[thirdparty/openssl.git] / providers / implementations / kdfs / sshkdf.c

/*
 * Copyright 2018-2023 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
 */

#include <stdlib.h>
#include <stdarg.h>
#include <string.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"

/* See RFC 4253, Section 7.2 */
static OSSL_FUNC_kdf_newctx_fn kdf_sshkdf_new;
static OSSL_FUNC_kdf_dupctx_fn kdf_sshkdf_dup;
static OSSL_FUNC_kdf_freectx_fn kdf_sshkdf_free;
static OSSL_FUNC_kdf_reset_fn kdf_sshkdf_reset;
static OSSL_FUNC_kdf_derive_fn kdf_sshkdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_sshkdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn kdf_sshkdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_sshkdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn kdf_sshkdf_get_ctx_params;

static int SSHKDF(const EVP_MD *evp_md,
                  const unsigned char *key, size_t key_len,
                  const unsigned char *xcghash, size_t xcghash_len,
                  const unsigned char *session_id, size_t session_id_len,
                  char type, unsigned char *okey, size_t okey_len);

typedef struct {
    void *provctx;
    PROV_DIGEST digest;
    unsigned char *key; /* K */
    size_t key_len;
    unsigned char *xcghash; /* H */
    size_t xcghash_len;
    char type; /* X */
    unsigned char *session_id;
    size_t session_id_len;
} KDF_SSHKDF;

static void *kdf_sshkdf_new(void *provctx)
{
    KDF_SSHKDF *ctx;

    if (!ossl_prov_is_running())
        return NULL;

    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL)
        ctx->provctx = provctx;
    return ctx;
}

static void kdf_sshkdf_free(void *vctx)
{
    KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;

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

static void kdf_sshkdf_reset(void *vctx)
{
    KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
    void *provctx = ctx->provctx;

    ossl_prov_digest_reset(&ctx->digest);
    OPENSSL_clear_free(ctx->key, ctx->key_len);
    OPENSSL_clear_free(ctx->xcghash, ctx->xcghash_len);
    OPENSSL_clear_free(ctx->session_id, ctx->session_id_len);
    memset(ctx, 0, sizeof(*ctx));
    ctx->provctx = provctx;
}

static void *kdf_sshkdf_dup(void *vctx)
{
    const KDF_SSHKDF *src = (const KDF_SSHKDF *)vctx;
    KDF_SSHKDF *dest;

    dest = kdf_sshkdf_new(src->provctx);
    if (dest != NULL) {
        if (!ossl_prov_memdup(src->key, src->key_len,
                              &dest->key, &dest->key_len)
                || !ossl_prov_memdup(src->xcghash, src->xcghash_len,
                                     &dest->xcghash , &dest->xcghash_len)
                || !ossl_prov_memdup(src->session_id, src->session_id_len,
                                     &dest->session_id , &dest->session_id_len)
                || !ossl_prov_digest_copy(&dest->digest, &src->digest))
            goto err;
        dest->type = src->type;
    }
    return dest;

 err:
    kdf_sshkdf_free(dest);
    return NULL;
}

static int sshkdf_set_membuf(unsigned char **dst, size_t *dst_len,
                             const OSSL_PARAM *p)
{
    OPENSSL_clear_free(*dst, *dst_len);
    *dst = NULL;
    *dst_len = 0;
    return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
}

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

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

    md = ossl_prov_digest_md(&ctx->digest);
    if (md == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
        return 0;
    }
    if (ctx->key == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
        return 0;
    }
    if (ctx->xcghash == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_XCGHASH);
        return 0;
    }
    if (ctx->session_id == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SESSION_ID);
        return 0;
    }
    if (ctx->type == 0) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_TYPE);
        return 0;
    }
    return SSHKDF(md, ctx->key, ctx->key_len,
                  ctx->xcghash, ctx->xcghash_len,
                  ctx->session_id, ctx->session_id_len,
                  ctx->type, key, keylen);
}

static int kdf_sshkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
    const OSSL_PARAM *p;
    KDF_SSHKDF *ctx = vctx;
    OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);

    if (params == NULL)
        return 1;

