2 * Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
11 #include "internal/e_os.h"
12 #include <openssl/core_names.h>
13 #include <openssl/core_dispatch.h>
14 #include <openssl/err.h>
15 #include <openssl/evp.h>
16 #include <openssl/params.h>
17 #include <openssl/proverr.h>
18 #include "internal/packet.h"
19 #include "internal/der.h"
20 #include "prov/provider_ctx.h"
21 #include "prov/providercommon.h"
22 #include "prov/implementations.h"
23 #include "prov/provider_util.h"
24 #include "prov/der_wrap.h"
26 #define X942KDF_MAX_INLEN (1 << 30)
28 static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
29 static OSSL_FUNC_kdf_dupctx_fn x942kdf_dup;
30 static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
31 static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
32 static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
33 static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
34 static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
35 static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
36 static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;
41 unsigned char *secret;
43 unsigned char *acvpinfo;
45 unsigned char *partyuinfo, *partyvinfo, *supp_pubinfo, *supp_privinfo;
46 size_t partyuinfo_len, partyvinfo_len, supp_pubinfo_len, supp_privinfo_len;
48 const unsigned char *cek_oid;
54 * A table of allowed wrapping algorithms, oids and the associated output
56 * NOTE: RC2wrap and camellia128_wrap have been removed as there are no
57 * corresponding ciphers for these operations.
61 const unsigned char *oid;
63 size_t keklen; /* size in bytes */
65 { "AES-128-WRAP", ossl_der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap,
67 { "AES-192-WRAP", ossl_der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap,
69 { "AES-256-WRAP", ossl_der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap,
72 { "DES3-WRAP", ossl_der_oid_id_alg_CMS3DESwrap,
73 DER_OID_SZ_id_alg_CMS3DESwrap, 24 },
77 static int find_alg_id(OSSL_LIB_CTX *libctx, const char *algname,
78 const char *propq, size_t *id)
84 cipher = EVP_CIPHER_fetch(libctx, algname, propq);
86 for (i = 0; i < OSSL_NELEM(kek_algs); i++) {
87 if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {
94 ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
96 EVP_CIPHER_free(cipher);
100 static int DER_w_keyinfo(WPACKET *pkt,
101 const unsigned char *der_oid, size_t der_oidlen,
102 unsigned char **pcounter)
104 return ossl_DER_w_begin_sequence(pkt, -1)
105 /* Store the initial value of 1 into the counter */
106 && ossl_DER_w_octet_string_uint32(pkt, -1, 1)
107 /* Remember where we stored the counter in the buffer */
109 || (*pcounter = WPACKET_get_curr(pkt)) != NULL)
110 && ossl_DER_w_precompiled(pkt, -1, der_oid, der_oidlen)
111 && ossl_DER_w_end_sequence(pkt, -1);
114 static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,
115 const unsigned char *der_oid, size_t der_oidlen,
116 const unsigned char *acvp, size_t acvplen,
117 const unsigned char *partyu, size_t partyulen,
118 const unsigned char *partyv, size_t partyvlen,
119 const unsigned char *supp_pub, size_t supp_publen,
120 const unsigned char *supp_priv, size_t supp_privlen,
121 uint32_t keylen_bits, unsigned char **pcounter)
123 return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) :
124 WPACKET_init_null_der(pkt))
125 && ossl_DER_w_begin_sequence(pkt, -1)
126 && (supp_priv == NULL
127 || ossl_DER_w_octet_string(pkt, 3, supp_priv, supp_privlen))
129 || ossl_DER_w_octet_string(pkt, 2, supp_pub, supp_publen))
131 || ossl_DER_w_octet_string_uint32(pkt, 2, keylen_bits))
132 && (partyv == NULL || ossl_DER_w_octet_string(pkt, 1, partyv, partyvlen))
133 && (partyu == NULL || ossl_DER_w_octet_string(pkt, 0, partyu, partyulen))
134 && (acvp == NULL || ossl_DER_w_precompiled(pkt, -1, acvp, acvplen))
135 && DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)
136 && ossl_DER_w_end_sequence(pkt, -1)
137 && WPACKET_finish(pkt);
141 * Encode the other info structure.
143 * The ANS X9.42-2003 standard uses OtherInfo:
145 * OtherInfo ::= SEQUENCE {
146 * keyInfo KeySpecificInfo,
147 * partyUInfo [0] OCTET STRING OPTIONAL,
148 * partyVInfo [1] OCTET STRING OPTIONAL,
149 * suppPubInfo [2] OCTET STRING OPTIONAL,
150 * suppPrivInfo [3] OCTET STRING OPTIONAL
153 * KeySpecificInfo ::= SEQUENCE {
154 * algorithm OBJECT IDENTIFIER,
155 * counter OCTET STRING SIZE (4..4)
158 * RFC2631 Section 2.1.2 Contains the following definition for OtherInfo
160 * OtherInfo ::= SEQUENCE {
161 * keyInfo KeySpecificInfo,
162 * partyAInfo [0] OCTET STRING OPTIONAL,
163 * suppPubInfo [2] OCTET STRING
165 * Where suppPubInfo is the key length (in bits) (stored into 4 bytes)
167 * |keylen| is the length (in bytes) of the generated KEK. It is stored into
168 * suppPubInfo (in bits). It is ignored if the value is 0.
