/src/openssl30/providers/implementations/exchange/dh_exch.c

Source
/*
 * Copyright 2019-2026 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 "prov/providercommon.h"
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/securitycheck.h"
#include "crypto/dh.h"

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;
} 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;
    pdhctx->libctx = PROV_LIBCTX_OF(provctx);
    pdhctx->kdf_type = PROV_DH_KDF_NONE;
    return pdhctx;
}

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;
    return dh_set_ctx_params(pdhctx, params)
        && ossl_dh_check_key(pdhctx->libctx, vdh);
}

/* The 2 parties must share the same domain parameters */
static int dh_match_params(DH *priv, DH *peer)
{
    int ret;
    int ignore_q = 1;
    FFC_PARAMS *dhparams_priv = ossl_dh_get0_params(priv);
    FFC_PARAMS *dhparams_peer = ossl_dh_get0_params(peer);

    if (dhparams_priv != NULL && dhparams_priv->q != NULL)
        ignore_q = 0;
    ret = dhparams_priv != NULL
        && dhparams_peer != NULL
        && ossl_ffc_params_cmp(dhparams_priv, dhparams_peer, ignore_q);
    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) {
        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
        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;
    const OSSL_PARAM *p;
    unsigned int pad;
    char name[80] = { '\0' }; /* should be big enough */
    char *str = NULL;

    if (pdhctx == NULL)
        return 0;
    if (params == NULL)
        return 1;

    p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
    if (p != NULL) {
        str = name;
        if (!OSSL_PARAM_get_utf8_string(p, &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;
    }
    p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST);
    if (p != NULL) {
        char mdprops[80] = { '\0' }; /* should be big enough */

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

        str = mdprops;
        p = OSSL_PARAM_locate_const(params,
            OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS);

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

        EVP_MD_free(pdhctx->kdf_md);
        pdhctx->kdf_md = EVP_MD_fetch(pdhctx->libctx, name, mdprops);
        if (!ossl_digest_is_allowed(pdhctx->libctx, pdhctx->kdf_md)) {
            EVP_MD_free(pdhctx->kdf_md);
            pdhctx->kdf_md = NULL;
        }
        if (pdhctx->kdf_md == NULL)
            return 0;
    }

    p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
    if (p != NULL) {
        size_t outlen;

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

    p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
    if (p != 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->data != NULL && p->data_size != 0) {
            if (!OSSL_PARAM_get_octet_string(p, &tmp_ukm, 0, &tmp_ukmlen))
                return 0;
            pdhctx->kdf_ukm = tmp_ukm;
            pdhctx->kdf_ukmlen = tmp_ukmlen;
        }
    }

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

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG);
    if (p != NULL) {
        str = name;

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

static const OSSL_PARAM known_settable_ctx_params[] = {
    OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_PAD, NULL),
    OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS, NULL, 0),
    OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
    OSSL_PARAM_octet_string(OSSL_EXCHANGE_PARAM_KDF_UKM, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
    OSSL_PARAM_END
};

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

static const OSSL_PARAM known_gettable_ctx_params[] = {
    OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
    OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
    OSSL_PARAM_DEFN(OSSL_EXCHANGE_PARAM_KDF_UKM, OSSL_PARAM_OCTET_PTR,
        NULL, 0),
    OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
    OSSL_PARAM_END
};

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

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

    if (pdhctx == NULL)
        return 0;

    p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
    if (p != 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_type))
            return 0;
    }

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

    p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
    if (p != NULL && !OSSL_PARAM_set_size_t(p, pdhctx->kdf_outlen))
        return 0;

    p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
    if (p != NULL
        && !OSSL_PARAM_set_octet_ptr(p, pdhctx->kdf_ukm, pdhctx->kdf_ukmlen))
        return 0;

    p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_CEK_ALG);
    if (p != NULL
        && !OSSL_PARAM_set_utf8_string(p, pdhctx->kdf_cekalg == NULL ? "" : pdhctx->kdf_cekalg))
        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 },
    { 0, NULL }
};

