/src/openssl/providers/implementations/exchange/dh_exch.c

Source
/*
 * Copyright 2019-2025 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
 */

/*
 * DH low level APIs are deprecated for public use, but still ok for
 * internal use.
 */
#include "internal/deprecated.h"

#include <string.h>
#include <openssl/crypto.h>
#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
#include <openssl/dh.h>
#include <openssl/err.h>
#include <openssl/proverr.h>
#include <openssl/params.h>
#include "internal/cryptlib.h"
#include "prov/providercommon.h"
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/securitycheck.h"
#include "crypto/dh.h"
#include "providers/implementations/exchange/dh_exch.inc"

static OSSL_FUNC_keyexch_newctx_fn dh_newctx;
static OSSL_FUNC_keyexch_init_fn dh_init;
static OSSL_FUNC_keyexch_set_peer_fn dh_set_peer;
static OSSL_FUNC_keyexch_derive_fn dh_derive;
static OSSL_FUNC_keyexch_freectx_fn dh_freectx;
static OSSL_FUNC_keyexch_dupctx_fn dh_dupctx;
static OSSL_FUNC_keyexch_set_ctx_params_fn dh_set_ctx_params;
static OSSL_FUNC_keyexch_settable_ctx_params_fn dh_settable_ctx_params;
static OSSL_FUNC_keyexch_get_ctx_params_fn dh_get_ctx_params;
static OSSL_FUNC_keyexch_gettable_ctx_params_fn dh_gettable_ctx_params;

/*
 * This type is only really used to handle some legacy related functionality.
 * If you need to use other KDF's (such as SSKDF) just use PROV_DH_KDF_NONE
 * here and then create and run a KDF after the key is derived.
 * Note that X942 has 2 variants of key derivation:
 *   (1) DH_KDF_X9_42_ASN1 - which contains an ANS1 encoded object that has
 *   the counter embedded in it.
 *   (2) DH_KDF_X941_CONCAT - which is the same as ECDH_X963_KDF (which can be
 *       done by creating a "X963KDF".
 */
enum kdf_type {
    PROV_DH_KDF_NONE = 0,
    PROV_DH_KDF_X9_42_ASN1
};

/*
 * What's passed as an actual key is defined by the KEYMGMT interface.
 * We happen to know that our KEYMGMT simply passes DH structures, so
 * we use that here too.
 */

typedef struct {
    OSSL_LIB_CTX *libctx;
    DH *dh;
    DH *dhpeer;
    unsigned int pad : 1;

    /* DH KDF */
    /* KDF (if any) to use for DH */
    enum kdf_type kdf_type;
    /* Message digest to use for key derivation */
    EVP_MD *kdf_md;
    /* User key material */
    unsigned char *kdf_ukm;
    size_t kdf_ukmlen;
    /* KDF output length */
    size_t kdf_outlen;
    char *kdf_cekalg;
    OSSL_FIPS_IND_DECLARE
} PROV_DH_CTX;

static void *dh_newctx(void *provctx)
{
    PROV_DH_CTX *pdhctx;

    if (!ossl_prov_is_running())
        return NULL;

    pdhctx = OPENSSL_zalloc(sizeof(PROV_DH_CTX));
    if (pdhctx == NULL)
        return NULL;
    OSSL_FIPS_IND_INIT(pdhctx)
    pdhctx->libctx = PROV_LIBCTX_OF(provctx);
    pdhctx->kdf_type = PROV_DH_KDF_NONE;
    return pdhctx;
}

#ifdef FIPS_MODULE
static int dh_check_key(PROV_DH_CTX *ctx)
{
    int key_approved = ossl_dh_check_key(ctx->dh);

    if (!key_approved) {
        if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0,
                                         ctx->libctx, "DH Init", "DH Key",
                                         ossl_fips_config_securitycheck_enabled)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
            return 0;
        }
    }
    return 1;
}

static int digest_check(PROV_DH_CTX *ctx, const EVP_MD *md)
{
    return ossl_fips_ind_digest_exch_check(OSSL_FIPS_IND_GET(ctx),
                                           OSSL_FIPS_IND_SETTABLE1, ctx->libctx,
                                           md, "DH Set Ctx");
}
#endif

static int dh_init(void *vpdhctx, void *vdh, const OSSL_PARAM params[])
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;

    if (!ossl_prov_is_running()
            || pdhctx == NULL
            || vdh == NULL
            || !DH_up_ref(vdh))
        return 0;
    DH_free(pdhctx->dh);
    pdhctx->dh = vdh;
    pdhctx->kdf_type = PROV_DH_KDF_NONE;

