2 * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.
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
11 * DH low level APIs are deprecated for public use, but still ok for
14 #include "internal/deprecated.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"
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;
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".
53 PROV_DH_KDF_X9_42_ASN1
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.
69 /* KDF (if any) to use for DH */
70 enum kdf_type kdf_type;
71 /* Message digest to use for key derivation */
73 /* User key material */
74 unsigned char *kdf_ukm;
76 /* KDF output length */
81 static void *dh_newctx(void *provctx)
85 if (!ossl_prov_is_running())
88 pdhctx = OPENSSL_zalloc(sizeof(PROV_DH_CTX));
91 pdhctx->libctx = PROV_LIBCTX_OF(provctx);
92 pdhctx->kdf_type = PROV_DH_KDF_NONE;
96 static int dh_init(void *vpdhctx, void *vdh, const OSSL_PARAM params[])
98 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
100 if (!ossl_prov_is_running()
107 pdhctx->kdf_type = PROV_DH_KDF_NONE;
108 return dh_set_ctx_params(pdhctx, params)
109 && ossl_dh_check_key(pdhctx->libctx, vdh);
112 /* The 2 parties must share the same domain parameters */
113 static int dh_match_params(DH *priv, DH *peer)
116 FFC_PARAMS *dhparams_priv = ossl_dh_get0_params(priv);
117 FFC_PARAMS *dhparams_peer = ossl_dh_get0_params(peer);
119 ret = dhparams_priv != NULL
120 && dhparams_peer != NULL
121 && ossl_ffc_params_cmp(dhparams_priv, dhparams_peer, 1);
123 ERR_raise(ERR_LIB_PROV, PROV_R_MISMATCHING_DOMAIN_PARAMETERS);
127 static int dh_set_peer(void *vpdhctx, void *vdh)
129 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
131 if (!ossl_prov_is_running()
134 || !dh_match_params(vdh, pdhctx->dh)
137 DH_free(pdhctx->dhpeer);
138 pdhctx->dhpeer = vdh;
142 static int dh_plain_derive(void *vpdhctx,
143 unsigned char *secret, size_t *secretlen,
144 size_t outlen, unsigned int pad)
146 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
149 const BIGNUM *pub_key = NULL;
151 if (pdhctx->dh == NULL || pdhctx->dhpeer == NULL) {
152 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
156 dhsize = (size_t)DH_size(pdhctx->dh);
157 if (secret == NULL) {
161 if (outlen < dhsize) {
162 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
166 DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
168 ret = DH_compute_key_padded(secret, pub_key, pdhctx->dh);
170 ret = DH_compute_key(secret, pub_key, pdhctx->dh);
178 static int dh_X9_42_kdf_derive(void *vpdhctx, unsigned char *secret,
179 size_t *secretlen, size_t outlen)
181 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
182 unsigned char *stmp = NULL;
186 if (secret == NULL) {
187 *secretlen = pdhctx->kdf_outlen;
191 if (pdhctx->kdf_outlen > outlen) {
192 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
195 if (!dh_plain_derive(pdhctx, NULL, &stmplen, 0, 1))
197 if ((stmp = OPENSSL_secure_malloc(stmplen)) == NULL)
199 if (!dh_plain_derive(pdhctx, stmp, &stmplen, stmplen, 1))
203 if (pdhctx->kdf_type == PROV_DH_KDF_X9_42_ASN1) {
204 if (!ossl_dh_kdf_X9_42_asn1(secret, pdhctx->kdf_outlen,
210 pdhctx->libctx, NULL))
213 *secretlen = pdhctx->kdf_outlen;
216 OPENSSL_secure_clear_free(stmp, stmplen);
220 static int dh_derive(void *vpdhctx, unsigned char *secret,
221 size_t *psecretlen, size_t outlen)
223 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
225 if (!ossl_prov_is_running())
228 switch (pdhctx->kdf_type) {
229 case PROV_DH_KDF_NONE:
230 return dh_plain_derive(pdhctx, secret, psecretlen, outlen,
232 case PROV_DH_KDF_X9_42_ASN1:
233 return dh_X9_42_kdf_derive(pdhctx, secret, psecretlen, outlen);
240 static void dh_freectx(void *vpdhctx)
242 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
244 OPENSSL_free(pdhctx->kdf_cekalg);
246 DH_free(pdhctx->dhpeer);
247 EVP_MD_free(pdhctx->kdf_md);
248 OPENSSL_clear_free(pdhctx->kdf_ukm, pdhctx->kdf_ukmlen);
250 OPENSSL_free(pdhctx);
253 static void *dh_dupctx(void *vpdhctx)
255 PROV_DH_CTX *srcctx = (PROV_DH_CTX *)vpdhctx;
258 if (!ossl_prov_is_running())
261 dstctx = OPENSSL_zalloc(sizeof(*srcctx));
267 dstctx->dhpeer = NULL;
268 dstctx->kdf_md = NULL;
269 dstctx->kdf_ukm = NULL;
270 dstctx->kdf_cekalg = NULL;
272 if (srcctx->dh != NULL && !DH_up_ref(srcctx->dh))
275 dstctx->dh = srcctx->dh;
277 if (srcctx->dhpeer != NULL && !DH_up_ref(srcctx->dhpeer))
280 dstctx->dhpeer = srcctx->dhpeer;
282 if (srcctx->kdf_md != NULL && !EVP_MD_up_ref(srcctx->kdf_md))
285 dstctx->kdf_md = srcctx->kdf_md;
287 /* Duplicate UKM data if present */
288 if (srcctx->kdf_ukm != NULL && srcctx->kdf_ukmlen > 0) {
289 dstctx->kdf_ukm = OPENSSL_memdup(srcctx->kdf_ukm,
291 if (dstctx->kdf_ukm == NULL)
295 if (srcctx->kdf_cekalg != NULL) {
296 dstctx->kdf_cekalg = OPENSSL_strdup(srcctx->kdf_cekalg);
297 if (dstctx->kdf_cekalg == NULL)
307 static int dh_set_ctx_params(void *vpdhctx, const OSSL_PARAM params[])
309 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