Coverage Report

Created: 2026-07-12 07:21

Line	Count	Source
1		/*
2		* Copyright 2019-2026 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 "prov/providercommon.h"
25		#include "prov/implementations.h"
26		#include "prov/provider_ctx.h"
27		#include "prov/securitycheck.h"
28		#include "crypto/dh.h"
29
30		static OSSL_FUNC_keyexch_newctx_fn dh_newctx;
31		static OSSL_FUNC_keyexch_init_fn dh_init;
32		static OSSL_FUNC_keyexch_set_peer_fn dh_set_peer;
33		static OSSL_FUNC_keyexch_derive_fn dh_derive;
34		static OSSL_FUNC_keyexch_freectx_fn dh_freectx;
35		static OSSL_FUNC_keyexch_dupctx_fn dh_dupctx;
36		static OSSL_FUNC_keyexch_set_ctx_params_fn dh_set_ctx_params;
37		static OSSL_FUNC_keyexch_settable_ctx_params_fn dh_settable_ctx_params;
38		static OSSL_FUNC_keyexch_get_ctx_params_fn dh_get_ctx_params;
39		static OSSL_FUNC_keyexch_gettable_ctx_params_fn dh_gettable_ctx_params;
40
41		/*
42		* This type is only really used to handle some legacy related functionality.
43		* If you need to use other KDF's (such as SSKDF) just use PROV_DH_KDF_NONE
44		* here and then create and run a KDF after the key is derived.
45		* Note that X942 has 2 variants of key derivation:
46		* (1) DH_KDF_X9_42_ASN1 - which contains an ANS1 encoded object that has
47		* the counter embedded in it.
48		* (2) DH_KDF_X941_CONCAT - which is the same as ECDH_X963_KDF (which can be
49		* done by creating a "X963KDF".
50		*/
51		enum kdf_type {
52		PROV_DH_KDF_NONE = 0,
53		PROV_DH_KDF_X9_42_ASN1
54		};
55
56		/*
57		* What's passed as an actual key is defined by the KEYMGMT interface.
58		* We happen to know that our KEYMGMT simply passes DH structures, so
59		* we use that here too.
60		*/
61
62		typedef struct {
63		OSSL_LIB_CTX *libctx;
64		DH *dh;
65		DH *dhpeer;
66		unsigned int pad : 1;
67
68		/* DH KDF */
69		/* KDF (if any) to use for DH */
70		enum kdf_type kdf_type;
71		/* Message digest to use for key derivation */
72		EVP_MD *kdf_md;
73		/* User key material */
74		unsigned char *kdf_ukm;
75		size_t kdf_ukmlen;
76		/* KDF output length */
77		size_t kdf_outlen;
78		char *kdf_cekalg;
79		} PROV_DH_CTX;
80
81		static void dh_newctx(void provctx)
82	4.78k	{
83	4.78k	PROV_DH_CTX *pdhctx;
84
85	4.78k	if (!ossl_prov_is_running())
86	0	return NULL;
87
88	4.78k	pdhctx = OPENSSL_zalloc(sizeof(PROV_DH_CTX));
89	4.78k	if (pdhctx == NULL)
90	0	return NULL;
91	4.78k	pdhctx->libctx = PROV_LIBCTX_OF(provctx);
92	4.78k	pdhctx->kdf_type = PROV_DH_KDF_NONE;
93	4.78k	return pdhctx;
94	4.78k	}
95
96		static int dh_init(void vpdhctx, void vdh, const OSSL_PARAM params[])
97	1.87k	{
98	1.87k	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
99
100	1.87k	if (!ossl_prov_is_running()
101	1.87k	\|\| pdhctx == NULL
102	1.87k	\|\| vdh == NULL
103	1.87k	\|\| !DH_up_ref(vdh))
104	0	return 0;
105	1.87k	DH_free(pdhctx->dh);
106	1.87k	pdhctx->dh = vdh;
107	1.87k	pdhctx->kdf_type = PROV_DH_KDF_NONE;
108	1.87k	return dh_set_ctx_params(pdhctx, params)
109	1.87k	&& ossl_dh_check_key(pdhctx->libctx, vdh);
110	1.87k	}
111
112		/* The 2 parties must share the same domain parameters */