    OSSL_FIPS_IND_SET_APPROVED(pdhctx)
    if (!dh_set_ctx_params(pdhctx, params))
        return 0;
#ifdef FIPS_MODULE
    if (!dh_check_key(pdhctx))
        return 0;
#endif
    return 1;
}

/* The 2 parties must share the same domain parameters */
static int dh_match_params(DH *priv, DH *peer)
{
    int ret;
    FFC_PARAMS *dhparams_priv = ossl_dh_get0_params(priv);
    FFC_PARAMS *dhparams_peer = ossl_dh_get0_params(peer);

    ret = dhparams_priv != NULL
          && dhparams_peer != NULL
          && ossl_ffc_params_cmp(dhparams_priv, dhparams_peer, 1);
    if (!ret)
        ERR_raise(ERR_LIB_PROV, PROV_R_MISMATCHING_DOMAIN_PARAMETERS);
    return ret;
}

static int dh_set_peer(void *vpdhctx, void *vdh)
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;

    if (!ossl_prov_is_running()
            || pdhctx == NULL
            || vdh == NULL
            || !dh_match_params(vdh, pdhctx->dh)
            || !DH_up_ref(vdh))
        return 0;
    DH_free(pdhctx->dhpeer);
    pdhctx->dhpeer = vdh;
    return 1;
}

static int dh_plain_derive(void *vpdhctx,
                           unsigned char *secret, size_t *secretlen,
                           size_t outlen, unsigned int pad)
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
    int ret;
    size_t dhsize;
    const BIGNUM *pub_key = NULL;

    if (pdhctx->dh == NULL || pdhctx->dhpeer == NULL) {
        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
        return 0;
    }

    dhsize = (size_t)DH_size(pdhctx->dh);
    if (secret == NULL) {
        *secretlen = dhsize;
        return 1;
    }
    if (outlen < dhsize) {
        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
        return 0;
    }

    DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
    if (pad)
        ret = DH_compute_key_padded(secret, pub_key, pdhctx->dh);
    else
        ret = DH_compute_key(secret, pub_key, pdhctx->dh);
    if (ret <= 0)
        return 0;

    *secretlen = ret;
    return 1;
}

static int dh_X9_42_kdf_derive(void *vpdhctx, unsigned char *secret,
                               size_t *secretlen, size_t outlen)
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
    unsigned char *stmp = NULL;
    size_t stmplen;
    int ret = 0;

    if (secret == NULL) {
        *secretlen = pdhctx->kdf_outlen;
        return 1;
    }

    if (pdhctx->kdf_outlen > outlen) {
        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
        return 0;
    }
    if (!dh_plain_derive(pdhctx, NULL, &stmplen, 0, 1))
        return 0;
    if ((stmp = OPENSSL_secure_malloc(stmplen)) == NULL)
        return 0;
    if (!dh_plain_derive(pdhctx, stmp, &stmplen, stmplen, 1))
        goto err;

    /* Do KDF stuff */
    if (pdhctx->kdf_type == PROV_DH_KDF_X9_42_ASN1) {
        if (!ossl_dh_kdf_X9_42_asn1(secret, pdhctx->kdf_outlen,
                                    stmp, stmplen,
                                    pdhctx->kdf_cekalg,
                                    pdhctx->kdf_ukm,
                                    pdhctx->kdf_ukmlen,
                                    pdhctx->kdf_md,
                                    pdhctx->libctx, NULL))
            goto err;
    }
    *secretlen = pdhctx->kdf_outlen;
    ret = 1;
err:
    OPENSSL_secure_clear_free(stmp, stmplen);
    return ret;
}

static int dh_derive(void *vpdhctx, unsigned char *secret,
                     size_t *psecretlen, size_t outlen)
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;

    if (!ossl_prov_is_running())
        return 0;

    switch (pdhctx->kdf_type) {
        case PROV_DH_KDF_NONE:
            return dh_plain_derive(pdhctx, secret, psecretlen, outlen,
                                   pdhctx->pad);
        case PROV_DH_KDF_X9_42_ASN1:
            return dh_X9_42_kdf_derive(pdhctx, secret, psecretlen, outlen);
        default:
            break;
    }
    return 0;
}

static void dh_freectx(void *vpdhctx)
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;

    OPENSSL_free(pdhctx->kdf_cekalg);
    DH_free(pdhctx->dh);
    DH_free(pdhctx->dhpeer);
    EVP_MD_free(pdhctx->kdf_md);
    OPENSSL_clear_free(pdhctx->kdf_ukm, pdhctx->kdf_ukmlen);

    OPENSSL_free(pdhctx);
}

static void *dh_dupctx(void *vpdhctx)
{
    PROV_DH_CTX *srcctx = (PROV_DH_CTX *)vpdhctx;
    PROV_DH_CTX *dstctx;

    if (!ossl_prov_is_running())
        return NULL;

    dstctx = OPENSSL_zalloc(sizeof(*srcctx));
    if (dstctx == NULL)
        return NULL;