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

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
        if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_XCGHASH))
        != NULL)
        if (!sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_SESSION_ID))
        != NULL)
        if (!sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p))
            return 0;

    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_TYPE))
        != NULL) {
        const char *kdftype;

        if (!OSSL_PARAM_get_utf8_string_ptr(p, &kdftype))
            return 0;
        /* Expect one character (byte in this case) */
        if (kdftype == NULL || p->data_size != 1)
            return 0;
        if (kdftype[0] < 65 || kdftype[0] > 70) {
            ERR_raise(ERR_LIB_PROV, PROV_R_VALUE_ERROR);
            return 0;
        }
        ctx->type = kdftype[0];
    }
    return 1;
}

static const OSSL_PARAM *kdf_sshkdf_settable_ctx_params(ossl_unused void *ctx,
                                                        ossl_unused void *p_ctx)
{
    static const OSSL_PARAM known_settable_ctx_params[] = {
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_XCGHASH, NULL, 0),
        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_SESSION_ID, NULL, 0),
        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_SSHKDF_TYPE, NULL, 0),
        OSSL_PARAM_END
    };
    return known_settable_ctx_params;
}

static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    OSSL_PARAM *p;

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

static const OSSL_PARAM *kdf_sshkdf_gettable_ctx_params(ossl_unused void *ctx,
                                                        ossl_unused void *p_ctx)
{
    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_sshkdf_functions[] = {
    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_sshkdf_new },
    { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_sshkdf_dup },
    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_sshkdf_free },
    { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_sshkdf_reset },
    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_sshkdf_derive },
    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
      (void(*)(void))kdf_sshkdf_settable_ctx_params },
    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_set_ctx_params },
    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
      (void(*)(void))kdf_sshkdf_gettable_ctx_params },
    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_get_ctx_params },
    OSSL_DISPATCH_END
};

static int SSHKDF(const EVP_MD *evp_md,
                  const unsigned char *key, size_t key_len,
                  const unsigned char *xcghash, size_t xcghash_len,
                  const unsigned char *session_id, size_t session_id_len,
                  char type, unsigned char *okey, size_t okey_len)
{
    EVP_MD_CTX *md = NULL;
    unsigned char digest[EVP_MAX_MD_SIZE];
    unsigned int dsize = 0;
    size_t cursize = 0;
    int ret = 0;

    md = EVP_MD_CTX_new();
    if (md == NULL)
        return 0;

    if (!EVP_DigestInit_ex(md, evp_md, NULL))
        goto out;

    if (!EVP_DigestUpdate(md, key, key_len))
        goto out;

    if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
        goto out;

    if (!EVP_DigestUpdate(md, &type, 1))
        goto out;

    if (!EVP_DigestUpdate(md, session_id, session_id_len))
        goto out;

    if (!EVP_DigestFinal_ex(md, digest, &dsize))
        goto out;

    if (okey_len < dsize) {
        memcpy(okey, digest, okey_len);
        ret = 1;
        goto out;
    }

    memcpy(okey, digest, dsize);

    for (cursize = dsize; cursize < okey_len; cursize += dsize) {

        if (!EVP_DigestInit_ex(md, evp_md, NULL))
            goto out;

        if (!EVP_DigestUpdate(md, key, key_len))
            goto out;

        if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
            goto out;

        if (!EVP_DigestUpdate(md, okey, cursize))
            goto out;

        if (!EVP_DigestFinal_ex(md, digest, &dsize))
            goto out;

        if (okey_len < cursize + dsize) {
            memcpy(okey + cursize, digest, okey_len - cursize);
            ret = 1;
            goto out;
        }

        memcpy(okey + cursize, digest, dsize);
    }

    ret = 1;