113		static int dh_match_params(DH priv, DH peer)
114	3.57k	{
115	3.57k	int ret;
116	3.57k	int ignore_q = 1;
117	3.57k	FFC_PARAMS *dhparams_priv = ossl_dh_get0_params(priv);
118	3.57k	FFC_PARAMS *dhparams_peer = ossl_dh_get0_params(peer);
119
120	3.57k	if (dhparams_priv != NULL && dhparams_priv->q != NULL)
121	524	ignore_q = 0;
122	3.57k	ret = dhparams_priv != NULL
123	3.57k	&& dhparams_peer != NULL
124	3.57k	&& ossl_ffc_params_cmp(dhparams_priv, dhparams_peer, ignore_q);
125	3.57k	if (!ret)
126	3.57k	ERR_raise(ERR_LIB_PROV, PROV_R_MISMATCHING_DOMAIN_PARAMETERS);
127	3.57k	return ret;
128	3.57k	}
129
130		static int dh_set_peer(void vpdhctx, void vdh)
131	4.47k	{
132	4.47k	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
133
134	4.47k	if (!ossl_prov_is_running()
135	4.47k	\|\| pdhctx == NULL
136	4.47k	\|\| vdh == NULL
137	4.47k	\|\| !dh_match_params(vdh, pdhctx->dh)
138	4.47k	\|\| !DH_up_ref(vdh))
139	0	return 0;
140	4.47k	DH_free(pdhctx->dhpeer);
141	4.47k	pdhctx->dhpeer = vdh;
142	4.47k	return 1;
143	4.47k	}
144
145		static int dh_plain_derive(void *vpdhctx,
146		unsigned char secret, size_t secretlen,
147		size_t outlen, unsigned int pad)
148	8.95k	{
149	8.95k	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
150	8.95k	int ret;
151	8.95k	size_t dhsize;
152	8.95k	const BIGNUM *pub_key = NULL;
153
154	8.95k	if (pdhctx->dh == NULL \|\| pdhctx->dhpeer == NULL) {
155	0	ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
156	0	return 0;
157	0	}
158
159	8.95k	dhsize = (size_t)DH_size(pdhctx->dh);
160	8.95k	if (secret == NULL) {
161	4.47k	*secretlen = dhsize;
162	4.47k	return 1;
163	4.47k	}
164	4.47k	if (outlen < dhsize) {
165	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
166	0	return 0;
167	0	}
168
169	4.47k	DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
170	4.47k	if (pad)
171	120	ret = DH_compute_key_padded(secret, pub_key, pdhctx->dh);
172	4.35k	else
173	4.35k	ret = DH_compute_key(secret, pub_key, pdhctx->dh);
174	4.47k	if (ret <= 0)
175	0	return 0;
176
177	4.47k	*secretlen = ret;
178	4.47k	return 1;
179	4.47k	}
180
181		static int dh_X9_42_kdf_derive(void vpdhctx, unsigned char secret,
182		size_t *secretlen, size_t outlen)
183	0	{
184	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
185	0	unsigned char *stmp = NULL;
186	0	size_t stmplen;
187	0	int ret = 0;
188
189	0	if (secret == NULL) {
190	0	*secretlen = pdhctx->kdf_outlen;
191	0	return 1;
192	0	}
193
194	0	if (pdhctx->kdf_outlen > outlen) {
195	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
196	0	return 0;
197	0	}
198	0	if (!dh_plain_derive(pdhctx, NULL, &stmplen, 0, 1))
199	0	return 0;
200	0	if ((stmp = OPENSSL_secure_malloc(stmplen)) == NULL) {
201	0	ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
202	0	return 0;
203	0	}
204	0	if (!dh_plain_derive(pdhctx, stmp, &stmplen, stmplen, 1))
205	0	goto err;
206
207		/* Do KDF stuff */
208	0	if (pdhctx->kdf_type == PROV_DH_KDF_X9_42_ASN1) {
209	0	if (!ossl_dh_kdf_X9_42_asn1(secret, pdhctx->kdf_outlen,
210	0	stmp, stmplen,
211	0	pdhctx->kdf_cekalg,