169 * |cek_oid| The oid of the key wrapping algorithm.
170 * |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,
171 * |acvp| is the optional blob of DER data representing one or more of the
172 * OtherInfo fields related to |partyu|, |partyv|, |supp_pub| and |supp_priv|.
173 * This field should normally be NULL. If |acvp| is non NULL then |partyu|,
174 * |partyv|, |supp_pub| and |supp_priv| should all be NULL.
175 * |acvp_len| is the |acvp| length (in bytes).
176 * |partyu| is the optional public info contributed by the initiator.
177 * It can be NULL. (It is also used as the ukm by CMS).
178 * |partyu_len| is the |partyu| length (in bytes).
179 * |partyv| is the optional public info contributed by the responder.
181 * |partyv_len| is the |partyv| length (in bytes).
182 * |supp_pub| is the optional additional, mutually-known public information.
183 * It can be NULL. |keylen| should be 0 if this is not NULL.
184 * |supp_pub_len| is the |supp_pub| length (in bytes).
185 * |supp_priv| is the optional additional, mutually-known private information.
187 * |supp_priv_len| is the |supp_priv| length (in bytes).
188 * |der| is the returned encoded data. It must be freed by the caller.
189 * |der_len| is the returned size of the encoded data.
190 * |out_ctr| returns a pointer to the counter data which is embedded inside the
191 * encoded data. This allows the counter bytes to be updated without
194 * Returns: 1 if successfully encoded, or 0 otherwise.
195 * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
198 x942_encode_otherinfo(size_t keylen,
199 const unsigned char *cek_oid, size_t cek_oid_len,
200 const unsigned char *acvp, size_t acvp_len,
201 const unsigned char *partyu, size_t partyu_len,
202 const unsigned char *partyv, size_t partyv_len,
203 const unsigned char *supp_pub, size_t supp_pub_len,
204 const unsigned char *supp_priv, size_t supp_priv_len,
205 unsigned char **der, size_t *der_len,
206 unsigned char **out_ctr)
209 unsigned char *pcounter = NULL, *der_buf = NULL;
210 size_t der_buflen = 0;
212 uint32_t keylen_bits;
214 /* keylenbits must fit into 4 bytes */
215 if (keylen > 0xFFFFFF)
217 keylen_bits = 8 * keylen;
219 /* Calculate the size of the buffer */
220 if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oid_len,
222 partyu, partyu_len, partyv, partyv_len,
223 supp_pub, supp_pub_len, supp_priv, supp_priv_len,
225 || !WPACKET_get_total_written(&pkt, &der_buflen))
227 WPACKET_cleanup(&pkt);
228 /* Alloc the buffer */
229 der_buf = OPENSSL_zalloc(der_buflen);
232 /* Encode into the buffer */
233 if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oid_len,
235 partyu, partyu_len, partyv, partyv_len,
236 supp_pub, supp_pub_len, supp_priv, supp_priv_len,
237 keylen_bits, &pcounter))
240 * Since we allocated the exact size required, the buffer should point to the
241 * start of the alllocated buffer at this point.
243 if (WPACKET_get_curr(&pkt) != der_buf)
247 * The data for the DER encoded octet string of a 32 bit counter = 1
248 * should be 04 04 00 00 00 01
249 * So just check the header is correct and skip over it.
250 * This counter will be incremented in the kdf update loop.