    *dstctx = *srcctx;
    dstctx->dh = NULL;
    dstctx->dhpeer = NULL;
    dstctx->kdf_md = NULL;
    dstctx->kdf_ukm = NULL;
    dstctx->kdf_cekalg = NULL;

    if (srcctx->dh != NULL && !DH_up_ref(srcctx->dh))
        goto err;
    else
        dstctx->dh = srcctx->dh;

    if (srcctx->dhpeer != NULL && !DH_up_ref(srcctx->dhpeer))
        goto err;
    else
        dstctx->dhpeer = srcctx->dhpeer;

    if (srcctx->kdf_md != NULL && !EVP_MD_up_ref(srcctx->kdf_md))
        goto err;
    else
        dstctx->kdf_md = srcctx->kdf_md;

    /* Duplicate UKM data if present */
    if (srcctx->kdf_ukm != NULL && srcctx->kdf_ukmlen > 0) {
        dstctx->kdf_ukm = OPENSSL_memdup(srcctx->kdf_ukm,
                                         srcctx->kdf_ukmlen);
        if (dstctx->kdf_ukm == NULL)
            goto err;
    }

    if (srcctx->kdf_cekalg != NULL) {
        dstctx->kdf_cekalg = OPENSSL_strdup(srcctx->kdf_cekalg);
        if (dstctx->kdf_cekalg == NULL)
            goto err;
    }

    return dstctx;
err:
    dh_freectx(dstctx);
    return NULL;
}

static int dh_set_ctx_params(void *vpdhctx, const OSSL_PARAM params[])
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
    struct dh_set_ctx_params_st p;
    unsigned int pad;
    char name[80] = { '\0' }; /* should be big enough */
    char *str = NULL;

    if (pdhctx == NULL || !dh_set_ctx_params_decoder(params, &p))
        return 0;

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

    if (p.kdf != NULL) {
        str = name;
        if (!OSSL_PARAM_get_utf8_string(p.kdf, &str, sizeof(name)))
            return 0;

        if (name[0] == '\0')
            pdhctx->kdf_type = PROV_DH_KDF_NONE;
        else if (strcmp(name, OSSL_KDF_NAME_X942KDF_ASN1) == 0)
            pdhctx->kdf_type = PROV_DH_KDF_X9_42_ASN1;
        else
            return 0;
    }

    if (p.digest != NULL) {
        char mdprops[80] = { '\0' }; /* should be big enough */

        str = name;
        if (!OSSL_PARAM_get_utf8_string(p.digest, &str, sizeof(name)))
            return 0;

        str = mdprops;
        if (p.propq != NULL) {
            if (!OSSL_PARAM_get_utf8_string(p.propq, &str, sizeof(mdprops)))
                return 0;
        }

        EVP_MD_free(pdhctx->kdf_md);
        pdhctx->kdf_md = EVP_MD_fetch(pdhctx->libctx, name, mdprops);
        if (pdhctx->kdf_md == NULL)
            return 0;
        /* XOF digests are not allowed */
        if (EVP_MD_xof(pdhctx->kdf_md)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
            return 0;
        }
#ifdef FIPS_MODULE
        if (!digest_check(pdhctx, pdhctx->kdf_md)) {
            EVP_MD_free(pdhctx->kdf_md);
            pdhctx->kdf_md = NULL;
            return 0;
        }
#endif
    }

    if (p.len != NULL) {
        size_t outlen;

        if (!OSSL_PARAM_get_size_t(p.len, &outlen))
            return 0;
        pdhctx->kdf_outlen = outlen;
    }

    if (p.ukm != NULL) {
        void *tmp_ukm = NULL;
        size_t tmp_ukmlen;

        OPENSSL_free(pdhctx->kdf_ukm);
        pdhctx->kdf_ukm = NULL;
        pdhctx->kdf_ukmlen = 0;
        /* ukm is an optional field so it can be NULL */
        if (p.ukm->data != NULL && p.ukm->data_size != 0) {
            if (!OSSL_PARAM_get_octet_string(p.ukm, &tmp_ukm, 0, &tmp_ukmlen))
                return 0;
            pdhctx->kdf_ukm = tmp_ukm;
            pdhctx->kdf_ukmlen = tmp_ukmlen;
        }
    }

    if (p.pad != NULL) {
        if (!OSSL_PARAM_get_uint(p.pad, &pad))
            return 0;
        pdhctx->pad = pad ? 1 : 0;
    }

    if (p.cekalg != NULL) {
        str = name;

