/src/openssl/providers/implementations/kdfs/sshkdf.c

Source
/*
 * 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
 */

#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/fips.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/sshkdf.inc"

/* 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;
    OSSL_FIPS_IND_DECLARE
} KDF_SSHKDF;

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

    if (!ossl_prov_is_running())
        return NULL;

#ifdef FIPS_MODULE
    /*
     * Normally we'd want a call to ossl_deferred_self_test() here, but
     * according to FIPS 140-3 10.3.A Note18: SSH KDF is not required, since
     * it is sufficient to self-test the underlying SHA hash functions.
     * The underlying hash functions are implicitly tested when the hash is
     * instantiated, so we do not need to have an explicit test here.
     */
#endif

    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL) {
        ctx->provctx = provctx;
        OSSL_FIPS_IND_INIT(ctx)
    }
    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;
        OSSL_FIPS_IND_COPY(dest, src)
    }
    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);
}

#ifdef FIPS_MODULE
static int fips_digest_check_passed(KDF_SSHKDF *ctx, const EVP_MD *md)
{
    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
    /*
     * Perform digest check
     *
     * According to NIST SP 800-135r1 section 5.2, the valid hash functions are
     * specified in FIPS 180-3. ACVP also only lists the same set of hash
     * functions.
     */
    int digest_unapproved = !EVP_MD_is_a(md, SN_sha1)
        && !EVP_MD_is_a(md, SN_sha224)
        && !EVP_MD_is_a(md, SN_sha256)
        && !EVP_MD_is_a(md, SN_sha384)
        && !EVP_MD_is_a(md, SN_sha512);

    if (digest_unapproved) {
        if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0,
                libctx, "SSHKDF", "Digest",
                ossl_fips_config_sshkdf_digest_check)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED);
            return 0;
        }
    }
    return 1;
}

static int fips_key_check_passed(KDF_SSHKDF *ctx)
{
    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
    int key_approved = ossl_kdf_check_key_size(ctx->key_len);

    if (!key_approved) {
        if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE1,
                libctx, "SSHKDF", "Key size",
                ossl_fips_config_sshkdf_key_check)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
            return 0;
        }
    }
    return 1;
}
#endif

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[])
{
    struct sshkdf_set_ctx_params_st p;
    KDF_SSHKDF *ctx = vctx;
    OSSL_LIB_CTX *provctx;

    if (ctx == NULL || !sshkdf_set_ctx_params_decoder(params, &p))
        return 0;

    provctx = PROV_LIBCTX_OF(ctx->provctx);

    if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(ctx, OSSL_FIPS_IND_SETTABLE0, p.ind_d))
        return 0;
    if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(ctx, OSSL_FIPS_IND_SETTABLE1, p.ind_k))
        return 0;

    if (p.digest != NULL) {
        const EVP_MD *md = 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;
        }

#ifdef FIPS_MODULE
        if (!fips_digest_check_passed(ctx, md))
            return 0;
#endif
    }

    if (p.key != NULL) {
        if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p.key))
            return 0;

#ifdef FIPS_MODULE
        if (!fips_key_check_passed(ctx))
            return 0;
#endif
    }

    if (p.xcg != NULL
        && !sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p.xcg))
        return 0;

    if (p.sid != NULL
        && !sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p.sid))
        return 0;

    if (p.type != NULL) {
        const char *kdftype;

        if (!OSSL_PARAM_get_utf8_string_ptr(p.type, &kdftype))
            return 0;
        /* Expect one character (byte in this case) */
        if (kdftype == NULL || p.type->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)
{
    return sshkdf_set_ctx_params_list;
}

static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    KDF_SSHKDF *ctx = (KDF_SSHKDF *)vctx;
    struct sshkdf_get_ctx_params_st p;

    if (ctx == NULL || !sshkdf_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_sshkdf_gettable_ctx_params(ossl_unused void *ctx,
    ossl_unused void *p_ctx)
{
    return sshkdf_get_ctx_params_list;
}