out:
    EVP_MD_CTX_free(md);
    OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);
    return ret;
}
Commit	Line	Data
e3405a4a	1	/*
da1c088f	2	* Copyright 2018-2023 The OpenSSL Project Authors. All Rights Reserved.
e3405a4a	3	*
a6ed19dc	4	* Licensed under the Apache License 2.0 (the "License"). You may not use
e3405a4a P	5	* this file except in compliance with the License. You can obtain a copy
	6	* in the file LICENSE in the source distribution or at
	7	* https://www.openssl.org/source/license.html
	8	*/
	9
	10	#include <stdlib.h>
	11	#include <stdarg.h>
	12	#include <string.h>
	13	#include <openssl/evp.h>
	14	#include <openssl/kdf.h>
	15	#include <openssl/core_names.h>
2741128e	16	#include <openssl/proverr.h>
e3405a4a P	17	#include "internal/cryptlib.h"
e3405a4a P	18	#include "internal/numbers.h"
25f2138b	19	#include "crypto/evp.h"
ddd21319	20	#include "prov/provider_ctx.h"
2b9e4e95	21	#include "prov/providercommon.h"
af3e7e1b	22	#include "prov/implementations.h"
2b9e4e95	23	#include "prov/provider_util.h"
e3405a4a P	24
e3405a4a P	25	/* See RFC 4253, Section 7.2 */
363b1e5d	26	static OSSL_FUNC_kdf_newctx_fn kdf_sshkdf_new;
59558f9d	27	static OSSL_FUNC_kdf_dupctx_fn kdf_sshkdf_dup;
363b1e5d DMSP	28	static OSSL_FUNC_kdf_freectx_fn kdf_sshkdf_free;
	29	static OSSL_FUNC_kdf_reset_fn kdf_sshkdf_reset;
	30	static OSSL_FUNC_kdf_derive_fn kdf_sshkdf_derive;
	31	static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_sshkdf_settable_ctx_params;
	32	static OSSL_FUNC_kdf_set_ctx_params_fn kdf_sshkdf_set_ctx_params;
	33	static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_sshkdf_gettable_ctx_params;
	34	static OSSL_FUNC_kdf_get_ctx_params_fn kdf_sshkdf_get_ctx_params;
e3405a4a P	35
	36	static int SSHKDF(const EVP_MD *evp_md,
	37	const unsigned char *key, size_t key_len,
	38	const unsigned char *xcghash, size_t xcghash_len,
	39	const unsigned char *session_id, size_t session_id_len,
	40	char type, unsigned char *okey, size_t okey_len);
	41
	42	typedef struct {
	43	void *provctx;
a1de4680	44	PROV_DIGEST digest;
e3405a4a P	45	unsigned char key; / K */
	46	size_t key_len;
	47	unsigned char xcghash; / H */
	48	size_t xcghash_len;
	49	char type; /* X */
	50	unsigned char *session_id;
	51	size_t session_id_len;
	52	} KDF_SSHKDF;
	53
	54	static void kdf_sshkdf_new(void provctx)
	55	{
	56	KDF_SSHKDF *ctx;
	57
2b9e4e95 P	58	if (!ossl_prov_is_running())
	59	return NULL;
	60
e077455e	61	if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL)
148176ca	62	ctx->provctx = provctx;
e3405a4a P	63	return ctx;
	64	}
	65
	66	static void kdf_sshkdf_free(void *vctx)
	67	{
	68	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
	69
3c659415 P	70	if (ctx != NULL) {
	71	kdf_sshkdf_reset(ctx);
	72	OPENSSL_free(ctx);
	73	}
e3405a4a P	74	}
	75
	76	static void kdf_sshkdf_reset(void *vctx)
	77	{
	78	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
0577959c	79	void *provctx = ctx->provctx;
e3405a4a	80
a1de4680	81	ossl_prov_digest_reset(&ctx->digest);
e3405a4a P	82	OPENSSL_clear_free(ctx->key, ctx->key_len);
	83	OPENSSL_clear_free(ctx->xcghash, ctx->xcghash_len);
	84	OPENSSL_clear_free(ctx->session_id, ctx->session_id_len);
	85	memset(ctx, 0, sizeof(*ctx));
0577959c	86	ctx->provctx = provctx;
e3405a4a P	87	}
e3405a4a P	88
59558f9d P	89	static void kdf_sshkdf_dup(void vctx)
	90	{
	91	const KDF_SSHKDF src = (const KDF_SSHKDF )vctx;
	92	KDF_SSHKDF *dest;
	93
	94	dest = kdf_sshkdf_new(src->provctx);
	95	if (dest != NULL) {
	96	if (!ossl_prov_memdup(src->key, src->key_len,
	97	&dest->key, &dest->key_len)
	98	\|\| !ossl_prov_memdup(src->xcghash, src->xcghash_len,
	99	&dest->xcghash , &dest->xcghash_len)