        OPENSSL_free(pdhctx->kdf_cekalg);
        pdhctx->kdf_cekalg = NULL;
        if (p.cekalg->data != NULL && p.cekalg->data_size != 0) {
            if (!OSSL_PARAM_get_utf8_string(p.cekalg, &str, sizeof(name)))
                return 0;
            pdhctx->kdf_cekalg = OPENSSL_strdup(name);
            if (pdhctx->kdf_cekalg == NULL)
                return 0;
        }
    }
    return 1;
}

static const OSSL_PARAM *dh_settable_ctx_params(ossl_unused void *vpdhctx,
                                                ossl_unused void *provctx)
{
    return dh_set_ctx_params_list;
}

static const OSSL_PARAM *dh_gettable_ctx_params(ossl_unused void *vpdhctx,
                                                ossl_unused void *provctx)
{
    return dh_get_ctx_params_list;
}

static int dh_get_ctx_params(void *vpdhctx, OSSL_PARAM params[])
{
    PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
    struct dh_get_ctx_params_st p;

    if (pdhctx == NULL || !dh_get_ctx_params_decoder(params, &p))
        return 0;

    if (p.kdf != NULL) {
        const char *kdf_type = NULL;

        switch (pdhctx->kdf_type) {
        case PROV_DH_KDF_NONE:
            kdf_type = "";
            break;
        case PROV_DH_KDF_X9_42_ASN1:
            kdf_type = OSSL_KDF_NAME_X942KDF_ASN1;
            break;
        default:
            return 0;
        }

        if (!OSSL_PARAM_set_utf8_string(p.kdf, kdf_type))
            return 0;
    }

    if (p.digest != NULL
            && !OSSL_PARAM_set_utf8_string(p.digest, pdhctx->kdf_md == NULL
                                           ? ""
                                           : EVP_MD_get0_name(pdhctx->kdf_md))) {
        return 0;
    }

    if (p.len != NULL && !OSSL_PARAM_set_size_t(p.len, pdhctx->kdf_outlen))
        return 0;

    if (p.ukm != NULL
        && !OSSL_PARAM_set_octet_ptr(p.ukm, pdhctx->kdf_ukm, pdhctx->kdf_ukmlen))
        return 0;

    if (p.cekalg != NULL
            && !OSSL_PARAM_set_utf8_string(p.cekalg, pdhctx->kdf_cekalg == NULL
                                           ? "" :  pdhctx->kdf_cekalg))
        return 0;

    if (!OSSL_FIPS_IND_GET_CTX_FROM_PARAM(pdhctx, p.ind))
        return 0;
    return 1;
}

const OSSL_DISPATCH ossl_dh_keyexch_functions[] = {
    { OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
    { OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
    { OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
    { OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
    { OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
    { OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
    { OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))dh_set_ctx_params },
    { OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS,
      (void (*)(void))dh_settable_ctx_params },
    { OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS, (void (*)(void))dh_get_ctx_params },
    { OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS,
      (void (*)(void))dh_gettable_ctx_params },
    OSSL_DISPATCH_END
};