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;
}

Coverage Report

Created: 2026-02-22 06:11

Line	Count	Source
1		/*
2		* Copyright 2018-2025 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the Apache License 2.0 (the "License"). You may not use
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>
16		#include <openssl/proverr.h>
17		#include "internal/cryptlib.h"
18		#include "internal/fips.h"
19		#include "internal/numbers.h"
20		#include "crypto/evp.h"
21		#include "prov/provider_ctx.h"
22		#include "prov/providercommon.h"
23		#include "prov/implementations.h"
24		#include "prov/provider_util.h"
25		#include "prov/securitycheck.h"
26		#include "providers/implementations/kdfs/sshkdf.inc"
27
28		/* See RFC 4253, Section 7.2 */
29		static OSSL_FUNC_kdf_newctx_fn kdf_sshkdf_new;
30		static OSSL_FUNC_kdf_dupctx_fn kdf_sshkdf_dup;
31		static OSSL_FUNC_kdf_freectx_fn kdf_sshkdf_free;
32		static OSSL_FUNC_kdf_reset_fn kdf_sshkdf_reset;
33		static OSSL_FUNC_kdf_derive_fn kdf_sshkdf_derive;
34		static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_sshkdf_settable_ctx_params;
35		static OSSL_FUNC_kdf_set_ctx_params_fn kdf_sshkdf_set_ctx_params;
36		static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_sshkdf_gettable_ctx_params;
37		static OSSL_FUNC_kdf_get_ctx_params_fn kdf_sshkdf_get_ctx_params;
38
39		static int SSHKDF(const EVP_MD *evp_md,
40		const unsigned char *key, size_t key_len,
41		const unsigned char *xcghash, size_t xcghash_len,
42		const unsigned char *session_id, size_t session_id_len,
43		char type, unsigned char *okey, size_t okey_len);
44
45		typedef struct {
46		void *provctx;
47		PROV_DIGEST digest;
48		unsigned char key; / K */
49		size_t key_len;
50		unsigned char xcghash; / H */
51		size_t xcghash_len;
52		char type; /* X */
53		unsigned char *session_id;
54		size_t session_id_len;
55		OSSL_FIPS_IND_DECLARE
56		} KDF_SSHKDF;
57
58		static void kdf_sshkdf_new(void provctx)
59	0	{
60	0	KDF_SSHKDF *ctx;
61
62	0	if (!ossl_prov_is_running())
63	0	return NULL;
64
65		#ifdef FIPS_MODULE
66		/*
67		* Normally we'd want a call to ossl_deferred_self_test() here, but
68		* according to FIPS 140-3 10.3.A Note18: SSH KDF is not required, since
69		* it is sufficient to self-test the underlying SHA hash functions.
70		* The underlying hash functions are implicitly tested when the hash is
71		* instantiated, so we do not need to have an explicit test here.
72		*/
73		#endif
74
75	0	if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL) {
76	0	ctx->provctx = provctx;
77	0	OSSL_FIPS_IND_INIT(ctx)
78	0	}
79	0	return ctx;
80	0	}
81
82		static void kdf_sshkdf_free(void *vctx)
83	0	{
84	0	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
85
86	0	if (ctx != NULL) {
87	0	kdf_sshkdf_reset(ctx);
88	0	OPENSSL_free(ctx);
89	0	}
90	0	}
91
92		static void kdf_sshkdf_reset(void *vctx)
93	0	{
94	0	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
95	0	void *provctx = ctx->provctx;
96
97	0	ossl_prov_digest_reset(&ctx->digest);
98	0	OPENSSL_clear_free(ctx->key, ctx->key_len);
99	0	OPENSSL_clear_free(ctx->xcghash, ctx->xcghash_len);
100	0	OPENSSL_clear_free(ctx->session_id, ctx->session_id_len);
101	0	memset(ctx, 0, sizeof(*ctx));
102	0	ctx->provctx = provctx;
103	0	}
104
105		static void kdf_sshkdf_dup(void vctx)
106	0	{
107	0	const KDF_SSHKDF src = (const KDF_SSHKDF )vctx;
108	0	KDF_SSHKDF *dest;
109
110	0	dest = kdf_sshkdf_new(src->provctx);
111	0	if (dest != NULL) {
112	0	if (!ossl_prov_memdup(src->key, src->key_len,
113	0	&dest->key, &dest->key_len)
114	0	\|\| !ossl_prov_memdup(src->xcghash, src->xcghash_len,
115	0	&dest->xcghash, &dest->xcghash_len)
116	0	\|\| !ossl_prov_memdup(src->session_id, src->session_id_len,
117	0	&dest->session_id, &dest->session_id_len)
118	0	\|\| !ossl_prov_digest_copy(&dest->digest, &src->digest))
119	0	goto err;
120	0	dest->type = src->type;
121	0	OSSL_FIPS_IND_COPY(dest, src)
122	0	}
123	0	return dest;
124
125	0	err:
126	0	kdf_sshkdf_free(dest);
127	0	return NULL;
128	0	}
129
130		static int sshkdf_set_membuf(unsigned char *dst, size_t dst_len,