212	0	pdhctx->kdf_ukm,
213	0	pdhctx->kdf_ukmlen,
214	0	pdhctx->kdf_md,
215	0	pdhctx->libctx, NULL))
216	0	goto err;
217	0	}
218	0	*secretlen = pdhctx->kdf_outlen;
219	0	ret = 1;
220	0	err:
221	0	OPENSSL_secure_clear_free(stmp, stmplen);
222	0	return ret;
223	0	}
224
225		static int dh_derive(void vpdhctx, unsigned char secret,
226		size_t *psecretlen, size_t outlen)
227	8.95k	{
228	8.95k	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
229
230	8.95k	if (!ossl_prov_is_running())
231	0	return 0;
232
233	8.95k	switch (pdhctx->kdf_type) {
234	8.95k	case PROV_DH_KDF_NONE:
235	8.95k	return dh_plain_derive(pdhctx, secret, psecretlen, outlen,
236	8.95k	pdhctx->pad);
237	0	case PROV_DH_KDF_X9_42_ASN1:
238	0	return dh_X9_42_kdf_derive(pdhctx, secret, psecretlen, outlen);
239	0	default:
240	0	break;
241	8.95k	}
242	0	return 0;
243	8.95k	}
244
245		static void dh_freectx(void *vpdhctx)
246	4.78k	{
247	4.78k	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
248
249	4.78k	OPENSSL_free(pdhctx->kdf_cekalg);
250	4.78k	DH_free(pdhctx->dh);
251	4.78k	DH_free(pdhctx->dhpeer);
252	4.78k	EVP_MD_free(pdhctx->kdf_md);
253	4.78k	OPENSSL_clear_free(pdhctx->kdf_ukm, pdhctx->kdf_ukmlen);
254
255	4.78k	OPENSSL_free(pdhctx);
256	4.78k	}
257
258		static void dh_dupctx(void vpdhctx)
259	0	{
260	0	PROV_DH_CTX srcctx = (PROV_DH_CTX )vpdhctx;
261	0	PROV_DH_CTX *dstctx;
262
263	0	if (!ossl_prov_is_running())
264	0	return NULL;
265
266	0	dstctx = OPENSSL_zalloc(sizeof(*srcctx));
267	0	if (dstctx == NULL)
268	0	return NULL;
269
270	0	dstctx = srcctx;
271	0	dstctx->dh = NULL;
272	0	dstctx->dhpeer = NULL;
273	0	dstctx->kdf_md = NULL;
274	0	dstctx->kdf_ukm = NULL;
275	0	dstctx->kdf_cekalg = NULL;
276
277	0	if (srcctx->dh != NULL && !DH_up_ref(srcctx->dh))
278	0	goto err;
279	0	else
280	0	dstctx->dh = srcctx->dh;
281
282	0	if (srcctx->dhpeer != NULL && !DH_up_ref(srcctx->dhpeer))
283	0	goto err;
284	0	else
285	0	dstctx->dhpeer = srcctx->dhpeer;
286
287	0	if (srcctx->kdf_md != NULL && !EVP_MD_up_ref(srcctx->kdf_md))
288	0	goto err;
289	0	else
290	0	dstctx->kdf_md = srcctx->kdf_md;
291
292		/* Duplicate UKM data if present */
293	0	if (srcctx->kdf_ukm != NULL && srcctx->kdf_ukmlen > 0) {
294	0	dstctx->kdf_ukm = OPENSSL_memdup(srcctx->kdf_ukm,
295	0	srcctx->kdf_ukmlen);
296	0	if (dstctx->kdf_ukm == NULL)
297	0	goto err;
298	0	}
299
300	0	if (srcctx->kdf_cekalg != NULL) {
301	0	dstctx->kdf_cekalg = OPENSSL_strdup(srcctx->kdf_cekalg);
302	0	if (dstctx->kdf_cekalg == NULL)
303	0	goto err;
304	0	}
305
306	0	return dstctx;
307	0	err:
308	0	dh_freectx(dstctx);
309	0	return NULL;
310	0	}
311
312		static int dh_set_ctx_params(void *vpdhctx, const OSSL_PARAM params[])
313	762	{
314	762	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
315	762	const OSSL_PARAM *p;
316	762	unsigned int pad;
317	762	char name[80] = { '\0' }; /* should be big enough */
318	762	char *str = NULL;
319
320	762	if (pdhctx == NULL)
321	0	return 0;
322	762	if (params == NULL)
323	762	return 1;
324
325	0	p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