Coverage Report

Created: 2025-10-28 06:56

Line	Count	Source
1		/*
2		* Copyright 2019-2025 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		/*
11		* DH low level APIs are deprecated for public use, but still ok for
12		* internal use.
13		*/
14		#include "internal/deprecated.h"
15
16		#include <string.h>
17		#include <openssl/crypto.h>
18		#include <openssl/core_dispatch.h>
19		#include <openssl/core_names.h>
20		#include <openssl/dh.h>
21		#include <openssl/err.h>
22		#include <openssl/proverr.h>
23		#include <openssl/params.h>
24		#include "internal/cryptlib.h"
25		#include "prov/providercommon.h"
26		#include "prov/implementations.h"
27		#include "prov/provider_ctx.h"
28		#include "prov/securitycheck.h"
29		#include "crypto/dh.h"
30		#include "providers/implementations/exchange/dh_exch.inc"
31
32		static OSSL_FUNC_keyexch_newctx_fn dh_newctx;
33		static OSSL_FUNC_keyexch_init_fn dh_init;
34		static OSSL_FUNC_keyexch_set_peer_fn dh_set_peer;
35		static OSSL_FUNC_keyexch_derive_fn dh_derive;
36		static OSSL_FUNC_keyexch_freectx_fn dh_freectx;
37		static OSSL_FUNC_keyexch_dupctx_fn dh_dupctx;
38		static OSSL_FUNC_keyexch_set_ctx_params_fn dh_set_ctx_params;
39		static OSSL_FUNC_keyexch_settable_ctx_params_fn dh_settable_ctx_params;
40		static OSSL_FUNC_keyexch_get_ctx_params_fn dh_get_ctx_params;
41		static OSSL_FUNC_keyexch_gettable_ctx_params_fn dh_gettable_ctx_params;
42
43		/*
44		* This type is only really used to handle some legacy related functionality.
45		* If you need to use other KDF's (such as SSKDF) just use PROV_DH_KDF_NONE
46		* here and then create and run a KDF after the key is derived.
47		* Note that X942 has 2 variants of key derivation:
48		* (1) DH_KDF_X9_42_ASN1 - which contains an ANS1 encoded object that has
49		* the counter embedded in it.
50		* (2) DH_KDF_X941_CONCAT - which is the same as ECDH_X963_KDF (which can be
51		* done by creating a "X963KDF".
52		*/
53		enum kdf_type {
54		PROV_DH_KDF_NONE = 0,
55		PROV_DH_KDF_X9_42_ASN1
56		};
57
58		/*
59		* What's passed as an actual key is defined by the KEYMGMT interface.
60		* We happen to know that our KEYMGMT simply passes DH structures, so
61		* we use that here too.
62		*/
63
64		typedef struct {
65		OSSL_LIB_CTX *libctx;
66		DH *dh;
67		DH *dhpeer;
68		unsigned int pad : 1;
69
70		/* DH KDF */
71		/* KDF (if any) to use for DH */
72		enum kdf_type kdf_type;
73		/* Message digest to use for key derivation */
74		EVP_MD *kdf_md;
75		/* User key material */
76		unsigned char *kdf_ukm;
77		size_t kdf_ukmlen;
78		/* KDF output length */
79		size_t kdf_outlen;
80		char *kdf_cekalg;
81		OSSL_FIPS_IND_DECLARE
82		} PROV_DH_CTX;
83
84		static void dh_newctx(void provctx)
85	0	{
86	0	PROV_DH_CTX *pdhctx;
87
88	0	if (!ossl_prov_is_running())
89	0	return NULL;
90
91	0	pdhctx = OPENSSL_zalloc(sizeof(PROV_DH_CTX));
92	0	if (pdhctx == NULL)
93	0	return NULL;
94	0	OSSL_FIPS_IND_INIT(pdhctx)
95	0	pdhctx->libctx = PROV_LIBCTX_OF(provctx);
96	0	pdhctx->kdf_type = PROV_DH_KDF_NONE;
97	0	return pdhctx;
98	0	}
99
100		#ifdef FIPS_MODULE
101		static int dh_check_key(PROV_DH_CTX *ctx)
102		{
103		int key_approved = ossl_dh_check_key(ctx->dh);
104
105		if (!key_approved) {
106		if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0,
107		ctx->libctx, "DH Init", "DH Key",
108		ossl_fips_config_securitycheck_enabled)) {
109		ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
110		return 0;
111		}
112		}
113		return 1;
114		}
115
116		static int digest_check(PROV_DH_CTX ctx, const EVP_MD md)
117		{
118		return ossl_fips_ind_digest_exch_check(OSSL_FIPS_IND_GET(ctx),
119		OSSL_FIPS_IND_SETTABLE1, ctx->libctx,
120		md, "DH Set Ctx");
121		}
122		#endif
123
124		static int dh_init(void vpdhctx, void vdh, const OSSL_PARAM params[])