	100	\|\| !ossl_prov_memdup(src->session_id, src->session_id_len,
	101	&dest->session_id , &dest->session_id_len)
	102	\|\| !ossl_prov_digest_copy(&dest->digest, &src->digest))
	103	goto err;
	104	dest->type = src->type;
	105	}
	106	return dest;
	107
	108	err:
	109	kdf_sshkdf_free(dest);
	110	return NULL;
	111	}
	112
e3405a4a P	113	static int sshkdf_set_membuf(unsigned char *dst, size_t dst_len,
	114	const OSSL_PARAM *p)
	115	{
	116	OPENSSL_clear_free(dst, dst_len);
	117	*dst = NULL;
d2217c88	118	*dst_len = 0;
e3405a4a P	119	return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
	120	}
	121
3469b388 P	122	static int kdf_sshkdf_derive(void vctx, unsigned char key, size_t keylen,
3469b388 P	123	const OSSL_PARAM params[])
e3405a4a P	124	{
e3405a4a P	125	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
2b9e4e95 P	126	const EVP_MD *md;
2b9e4e95 P	127
3469b388	128	if (!ossl_prov_is_running() \|\| !kdf_sshkdf_set_ctx_params(ctx, params))
2b9e4e95	129	return 0;
e3405a4a	130
2b9e4e95	131	md = ossl_prov_digest_md(&ctx->digest);
a1de4680	132	if (md == NULL) {
e3405a4a P	133	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
	134	return 0;
	135	}
	136	if (ctx->key == NULL) {
	137	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
	138	return 0;
	139	}
	140	if (ctx->xcghash == NULL) {
	141	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_XCGHASH);
	142	return 0;
	143	}
	144	if (ctx->session_id == NULL) {
	145	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SESSION_ID);
	146	return 0;
	147	}
	148	if (ctx->type == 0) {
	149	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_TYPE);
	150	return 0;
	151	}
a1de4680	152	return SSHKDF(md, ctx->key, ctx->key_len,
e3405a4a P	153	ctx->xcghash, ctx->xcghash_len,
	154	ctx->session_id, ctx->session_id_len,
	155	ctx->type, key, keylen);
	156	}
	157
	158	static int kdf_sshkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
	159	{
	160	const OSSL_PARAM *p;
	161	KDF_SSHKDF *ctx = vctx;
a829b735	162	OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
e3405a4a	163
c983a0e5 P	164	if (params == NULL)
	165	return 1;
	166
a1de4680 P	167	if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
a1de4680 P	168	return 0;
e3405a4a P	169
	170	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
	171	if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p))
	172	return 0;
	173
	174	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_XCGHASH))
	175	!= NULL)
	176	if (!sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p))
	177	return 0;
	178
	179	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_SESSION_ID))
	180	!= NULL)
	181	if (!sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p))
	182	return 0;
	183
	184	if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SSHKDF_TYPE))
	185	!= NULL) {
270a5ce1 JC	186	const char *kdftype;
	187
	188	if (!OSSL_PARAM_get_utf8_string_ptr(p, &kdftype))
	189	return 0;
a8eb71ad RL	190	/* Expect one character (byte in this case) */
a8eb71ad RL	191	if (kdftype == NULL \|\| p->data_size != 1)
e3405a4a	192	return 0;
270a5ce1	193	if (kdftype[0] < 65 \|\| kdftype[0] > 70) {
e3405a4a P	194	ERR_raise(ERR_LIB_PROV, PROV_R_VALUE_ERROR);
	195	return 0;
	196	}
270a5ce1	197	ctx->type = kdftype[0];
e3405a4a P	198	}
	199	return 1;
	200	}
	201
1e8e5c60 P	202	static const OSSL_PARAM kdf_sshkdf_settable_ctx_params(ossl_unused void ctx,
1e8e5c60 P	203	ossl_unused void *p_ctx)
e3405a4a P	204	{
	205	static const OSSL_PARAM known_settable_ctx_params[] = {
	206	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
	207	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
	208	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