131		const OSSL_PARAM *p)
132	0	{
133	0	OPENSSL_clear_free(dst, dst_len);
134	0	*dst = NULL;
135	0	*dst_len = 0;
136	0	return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
137	0	}
138
139		#ifdef FIPS_MODULE
140		static int fips_digest_check_passed(KDF_SSHKDF ctx, const EVP_MD md)
141		{
142		OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
143		/*
144		* Perform digest check
145		*
146		* According to NIST SP 800-135r1 section 5.2, the valid hash functions are
147		* specified in FIPS 180-3. ACVP also only lists the same set of hash
148		* functions.
149		*/
150		int digest_unapproved = !EVP_MD_is_a(md, SN_sha1)
151		&& !EVP_MD_is_a(md, SN_sha224)
152		&& !EVP_MD_is_a(md, SN_sha256)
153		&& !EVP_MD_is_a(md, SN_sha384)
154		&& !EVP_MD_is_a(md, SN_sha512);
155
156		if (digest_unapproved) {
157		if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0,
158		libctx, "SSHKDF", "Digest",
159		ossl_fips_config_sshkdf_digest_check)) {
160		ERR_raise(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED);
161		return 0;
162		}
163		}
164		return 1;
165		}
166
167		static int fips_key_check_passed(KDF_SSHKDF *ctx)
168		{
169		OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
170		int key_approved = ossl_kdf_check_key_size(ctx->key_len);
171
172		if (!key_approved) {
173		if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE1,
174		libctx, "SSHKDF", "Key size",
175		ossl_fips_config_sshkdf_key_check)) {
176		ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
177		return 0;
178		}
179		}
180		return 1;
181		}
182		#endif
183
184		static int kdf_sshkdf_derive(void vctx, unsigned char key, size_t keylen,
185		const OSSL_PARAM params[])
186	0	{
187	0	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
188	0	const EVP_MD *md;
189
190	0	if (!ossl_prov_is_running() \|\| !kdf_sshkdf_set_ctx_params(ctx, params))
191	0	return 0;
192
193	0	md = ossl_prov_digest_md(&ctx->digest);
194	0	if (md == NULL) {
195	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
196	0	return 0;
197	0	}
198	0	if (ctx->key == NULL) {
199	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
200	0	return 0;
201	0	}
202	0	if (ctx->xcghash == NULL) {
203	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_XCGHASH);
204	0	return 0;
205	0	}
206	0	if (ctx->session_id == NULL) {
207	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SESSION_ID);
208	0	return 0;
209	0	}
210	0	if (ctx->type == 0) {
211	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_TYPE);
212	0	return 0;
213	0	}
214
215	0	return SSHKDF(md, ctx->key, ctx->key_len,
216	0	ctx->xcghash, ctx->xcghash_len,
217	0	ctx->session_id, ctx->session_id_len,
218	0	ctx->type, key, keylen);
219	0	}
220
221		static int kdf_sshkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
222	0	{
223	0	struct sshkdf_set_ctx_params_st p;
224	0	KDF_SSHKDF *ctx = vctx;
225	0	OSSL_LIB_CTX *provctx;
226
227	0	if (ctx == NULL \|\| !sshkdf_set_ctx_params_decoder(params, &p))
228	0	return 0;
229
230	0	provctx = PROV_LIBCTX_OF(ctx->provctx);
231
232	0	if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(ctx, OSSL_FIPS_IND_SETTABLE0, p.ind_d))
233	0	return 0;
234	0	if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(ctx, OSSL_FIPS_IND_SETTABLE1, p.ind_k))
235	0	return 0;
236
237	0	if (p.digest != NULL) {
238	0	const EVP_MD *md = NULL;
239
240	0	if (!ossl_prov_digest_load(&ctx->digest, p.digest, p.propq, provctx))
241	0	return 0;
242
243	0	md = ossl_prov_digest_md(&ctx->digest);
244	0	if (EVP_MD_xof(md)) {
245	0	ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
246	0	return 0;
247	0	}
248
249		#ifdef FIPS_MODULE
250		if (!fips_digest_check_passed(ctx, md))
251		return 0;
252		#endif
253	0	}
254
255	0	if (p.key != NULL) {
256	0	if (!sshkdf_set_membuf(&ctx->key, &ctx->key_len, p.key))
257	0	return 0;
258
259		#ifdef FIPS_MODULE
260		if (!fips_key_check_passed(ctx))
261		return 0;
262		#endif
263	0	}
264
265	0	if (p.xcg != NULL
266	0	&& !sshkdf_set_membuf(&ctx->xcghash, &ctx->xcghash_len, p.xcg))
267	0	return 0;
268
269	0	if (p.sid != NULL