326	0	if (p != NULL) {
327	0	str = name;
328	0	if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
329	0	return 0;
330
331	0	if (name[0] == '\0')
332	0	pdhctx->kdf_type = PROV_DH_KDF_NONE;
333	0	else if (strcmp(name, OSSL_KDF_NAME_X942KDF_ASN1) == 0)
334	0	pdhctx->kdf_type = PROV_DH_KDF_X9_42_ASN1;
335	0	else
336	0	return 0;
337	0	}
338	0	p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST);
339	0	if (p != NULL) {
340	0	char mdprops[80] = { '\0' }; /* should be big enough */
341
342	0	str = name;
343	0	if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
344	0	return 0;
345
346	0	str = mdprops;
347	0	p = OSSL_PARAM_locate_const(params,
348	0	OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS);
349
350	0	if (p != NULL) {
351	0	if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(mdprops)))
352	0	return 0;
353	0	}
354
355	0	EVP_MD_free(pdhctx->kdf_md);
356	0	pdhctx->kdf_md = EVP_MD_fetch(pdhctx->libctx, name, mdprops);
357	0	if (!ossl_digest_is_allowed(pdhctx->libctx, pdhctx->kdf_md)) {
358	0	EVP_MD_free(pdhctx->kdf_md);
359	0	pdhctx->kdf_md = NULL;
360	0	}
361	0	if (pdhctx->kdf_md == NULL)
362	0	return 0;
363	0	}
364
365	0	p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
366	0	if (p != NULL) {
367	0	size_t outlen;
368
369	0	if (!OSSL_PARAM_get_size_t(p, &outlen))
370	0	return 0;
371	0	pdhctx->kdf_outlen = outlen;
372	0	}
373
374	0	p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
375	0	if (p != NULL) {
376	0	void *tmp_ukm = NULL;
377	0	size_t tmp_ukmlen;
378
379	0	OPENSSL_free(pdhctx->kdf_ukm);
380	0	pdhctx->kdf_ukm = NULL;
381	0	pdhctx->kdf_ukmlen = 0;
382		/* ukm is an optional field so it can be NULL */
383	0	if (p->data != NULL && p->data_size != 0) {
384	0	if (!OSSL_PARAM_get_octet_string(p, &tmp_ukm, 0, &tmp_ukmlen))
385	0	return 0;
386	0	pdhctx->kdf_ukm = tmp_ukm;
387	0	pdhctx->kdf_ukmlen = tmp_ukmlen;
388	0	}
389	0	}
390
391	0	p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_PAD);
392	0	if (p != NULL) {
393	0	if (!OSSL_PARAM_get_uint(p, &pad))
394	0	return 0;
395	0	pdhctx->pad = pad ? 1 : 0;
396	0	}
397
398	0	p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG);
399	0	if (p != NULL) {
400	0	str = name;
401
402	0	OPENSSL_free(pdhctx->kdf_cekalg);
403	0	pdhctx->kdf_cekalg = NULL;
404	0	if (p->data != NULL && p->data_size != 0) {
405	0	if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
406	0	return 0;
407	0	pdhctx->kdf_cekalg = OPENSSL_strdup(name);
408	0	if (pdhctx->kdf_cekalg == NULL)
409	0	return 0;
410	0	}
411	0	}
412	0	return 1;
413	0	}
414
415		static const OSSL_PARAM known_settable_ctx_params[] = {
416		OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_PAD, NULL),
417		OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
418		OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
419		OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS, NULL, 0),
420		OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
421		OSSL_PARAM_octet_string(OSSL_EXCHANGE_PARAM_KDF_UKM, NULL, 0),
422		OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
423		OSSL_PARAM_END