312 char name[80] = { '\0' }; /* should be big enough */
320 p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
323 if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
327 pdhctx->kdf_type = PROV_DH_KDF_NONE;
328 else if (strcmp(name, OSSL_KDF_NAME_X942KDF_ASN1) == 0)
329 pdhctx->kdf_type = PROV_DH_KDF_X9_42_ASN1;
333 p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST);
335 char mdprops[80] = { '\0' }; /* should be big enough */
338 if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
342 p = OSSL_PARAM_locate_const(params,
343 OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS);
346 if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(mdprops)))
350 EVP_MD_free(pdhctx->kdf_md);
351 pdhctx->kdf_md = EVP_MD_fetch(pdhctx->libctx, name, mdprops);
352 if (pdhctx->kdf_md == NULL)
354 if (!ossl_digest_is_allowed(pdhctx->libctx, pdhctx->kdf_md)) {
355 EVP_MD_free(pdhctx->kdf_md);
356 pdhctx->kdf_md = NULL;
361 p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
365 if (!OSSL_PARAM_get_size_t(p, &outlen))
367 pdhctx->kdf_outlen = outlen;
370 p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
372 void *tmp_ukm = NULL;
375 OPENSSL_free(pdhctx->kdf_ukm);
376 pdhctx->kdf_ukm = NULL;
377 pdhctx->kdf_ukmlen = 0;
378 /* ukm is an optional field so it can be NULL */
379 if (p->data != NULL && p->data_size != 0) {
380 if (!OSSL_PARAM_get_octet_string(p, &tmp_ukm, 0, &tmp_ukmlen))
382 pdhctx->kdf_ukm = tmp_ukm;
383 pdhctx->kdf_ukmlen = tmp_ukmlen;
387 p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_PAD);
389 if (!OSSL_PARAM_get_uint(p, &pad))
391 pdhctx->pad = pad ? 1 : 0;
394 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG);
398 OPENSSL_free(pdhctx->kdf_cekalg);
399 pdhctx->kdf_cekalg = NULL;
400 if (p->data != NULL && p->data_size != 0) {
401 if (!OSSL_PARAM_get_utf8_string(p, &str, sizeof(name)))
403 pdhctx->kdf_cekalg = OPENSSL_strdup(name);
404 if (pdhctx->kdf_cekalg == NULL)
411 static const OSSL_PARAM known_settable_ctx_params[] = {
412 OSSL_PARAM_int(OSSL_EXCHANGE_PARAM_PAD, NULL),
413 OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
414 OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
415 OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS, NULL, 0),
416 OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
417 OSSL_PARAM_octet_string(OSSL_EXCHANGE_PARAM_KDF_UKM, NULL, 0),
418 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
422 static const OSSL_PARAM *dh_settable_ctx_params(ossl_unused void *vpdhctx,
423 ossl_unused void *provctx)
425 return known_settable_ctx_params;
428 static const OSSL_PARAM known_gettable_ctx_params[] = {
429 OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_TYPE, NULL, 0),
430 OSSL_PARAM_utf8_string(OSSL_EXCHANGE_PARAM_KDF_DIGEST, NULL, 0),
431 OSSL_PARAM_size_t(OSSL_EXCHANGE_PARAM_KDF_OUTLEN, NULL),
432 OSSL_PARAM_DEFN(OSSL_EXCHANGE_PARAM_KDF_UKM, OSSL_PARAM_OCTET_PTR,
434 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
438 static const OSSL_PARAM *dh_gettable_ctx_params(ossl_unused void *vpdhctx,
439 ossl_unused void *provctx)
441 return known_gettable_ctx_params;
444 static int dh_get_ctx_params(void *vpdhctx, OSSL_PARAM params[])
446 PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
452 p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_TYPE);
454 const char *kdf_type = NULL;
456 switch (pdhctx->kdf_type) {
457 case PROV_DH_KDF_NONE:
460 case PROV_DH_KDF_X9_42_ASN1:
461 kdf_type = OSSL_KDF_NAME_X942KDF_ASN1;
467 if (!OSSL_PARAM_set_utf8_string(p, kdf_type))
471 p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_DIGEST);
473 && !OSSL_PARAM_set_utf8_string(p, pdhctx->kdf_md == NULL
475 : EVP_MD_get0_name(pdhctx->kdf_md))) {
479 p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_OUTLEN);
480 if (p != NULL && !OSSL_PARAM_set_size_t(p, pdhctx->kdf_outlen))
483 p = OSSL_PARAM_locate(params, OSSL_EXCHANGE_PARAM_KDF_UKM);
485 && !OSSL_PARAM_set_octet_ptr(p, pdhctx->kdf_ukm, pdhctx->kdf_ukmlen))
488 p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_CEK_ALG);
490 && !OSSL_PARAM_set_utf8_string(p, pdhctx->kdf_cekalg == NULL
491 ? "" : pdhctx->kdf_cekalg))
497 const OSSL_DISPATCH ossl_dh_keyexch_functions[] = {
498 { OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
499 { OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
500 { OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
501 { OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
502 { OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
503 { OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
504 { OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS, (void (*)(void))dh_set_ctx_params },
505 { OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS,
506 (void (*)(void))dh_settable_ctx_params },
507 { OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS, (void (*)(void))dh_get_ctx_params },
508 { OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS,
509 (void (*)(void))dh_gettable_ctx_params },