253 || pcounter[0] != 0x04
254 || pcounter[1] != 0x04)
256 *out_ctr = (pcounter + 2);
258 *der_len = der_buflen;
261 WPACKET_cleanup(&pkt);
265 static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
266 const unsigned char *z, size_t z_len,
267 const unsigned char *other, size_t other_len,
269 unsigned char *derived_key, size_t derived_key_len)
272 size_t counter, out_len, len = derived_key_len;
273 unsigned char mac[EVP_MAX_MD_SIZE];
274 unsigned char *out = derived_key;
275 EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
277 if (z_len > X942KDF_MAX_INLEN
278 || other_len > X942KDF_MAX_INLEN
279 || derived_key_len > X942KDF_MAX_INLEN
280 || derived_key_len == 0) {
281 ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
285 hlen = EVP_MD_get_size(kdf_md);
288 out_len = (size_t)hlen;
290 ctx = EVP_MD_CTX_create();
291 ctx_init = EVP_MD_CTX_create();
292 if (ctx == NULL || ctx_init == NULL)
295 if (!EVP_DigestInit(ctx_init, kdf_md))
298 for (counter = 1;; counter++) {
299 /* updating the ctr modifies 4 bytes in the 'other' buffer */
300 ctr[0] = (unsigned char)((counter >> 24) & 0xff);
301 ctr[1] = (unsigned char)((counter >> 16) & 0xff);
302 ctr[2] = (unsigned char)((counter >> 8) & 0xff);
303 ctr[3] = (unsigned char)(counter & 0xff);
305 if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
306 || !EVP_DigestUpdate(ctx, z, z_len)
307 || !EVP_DigestUpdate(ctx, other, other_len))
309 if (len >= out_len) {
310 if (!EVP_DigestFinal_ex(ctx, out, NULL))
317 if (!EVP_DigestFinal_ex(ctx, mac, NULL))
319 memcpy(out, mac, len);
325 EVP_MD_CTX_free(ctx);
326 EVP_MD_CTX_free(ctx_init);
327 OPENSSL_cleanse(mac, sizeof(mac));
331 static void *x942kdf_new(void *provctx)
335 if (!ossl_prov_is_running())
338 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
339 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
340 ctx->provctx = provctx;
341 ctx->use_keybits = 1;
345 static void x942kdf_reset(void *vctx)
347 KDF_X942 *ctx = (KDF_X942 *)vctx;
348 void *provctx = ctx->provctx;
350 ossl_prov_digest_reset(&ctx->digest);
351 OPENSSL_clear_free(ctx->secret, ctx->secret_len);
352 OPENSSL_clear_free(ctx->acvpinfo, ctx->acvpinfo_len);
353 OPENSSL_clear_free(ctx->partyuinfo, ctx->partyuinfo_len);
354 OPENSSL_clear_free(ctx->partyvinfo, ctx->partyvinfo_len);
355 OPENSSL_clear_free(ctx->supp_pubinfo, ctx->supp_pubinfo_len);
356 OPENSSL_clear_free(ctx->supp_privinfo, ctx->supp_privinfo_len);
357 memset(ctx, 0, sizeof(*ctx));
358 ctx->provctx = provctx;
359 ctx->use_keybits = 1;
362 static void x942kdf_free(void *vctx)
364 KDF_X942 *ctx = (KDF_X942 *)vctx;
372 static void *x942kdf_dup(void *vctx)
374 const KDF_X942 *src = (const KDF_X942 *)vctx;
377 dest = x942kdf_new(src->provctx);
379 if (!ossl_prov_memdup(src->secret, src->secret_len,
380 &dest->secret , &dest->secret_len)
381 || !ossl_prov_memdup(src->acvpinfo, src->acvpinfo_len,
382 &dest->acvpinfo , &dest->acvpinfo_len)
383 || !ossl_prov_memdup(src->partyuinfo, src->partyuinfo_len,
384 &dest->partyuinfo , &dest->partyuinfo_len)
385 || !ossl_prov_memdup(src->partyvinfo, src->partyvinfo_len,
386 &dest->partyvinfo , &dest->partyvinfo_len)
387 || !ossl_prov_memdup(src->supp_pubinfo, src->supp_pubinfo_len,
389 &dest->supp_pubinfo_len)
390 || !ossl_prov_memdup(src->supp_privinfo, src->supp_privinfo_len,
391 &dest->supp_privinfo,
392 &dest->supp_privinfo_len)
393 || !ossl_prov_digest_copy(&dest->digest, &src->digest))
395 dest->cek_oid = src->cek_oid;
396 dest->cek_oid_len = src->cek_oid_len;
397 dest->dkm_len = src->dkm_len;
398 dest->use_keybits = src->use_keybits;
407 static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,
410 if (p->data_size == 0 || p->data == NULL)
415 return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
418 static size_t x942kdf_size(KDF_X942 *ctx)
421 const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
424 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
427 len = EVP_MD_get_size(md);
428 return (len <= 0) ? 0 : (size_t)len;
431 static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen,
432 const OSSL_PARAM params[])
434 KDF_X942 *ctx = (KDF_X942 *)vctx;
438 unsigned char *der = NULL;
441 if (!ossl_prov_is_running() || !x942kdf_set_ctx_params(ctx, params))
445 * These 2 options encode to the same field so only one of them should be
448 if (ctx->use_keybits && ctx->supp_pubinfo != NULL) {
449 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_PUBINFO);
453 * If the blob of acvp data is used then the individual info fields that it
454 * replaces should not also be defined.