125	0	{
126	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
127
128	0	if (!ossl_prov_is_running()
129	0	\|\| pdhctx == NULL
130	0	\|\| vdh == NULL
131	0	\|\| !DH_up_ref(vdh))
132	0	return 0;
133	0	DH_free(pdhctx->dh);
134	0	pdhctx->dh = vdh;
135	0	pdhctx->kdf_type = PROV_DH_KDF_NONE;
136
137	0	OSSL_FIPS_IND_SET_APPROVED(pdhctx)
138	0	if (!dh_set_ctx_params(pdhctx, params))
139	0	return 0;
140		#ifdef FIPS_MODULE
141		if (!dh_check_key(pdhctx))
142		return 0;
143		#endif
144	0	return 1;
145	0	}
146
147		/* The 2 parties must share the same domain parameters */
148		static int dh_match_params(DH priv, DH peer)
149	0	{
150	0	int ret;
151	0	FFC_PARAMS *dhparams_priv = ossl_dh_get0_params(priv);
152	0	FFC_PARAMS *dhparams_peer = ossl_dh_get0_params(peer);
153
154	0	ret = dhparams_priv != NULL
155	0	&& dhparams_peer != NULL
156	0	&& ossl_ffc_params_cmp(dhparams_priv, dhparams_peer, 1);
157	0	if (!ret)
158	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISMATCHING_DOMAIN_PARAMETERS);
159	0	return ret;
160	0	}
161
162		static int dh_set_peer(void vpdhctx, void vdh)
163	0	{
164	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
165
166	0	if (!ossl_prov_is_running()
167	0	\|\| pdhctx == NULL
168	0	\|\| vdh == NULL
169	0	\|\| !dh_match_params(vdh, pdhctx->dh)
170	0	\|\| !DH_up_ref(vdh))
171	0	return 0;
172	0	DH_free(pdhctx->dhpeer);
173	0	pdhctx->dhpeer = vdh;
174	0	return 1;
175	0	}
176
177		static int dh_plain_derive(void *vpdhctx,
178		unsigned char secret, size_t secretlen,
179		size_t outlen, unsigned int pad)
180	0	{
181	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
182	0	int ret;
183	0	size_t dhsize;
184	0	const BIGNUM *pub_key = NULL;
185
186	0	if (pdhctx->dh == NULL \|\| pdhctx->dhpeer == NULL) {
187	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
188	0	return 0;
189	0	}
190
191	0	dhsize = (size_t)DH_size(pdhctx->dh);
192	0	if (secret == NULL) {
193	0	*secretlen = dhsize;
194	0	return 1;
195	0	}
196	0	if (outlen < dhsize) {
197	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
198	0	return 0;
199	0	}
200
201	0	DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
202	0	if (pad)
203	0	ret = DH_compute_key_padded(secret, pub_key, pdhctx->dh);
204	0	else
205	0	ret = DH_compute_key(secret, pub_key, pdhctx->dh);
206	0	if (ret <= 0)
207	0	return 0;
208
209	0	*secretlen = ret;
210	0	return 1;
211	0	}
212
213		static int dh_X9_42_kdf_derive(void vpdhctx, unsigned char secret,
214		size_t *secretlen, size_t outlen)
215	0	{
216	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
217	0	unsigned char *stmp = NULL;
218	0	size_t stmplen;
219	0	int ret = 0;
220
221	0	if (secret == NULL) {
222	0	*secretlen = pdhctx->kdf_outlen;
223	0	return 1;
224	0	}
225
226	0	if (pdhctx->kdf_outlen > outlen) {
227	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
228	0	return 0;
229	0	}
230	0	if (!dh_plain_derive(pdhctx, NULL, &stmplen, 0, 1))
231	0	return 0;
232	0	if ((stmp = OPENSSL_secure_malloc(stmplen)) == NULL)
233	0	return 0;
234	0	if (!dh_plain_derive(pdhctx, stmp, &stmplen, stmplen, 1))
235	0	goto err;
236
237		/* Do KDF stuff */
238	0	if (pdhctx->kdf_type == PROV_DH_KDF_X9_42_ASN1) {
239	0	if (!ossl_dh_kdf_X9_42_asn1(secret, pdhctx->kdf_outlen,
240	0	stmp, stmplen,
241	0	pdhctx->kdf_cekalg,
242	0	pdhctx->kdf_ukm,
243	0	pdhctx->kdf_ukmlen,
244	0	pdhctx->kdf_md,
245	0	pdhctx->libctx, NULL))
246	0	goto err;
247	0	}
248	0	*secretlen = pdhctx->kdf_outlen;
249	0	ret = 1;
250	0	err:
251	0	OPENSSL_secure_clear_free(stmp, stmplen);
252	0	return ret;
253	0	}
254
255		static int dh_derive(void vpdhctx, unsigned char secret,
256		size_t *psecretlen, size_t outlen)
257	0	{
258	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
259
260	0	if (!ossl_prov_is_running())
261	0	return 0;
262