	209	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_XCGHASH, NULL, 0),
	210	OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SSHKDF_SESSION_ID, NULL, 0),
	211	OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_SSHKDF_TYPE, NULL, 0),
	212	OSSL_PARAM_END
	213	};
	214	return known_settable_ctx_params;
	215	}
	216
	217	static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
	218	{
	219	OSSL_PARAM *p;
	220
	221	if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
	222	return OSSL_PARAM_set_size_t(p, SIZE_MAX);
	223	return -2;
	224	}
	225
1e8e5c60 P	226	static const OSSL_PARAM kdf_sshkdf_gettable_ctx_params(ossl_unused void ctx,
1e8e5c60 P	227	ossl_unused void *p_ctx)
e3405a4a P	228	{
	229	static const OSSL_PARAM known_gettable_ctx_params[] = {
	230	OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
	231	OSSL_PARAM_END
	232	};
	233	return known_gettable_ctx_params;
	234	}
	235
1be63951	236	const OSSL_DISPATCH ossl_kdf_sshkdf_functions[] = {
e3405a4a	237	{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_sshkdf_new },
59558f9d	238	{ OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_sshkdf_dup },
e3405a4a P	239	{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_sshkdf_free },
	240	{ OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_sshkdf_reset },
	241	{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_sshkdf_derive },
	242	{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
	243	(void(*)(void))kdf_sshkdf_settable_ctx_params },
	244	{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_set_ctx_params },
	245	{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
	246	(void(*)(void))kdf_sshkdf_gettable_ctx_params },
	247	{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_sshkdf_get_ctx_params },
1e6bd31e	248	OSSL_DISPATCH_END
e3405a4a P	249	};
	250
	251	static int SSHKDF(const EVP_MD *evp_md,
	252	const unsigned char *key, size_t key_len,
	253	const unsigned char *xcghash, size_t xcghash_len,
	254	const unsigned char *session_id, size_t session_id_len,
	255	char type, unsigned char *okey, size_t okey_len)
	256	{
	257	EVP_MD_CTX *md = NULL;
	258	unsigned char digest[EVP_MAX_MD_SIZE];
	259	unsigned int dsize = 0;
	260	size_t cursize = 0;
	261	int ret = 0;
	262
	263	md = EVP_MD_CTX_new();
	264	if (md == NULL)
	265	return 0;
	266
	267	if (!EVP_DigestInit_ex(md, evp_md, NULL))
	268	goto out;
	269
	270	if (!EVP_DigestUpdate(md, key, key_len))
	271	goto out;
	272
	273	if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
	274	goto out;
	275
	276	if (!EVP_DigestUpdate(md, &type, 1))
	277	goto out;
	278
	279	if (!EVP_DigestUpdate(md, session_id, session_id_len))
	280	goto out;
	281
	282	if (!EVP_DigestFinal_ex(md, digest, &dsize))
	283	goto out;
	284
	285	if (okey_len < dsize) {
	286	memcpy(okey, digest, okey_len);
	287	ret = 1;
	288	goto out;
	289	}
	290
	291	memcpy(okey, digest, dsize);
	292
	293	for (cursize = dsize; cursize < okey_len; cursize += dsize) {
	294
	295	if (!EVP_DigestInit_ex(md, evp_md, NULL))
	296	goto out;
	297
	298	if (!EVP_DigestUpdate(md, key, key_len))
	299	goto out;
	300
	301	if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
	302	goto out;
	303
	304	if (!EVP_DigestUpdate(md, okey, cursize))
	305	goto out;
	306
	307	if (!EVP_DigestFinal_ex(md, digest, &dsize))
	308	goto out;
	309
	310	if (okey_len < cursize + dsize) {
	311	memcpy(okey + cursize, digest, okey_len - cursize);
	312	ret = 1;
313	goto out;
314	}
315
316	memcpy(okey + cursize, digest, dsize);
317	}
318
319	ret = 1;
320
321	out:
322	EVP_MD_CTX_free(md);
323	OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);
324	return ret;
325	}
326