456 if (ctx->acvpinfo != NULL
457 && (ctx->partyuinfo != NULL
458 || ctx->partyvinfo != NULL
459 || ctx->supp_pubinfo != NULL
460 || ctx->supp_privinfo != NULL)) {
461 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DATA);
464 if (ctx->secret == NULL) {
465 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
468 md = ossl_prov_digest_md(&ctx->digest);
470 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
473 if (ctx->cek_oid == NULL || ctx->cek_oid_len == 0) {
474 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
477 if (ctx->partyuinfo != NULL && ctx->partyuinfo_len >= X942KDF_MAX_INLEN) {
479 * Note the ukm length MUST be 512 bits if it is used.
480 * For backwards compatibility the old check is being done.
482 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_UKM_LENGTH);
485 /* generate the otherinfo der */
486 if (!x942_encode_otherinfo(ctx->use_keybits ? ctx->dkm_len : 0,
487 ctx->cek_oid, ctx->cek_oid_len,
488 ctx->acvpinfo, ctx->acvpinfo_len,
489 ctx->partyuinfo, ctx->partyuinfo_len,
490 ctx->partyvinfo, ctx->partyvinfo_len,
491 ctx->supp_pubinfo, ctx->supp_pubinfo_len,
492 ctx->supp_privinfo, ctx->supp_privinfo_len,
493 &der, &der_len, &ctr)) {
494 ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);
497 ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,
498 der, der_len, ctr, key, keylen);
503 static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
505 const OSSL_PARAM *p, *pq;
506 KDF_X942 *ctx = vctx;
507 OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
508 const char *propq = NULL;
513 if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
516 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET);
518 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);
519 if (p != NULL && !x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
522 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_ACVPINFO);
524 && !x942kdf_set_buffer(&ctx->acvpinfo, &ctx->acvpinfo_len, p))
527 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_PARTYUINFO);
529 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM);
531 && !x942kdf_set_buffer(&ctx->partyuinfo, &ctx->partyuinfo_len, p))
534 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_PARTYVINFO);
536 && !x942kdf_set_buffer(&ctx->partyvinfo, &ctx->partyvinfo_len, p))
539 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_USE_KEYBITS);
540 if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_keybits))
543 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_SUPP_PUBINFO);
545 if (!x942kdf_set_buffer(&ctx->supp_pubinfo, &ctx->supp_pubinfo_len, p))
547 ctx->use_keybits = 0;
550 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_SUPP_PRIVINFO);
552 && !x942kdf_set_buffer(&ctx->supp_privinfo, &ctx->supp_privinfo_len, p))
555 p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG);
557 if (p->data_type != OSSL_PARAM_UTF8_STRING)
559 pq = OSSL_PARAM_locate_const(params, OSSL_ALG_PARAM_PROPERTIES);
561 * We already grab the properties during ossl_prov_digest_load_from_params()
562 * so there is no need to check the validity again..
566 if (find_alg_id(provctx, p->data, propq, &id) == 0)
568 ctx->cek_oid = kek_algs[id].oid;
569 ctx->cek_oid_len = kek_algs[id].oid_len;
570 ctx->dkm_len = kek_algs[id].keklen;
575 static const OSSL_PARAM *x942kdf_settable_ctx_params(ossl_unused void *ctx,
576 ossl_unused void *provctx)
578 static const OSSL_PARAM known_settable_ctx_params[] = {
579 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
580 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
581 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
582 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
583 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),
584 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_ACVPINFO, NULL, 0),
585 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_PARTYUINFO, NULL, 0),
586 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_PARTYVINFO, NULL, 0),
587 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_SUPP_PUBINFO, NULL, 0),
588 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_SUPP_PRIVINFO, NULL, 0),
589 OSSL_PARAM_int(OSSL_KDF_PARAM_X942_USE_KEYBITS, NULL),
590 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
593 return known_settable_ctx_params;
596 static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
598 KDF_X942 *ctx = (KDF_X942 *)vctx;
601 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
602 return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));
606 static const OSSL_PARAM *x942kdf_gettable_ctx_params(ossl_unused void *ctx,
607 ossl_unused void *provctx)
609 static const OSSL_PARAM known_gettable_ctx_params[] = {
610 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
613 return known_gettable_ctx_params;
616 const OSSL_DISPATCH ossl_kdf_x942_kdf_functions[] = {
617 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))x942kdf_new },
618 { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))x942kdf_dup },
619 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))x942kdf_free },
620 { OSSL_FUNC_KDF_RESET, (void(*)(void))x942kdf_reset },
621 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x942kdf_derive },
622 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
623 (void(*)(void))x942kdf_settable_ctx_params },
624 { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))x942kdf_set_ctx_params },
625 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
626 (void(*)(void))x942kdf_gettable_ctx_params },
627 { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))x942kdf_get_ctx_params },