263	0	switch (pdhctx->kdf_type) {
264	0	case PROV_DH_KDF_NONE:
265	0	return dh_plain_derive(pdhctx, secret, psecretlen, outlen,
266	0	pdhctx->pad);
267	0	case PROV_DH_KDF_X9_42_ASN1:
268	0	return dh_X9_42_kdf_derive(pdhctx, secret, psecretlen, outlen);
269	0	default:
270	0	break;
271	0	}
272	0	return 0;
273	0	}
274
275		static void dh_freectx(void *vpdhctx)
276	0	{
277	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
278
279	0	OPENSSL_free(pdhctx->kdf_cekalg);
280	0	DH_free(pdhctx->dh);
281	0	DH_free(pdhctx->dhpeer);
282	0	EVP_MD_free(pdhctx->kdf_md);
283	0	OPENSSL_clear_free(pdhctx->kdf_ukm, pdhctx->kdf_ukmlen);
284
285	0	OPENSSL_free(pdhctx);
286	0	}
287
288		static void dh_dupctx(void vpdhctx)
289	0	{
290	0	PROV_DH_CTX srcctx = (PROV_DH_CTX )vpdhctx;
291	0	PROV_DH_CTX *dstctx;
292
293	0	if (!ossl_prov_is_running())
294	0	return NULL;
295
296	0	dstctx = OPENSSL_zalloc(sizeof(*srcctx));
297	0	if (dstctx == NULL)
298	0	return NULL;
299
300	0	dstctx = srcctx;
301	0	dstctx->dh = NULL;
302	0	dstctx->dhpeer = NULL;
303	0	dstctx->kdf_md = NULL;
304	0	dstctx->kdf_ukm = NULL;
305	0	dstctx->kdf_cekalg = NULL;
306
307	0	if (srcctx->dh != NULL && !DH_up_ref(srcctx->dh))
308	0	goto err;
309	0	else
310	0	dstctx->dh = srcctx->dh;
311
312	0	if (srcctx->dhpeer != NULL && !DH_up_ref(srcctx->dhpeer))
313	0	goto err;
314	0	else
315	0	dstctx->dhpeer = srcctx->dhpeer;
316
317	0	if (srcctx->kdf_md != NULL && !EVP_MD_up_ref(srcctx->kdf_md))
318	0	goto err;
319	0	else
320	0	dstctx->kdf_md = srcctx->kdf_md;
321
322		/* Duplicate UKM data if present */
323	0	if (srcctx->kdf_ukm != NULL && srcctx->kdf_ukmlen > 0) {
324	0	dstctx->kdf_ukm = OPENSSL_memdup(srcctx->kdf_ukm,
325	0	srcctx->kdf_ukmlen);
326	0	if (dstctx->kdf_ukm == NULL)
327	0	goto err;
328	0	}
329
330	0	if (srcctx->kdf_cekalg != NULL) {
331	0	dstctx->kdf_cekalg = OPENSSL_strdup(srcctx->kdf_cekalg);
332	0	if (dstctx->kdf_cekalg == NULL)
333	0	goto err;
334	0	}
335
336	0	return dstctx;
337	0	err:
338	0	dh_freectx(dstctx);
339	0	return NULL;
340	0	}
341
342		static int dh_set_ctx_params(void *vpdhctx, const OSSL_PARAM params[])
343	0	{
344	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
345	0	struct dh_set_ctx_params_st p;
346	0	unsigned int pad;
347	0	char name[80] = { '\0' }; /* should be big enough */
348	0	char *str = NULL;
349
350	0	if (pdhctx == NULL \|\| !dh_set_ctx_params_decoder(params, &p))
351	0	return 0;
352
353	0	if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(pdhctx, OSSL_FIPS_IND_SETTABLE0, p.ind_k))
354	0	return 0;
355	0	if (!OSSL_FIPS_IND_SET_CTX_FROM_PARAM(pdhctx, OSSL_FIPS_IND_SETTABLE1, p.ind_d))
356	0	return 0;
357
358	0	if (p.kdf != NULL) {
359	0	str = name;
360	0	if (!OSSL_PARAM_get_utf8_string(p.kdf, &str, sizeof(name)))
361	0	return 0;
362
363	0	if (name[0] == '\0')
364	0	pdhctx->kdf_type = PROV_DH_KDF_NONE;
365	0	else if (strcmp(name, OSSL_KDF_NAME_X942KDF_ASN1) == 0)
366	0	pdhctx->kdf_type = PROV_DH_KDF_X9_42_ASN1;
367	0	else
368	0	return 0;
369	0	}
370
371	0	if (p.digest != NULL) {
372	0	char mdprops[80] = { '\0' }; /* should be big enough */
373
374	0	str = name;
375	0	if (!OSSL_PARAM_get_utf8_string(p.digest, &str, sizeof(name)))
376	0	return 0;
377
378	0	str = mdprops;
379	0	if (p.propq != NULL) {
380	0	if (!OSSL_PARAM_get_utf8_string(p.propq, &str, sizeof(mdprops)))
381	0	return 0;
382	0	}
383
384	0	EVP_MD_free(pdhctx->kdf_md);
385	0	pdhctx->kdf_md = EVP_MD_fetch(pdhctx->libctx, name, mdprops);
386	0	if (pdhctx->kdf_md == NULL)
387	0	return 0;
388		/* XOF digests are not allowed */
389	0	if (EVP_MD_xof(pdhctx->kdf_md)) {
390	0	ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
391	0	return 0;
392	0	}
393		#ifdef FIPS_MODULE
394		if (!digest_check(pdhctx, pdhctx->kdf_md)) {
395		EVP_MD_free(pdhctx->kdf_md);