424		};
425
426		static const OSSL_PARAM dh_settable_ctx_params(ossl_unused void vpdhctx,
427		ossl_unused void *provctx)
428	137	{
429	137	return known_settable_ctx_params;
430	137	}
431
432		static const OSSL_PARAM known_gettable_ctx_params[] = {
433		OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
434		OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
435		OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
436		OSSL_PARAM_DEFN(OSSL_EXCHANGE_PARAM_KDF_UKM, OSSL_PARAM_OCTET_PTR,
437		NULL, 0),
438		OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
439		OSSL_PARAM_END
440		};
441
442		static const OSSL_PARAM dh_gettable_ctx_params(ossl_unused void vpdhctx,
443		ossl_unused void *provctx)
444	0	{
445	0	return known_gettable_ctx_params;
446	0	}
447
448		static int dh_get_ctx_params(void *vpdhctx, OSSL_PARAM params[])
449	0	{
450	0	PROV_DH_CTX pdhctx = (PROV_DH_CTX )vpdhctx;
451	0	OSSL_PARAM *p;
452
453	0	if (pdhctx == NULL)
454	0	return 0;
455
456	0	p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
457	0	if (p != NULL) {
458	0	const char *kdf_type = NULL;
459
460	0	switch (pdhctx->kdf_type) {
461	0	case PROV_DH_KDF_NONE:
462	0	kdf_type = "";
463	0	break;
464	0	case PROV_DH_KDF_X9_42_ASN1:
465	0	kdf_type = OSSL_KDF_NAME_X942KDF_ASN1;
466	0	break;
467	0	default:
468	0	return 0;
469	0	}
470
471	0	if (!OSSL_PARAM_set_utf8_string(p, kdf_type))
472	0	return 0;
473	0	}
474
475	0	p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST);
476	0	if (p != NULL
477	0	&& !OSSL_PARAM_set_utf8_string(p, pdhctx->kdf_md == NULL ? "" : EVP_MD_get0_name(pdhctx->kdf_md))) {
478	0	return 0;
479	0	}
480
481	0	p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
482	0	if (p != NULL && !OSSL_PARAM_set_size_t(p, pdhctx->kdf_outlen))
483	0	return 0;
484
485	0	p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
486	0	if (p != NULL
487	0	&& !OSSL_PARAM_set_octet_ptr(p, pdhctx->kdf_ukm, pdhctx->kdf_ukmlen))
488	0	return 0;
489
490	0	p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_CEK_ALG);
491	0	if (p != NULL
492	0	&& !OSSL_PARAM_set_utf8_string(p, pdhctx->kdf_cekalg == NULL ? "" : pdhctx->kdf_cekalg))
493	0	return 0;
494
495	0	return 1;
496	0	}
497
498		const OSSL_DISPATCH ossl_dh_keyexch_functions[] = {
499		{ OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
500		{ OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
501		{ OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
502		{ OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
503		{ OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
504		{ OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
505		{ OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))dh_set_ctx_params },
506		{ OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS,
507		(void (*)(void))dh_settable_ctx_params },
508		{ OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS, (void (*)(void))dh_get_ctx_params },
509		{ OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS,
510		(void (*)(void))dh_gettable_ctx_params },
511		{ 0, NULL }
512		};