270	0	&& !sshkdf_set_membuf(&ctx->session_id, &ctx->session_id_len, p.sid))
271	0	return 0;
272
273	0	if (p.type != NULL) {
274	0	const char *kdftype;
275
276	0	if (!OSSL_PARAM_get_utf8_string_ptr(p.type, &kdftype))
277	0	return 0;
278		/* Expect one character (byte in this case) */
279	0	if (kdftype == NULL \|\| p.type->data_size != 1)
280	0	return 0;
281	0	if (kdftype[0] < 65 \|\| kdftype[0] > 70) {
282	0	ERR_raise(ERR_LIB_PROV, PROV_R_VALUE_ERROR);
283	0	return 0;
284	0	}
285	0	ctx->type = kdftype[0];
286	0	}
287	0	return 1;
288	0	}
289
290		static const OSSL_PARAM kdf_sshkdf_settable_ctx_params(ossl_unused void ctx,
291		ossl_unused void *p_ctx)
292	0	{
293	0	return sshkdf_set_ctx_params_list;
294	0	}
295
296		static int kdf_sshkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
297	0	{
298	0	KDF_SSHKDF ctx = (KDF_SSHKDF )vctx;
299	0	struct sshkdf_get_ctx_params_st p;
300
301	0	if (ctx == NULL \|\| !sshkdf_get_ctx_params_decoder(params, &p))
302	0	return 0;
303
304	0	if (p.size != NULL && !OSSL_PARAM_set_size_t(p.size, SIZE_MAX))
305	0	return 0;
306
307	0	if (!OSSL_FIPS_IND_GET_CTX_FROM_PARAM(ctx, p.ind))
308	0	return 0;
309	0	return 1;
310	0	}
311
312		static const OSSL_PARAM kdf_sshkdf_gettable_ctx_params(ossl_unused void ctx,
313		ossl_unused void *p_ctx)
314	0	{
315	0	return sshkdf_get_ctx_params_list;
316	0	}
317
318		const OSSL_DISPATCH ossl_kdf_sshkdf_functions[] = {
319		{ OSSL_FUNC_KDF_NEWCTX, (void (*)(void))kdf_sshkdf_new },
320		{ OSSL_FUNC_KDF_DUPCTX, (void (*)(void))kdf_sshkdf_dup },
321		{ OSSL_FUNC_KDF_FREECTX, (void (*)(void))kdf_sshkdf_free },
322		{ OSSL_FUNC_KDF_RESET, (void (*)(void))kdf_sshkdf_reset },
323		{ OSSL_FUNC_KDF_DERIVE, (void (*)(void))kdf_sshkdf_derive },
324		{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
325		(void (*)(void))kdf_sshkdf_settable_ctx_params },
326		{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void (*)(void))kdf_sshkdf_set_ctx_params },
327		{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
328		(void (*)(void))kdf_sshkdf_gettable_ctx_params },
329		{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void (*)(void))kdf_sshkdf_get_ctx_params },
330		OSSL_DISPATCH_END
331		};
332
333		static int SSHKDF(const EVP_MD *evp_md,
334		const unsigned char *key, size_t key_len,
335		const unsigned char *xcghash, size_t xcghash_len,
336		const unsigned char *session_id, size_t session_id_len,
337		char type, unsigned char *okey, size_t okey_len)
338	0	{
339	0	EVP_MD_CTX *md = NULL;
340	0	unsigned char digest[EVP_MAX_MD_SIZE];
341	0	unsigned int dsize = 0;
342	0	size_t cursize = 0;
343	0	int ret = 0;
344
345	0	md = EVP_MD_CTX_new();
346	0	if (md == NULL)
347	0	return 0;
348
349	0	if (!EVP_DigestInit_ex(md, evp_md, NULL))
350	0	goto out;
351
352	0	if (!EVP_DigestUpdate(md, key, key_len))
353	0	goto out;
354
355	0	if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
356	0	goto out;
357
358	0	if (!EVP_DigestUpdate(md, &type, 1))
359	0	goto out;
360
361	0	if (!EVP_DigestUpdate(md, session_id, session_id_len))
362	0	goto out;
363
364	0	if (!EVP_DigestFinal_ex(md, digest, &dsize))
365	0	goto out;
366
367	0	if (okey_len < dsize) {
368	0	memcpy(okey, digest, okey_len);
369	0	ret = 1;
370	0	goto out;
371	0	}
372
373	0	memcpy(okey, digest, dsize);
374
375	0	for (cursize = dsize; cursize < okey_len; cursize += dsize) {
376
377	0	if (!EVP_DigestInit_ex(md, evp_md, NULL))
378	0	goto out;
379
380	0	if (!EVP_DigestUpdate(md, key, key_len))
381	0	goto out;
382
383	0	if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
384	0	goto out;
385
386	0	if (!EVP_DigestUpdate(md, okey, cursize))
387	0	goto out;
388
389	0	if (!EVP_DigestFinal_ex(md, digest, &dsize))
390	0	goto out;
391
392	0	if (okey_len < cursize + dsize) {
393	0	memcpy(okey + cursize, digest, okey_len - cursize);
394	0	ret = 1;
395	0	goto out;
396	0	}
397
398	0	memcpy(okey + cursize, digest, dsize);
399	0	}
400
401	0	ret = 1;
402
403	0	out:
404	0	EVP_MD_CTX_free(md);
405	0	OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);
406	0	return ret;
407	0	}