396		pdhctx->kdf_md = NULL;
397		return 0;
398		}
399		#endif
400	0	}
401
402	0	if (p.len != NULL) {
403	0	size_t outlen;
404
405	0	if (!OSSL_PARAM_get_size_t(p.len, &outlen))
406	0	return 0;
407	0	pdhctx->kdf_outlen = outlen;
408	0	}
409
410	0	if (p.ukm != NULL) {
411	0	void *tmp_ukm = NULL;
412	0	size_t tmp_ukmlen;
413
414	0	OPENSSL_free(pdhctx->kdf_ukm);
415	0	pdhctx->kdf_ukm = NULL;
416	0	pdhctx->kdf_ukmlen = 0;
417		/* ukm is an optional field so it can be NULL */
418	0	if (p.ukm->data != NULL && p.ukm->data_size != 0) {
419	0	if (!OSSL_PARAM_get_octet_string(p.ukm, &tmp_ukm, 0, &tmp_ukmlen))
420	0	return 0;
421	0	pdhctx->kdf_ukm = tmp_ukm;
422	0	pdhctx->kdf_ukmlen = tmp_ukmlen;
423	0	}
424	0	}
425
426	0	if (p.pad != NULL) {
427	0	if (!OSSL_PARAM_get_uint(p.pad, &pad))
428	0	return 0;
429	0	pdhctx->pad = pad ? 1 : 0;
430	0	}
431
432	0	if (p.cekalg != NULL) {
433	0	str = name;
434
435	0	OPENSSL_free(pdhctx->kdf_cekalg);
436	0	pdhctx->kdf_cekalg = NULL;
437	0	if (p.cekalg->data != NULL && p.cekalg->data_size != 0) {
438	0	if (!OSSL_PARAM_get_utf8_string(p.cekalg, &str, sizeof(name)))
439	0	return 0;
440	0	pdhctx->kdf_cekalg = OPENSSL_strdup(name);
441	0	if (pdhctx->kdf_cekalg == NULL)
442	0	return 0;
443	0	}
444	0	}
445	0	return 1;
446	0	}
447
448		static const OSSL_PARAM dh_settable_ctx_params(ossl_unused void vpdhctx,
449		ossl_unused void *provctx)
450	0	{
451	0	return dh_set_ctx_params_list;
452	0	}
453
454		static const OSSL_PARAM dh_gettable_ctx_params(ossl_unused void vpdhctx,
455		ossl_unused void *provctx)
456	0	{
457	0	return dh_get_ctx_params_list;
458	0	}
459
460		static int dh_get_ctx_params(void *vpdhctx, OSSL_PARAM params[])
461	0	{
462	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
463	0	struct dh_get_ctx_params_st p;
464
465	0	if (pdhctx == NULL \|\| !dh_get_ctx_params_decoder(params, &p))
466	0	return 0;
467
468	0	if (p.kdf != NULL) {
469	0	const char *kdf_type = NULL;
470
471	0	switch (pdhctx->kdf_type) {
472	0	case PROV_DH_KDF_NONE:
473	0	kdf_type = "";
474	0	break;
475	0	case PROV_DH_KDF_X9_42_ASN1:
476	0	kdf_type = OSSL_KDF_NAME_X942KDF_ASN1;
477	0	break;
478	0	default:
479	0	return 0;
480	0	}
481
482	0	if (!OSSL_PARAM_set_utf8_string(p.kdf, kdf_type))
483	0	return 0;
484	0	}
485
486	0	if (p.digest != NULL
487	0	&& !OSSL_PARAM_set_utf8_string(p.digest, pdhctx->kdf_md == NULL
488	0	? ""
489	0	: EVP_MD_get0_name(pdhctx->kdf_md))) {
490	0	return 0;
491	0	}
492
493	0	if (p.len != NULL && !OSSL_PARAM_set_size_t(p.len, pdhctx->kdf_outlen))
494	0	return 0;
495
496	0	if (p.ukm != NULL
497	0	&& !OSSL_PARAM_set_octet_ptr(p.ukm, pdhctx->kdf_ukm, pdhctx->kdf_ukmlen))
498	0	return 0;
499
500	0	if (p.cekalg != NULL
501	0	&& !OSSL_PARAM_set_utf8_string(p.cekalg, pdhctx->kdf_cekalg == NULL
502	0	? "" : pdhctx->kdf_cekalg))
503	0	return 0;
504
505	0	if (!OSSL_FIPS_IND_GET_CTX_FROM_PARAM(pdhctx, p.ind))
506	0	return 0;
507	0	return 1;
508	0	}
509
510		const OSSL_DISPATCH ossl_dh_keyexch_functions[] = {
511		{ OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
512		{ OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
513		{ OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
514		{ OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
515		{ OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
516		{ OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
517		{ OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))dh_set_ctx_params },
518		{ OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS,
519		(void (*)(void))dh_settable_ctx_params },
520		{ OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS, (void (*)(void))dh_get_ctx_params },
521		{ OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS,
522		(void (*)(void))dh_gettable_ctx_params },
523		OSSL_DISPATCH_END
524		};