_KDF_CTRL_SET_SALT:
328	return sskdf_set_buffer(args, &impl->salt, &impl->salt_len);
329
330	case EVP_KDF_CTRL_SET_MAC_SIZE:
331	impl->out_len = va_arg(args, size_t);
332	return 1;
333
334	default:
335	return -2;
336	}
337	}
338
339	/* Pass a mac to a ctrl */
340	static int sskdf_mac2ctrl(EVP_KDF_IMPL *impl,
341	int (ctrl)(EVP_KDF_IMPL impl, int cmd, va_list args),
342	int cmd, const char *mac_name)
343	{
344	const EVP_MAC *mac;
345
346	if (mac_name == NULL \|\| (mac = EVP_get_macbyname(mac_name)) == NULL) {
347	KDFerr(KDF_F_SSKDF_MAC2CTRL, KDF_R_INVALID_MAC_TYPE);
348	return 0;
349	}
350	return call_ctrl(ctrl, impl, cmd, mac);
351	}
352
353	static int sskdf_ctrl_str(EVP_KDF_IMPL impl, const char type,
354	const char *value)
355	{
356	if (strcmp(type, "secret") == 0 \|\| strcmp(type, "key") == 0)
357	return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
358	value);
359
360	if (strcmp(type, "hexsecret") == 0 \|\| strcmp(type, "hexkey") == 0)
361	return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_KEY,
362	value);
363
364	if (strcmp(type, "info") == 0)
365	return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
366	value);
367
368	if (strcmp(type, "hexinfo") == 0)
369	return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SSKDF_INFO,
370	value);
371
372	if (strcmp(type, "digest") == 0)
373	return kdf_md2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MD, value);
374
375	if (strcmp(type, "mac") == 0)
376	return sskdf_mac2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_MAC, value);
377
378	if (strcmp(type, "salt") == 0)
379	return kdf_str2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);
380
381	if (strcmp(type, "hexsalt") == 0)
382	return kdf_hex2ctrl(impl, sskdf_ctrl, EVP_KDF_CTRL_SET_SALT, value);
383
384
385	if (strcmp(type, "maclen") == 0) {
386	int val = atoi(value);
387	if (val < 0) {
388	KDFerr(KDF_F_SSKDF_CTRL_STR, KDF_R_VALUE_ERROR);
389	return 0;
390	}
391	return call_ctrl(sskdf_ctrl, impl, EVP_KDF_CTRL_SET_MAC_SIZE,
392	(size_t)val);
393	}
394	return -2;
395	}
396
397	static size_t sskdf_size(EVP_KDF_IMPL *impl)
398	{
399	int len;
400
401	if (impl->md == NULL) {
402	KDFerr(KDF_F_SSKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
403	return 0;
404	}
405	len = EVP_MD_size(impl->md);
406	return (len <= 0) ? 0 : (size_t)len;
407	}
408
409	static int sskdf_derive(EVP_KDF_IMPL impl, unsigned char key, size_t keylen)
410	{
411	if (impl->secret == NULL) {
412	KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_SECRET);
413	return 0;
414	}
415
416	if (impl->mac != NULL) {
417	/* H(x) = KMAC or H(x) = HMAC */
418	int ret;
419	const unsigned char *custom = NULL;
420	size_t custom_len = 0;
421	int nid;
422	int default_salt_len;
423
424	nid = EVP_MAC_nid(impl->mac);
425	if (nid == EVP_MAC_HMAC) {
426	/* H(x) = HMAC(x, salt, hash) */
427	if (impl->md == NULL) {
428	KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
429	return 0;
430	}
431	default_salt_len = EVP_MD_block_size(impl->md);
432	if (default_salt_len <= 0)
433	return 0;
434	} else if (nid == EVP_MAC_KMAC128 \|\| nid == EVP_MAC_KMAC256) {
435	/* H(x) = KMACzzz(x, salt, custom) */
436	custom = kmac_custom_str;
437	custom_len = sizeof(kmac_custom_str);
438	if (nid == EVP_MAC_KMAC128)
439	default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
440	else
441	default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
442	} else {
443	KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_UNSUPPORTED_MAC_TYPE);
444	return 0;
445	}
446	/* If no salt is set then use a default_salt of zeros */
447	if (impl->salt == NULL \|\| impl->salt_len <= 0) {
448	impl->salt = OPENSSL_zalloc(default_salt_len);
449	if (impl->salt == NULL) {
450	KDFerr(KDF_F_SSKDF_DERIVE, ERR_R_MALLOC_FAILURE);
451	return 0;
452	}
453	impl->salt_len = default_salt_len;
454	}
455	ret = SSKDF_mac_kdm(impl->mac, impl->md,
456	custom, custom_len, impl->out_len,
457	impl->salt, impl->salt_len,
458	impl->secret, impl->secret_len,
459	impl->info, impl->info_len, key, keylen);
460	return ret;
461	} else {
462	/* H(x) = hash */
463	if (impl->md == NULL) {
464	KDFerr(KDF_F_SSKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
465	return 0;
466	}
467	return SSKDF_hash_kdm(impl->md, impl->secret, impl->secret_len,
468	impl->info, impl->info_len, key, keylen);
469	}
470	}
471
472	const EVP_KDF_METHOD ss_kdf_meth = {
473	EVP_KDF_SS,
474	sskdf_new,
475	sskdf_free,
476	sskdf_reset,
477	sskdf_ctrl,
478	sskdf_ctrl_str,
479	sskdf_size,
480	sskdf_derive
481	};