providers/implementations/kdfs/scrypt.c

   1 /*
   2  * Copyright 2017-2022 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/err.h>
  16 #include <openssl/core_names.h>
  17 #include <openssl/proverr.h>
  18 #include "crypto/evp.h"
  19 #include "internal/numbers.h"
  20 #include "prov/implementations.h"
  21 #include "prov/provider_ctx.h"
  22 #include "prov/providercommon.h"
  23 #include "prov/provider_util.h"
  24
  25 #ifndef OPENSSL_NO_SCRYPT
  26
  27 static OSSL_FUNC_kdf_newctx_fn kdf_scrypt_new;
  28 static OSSL_FUNC_kdf_dupctx_fn kdf_scrypt_dup;
  29 static OSSL_FUNC_kdf_freectx_fn kdf_scrypt_free;
  30 static OSSL_FUNC_kdf_reset_fn kdf_scrypt_reset;
  31 static OSSL_FUNC_kdf_derive_fn kdf_scrypt_derive;
  32 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
  33 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_scrypt_set_ctx_params;
  34 static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_scrypt_gettable_ctx_params;
  35 static OSSL_FUNC_kdf_get_ctx_params_fn kdf_scrypt_get_ctx_params;
  36
  37 static int scrypt_alg(const char *pass, size_t passlen,
  38                       const unsigned char *salt, size_t saltlen,
  39                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
  40                       unsigned char *key, size_t keylen, EVP_MD *sha256,
  41                       OSSL_LIB_CTX *libctx, const char *propq);
  42
  43 typedef struct {
  44     OSSL_LIB_CTX *libctx;
  45     char *propq;
  46     unsigned char *pass;
  47     size_t pass_len;
  48     unsigned char *salt;
  49     size_t salt_len;
  50     uint64_t N;
  51     uint64_t r, p;
  52     uint64_t maxmem_bytes;
  53     EVP_MD *sha256;
  54 } KDF_SCRYPT;
  55
  56 static void kdf_scrypt_init(KDF_SCRYPT *ctx);
  57
  58 static void *kdf_scrypt_new_inner(OSSL_LIB_CTX *libctx)
  59 {
  60     KDF_SCRYPT *ctx;
  61
  62     if (!ossl_prov_is_running())
  63         return NULL;
  64
  65     ctx = OPENSSL_zalloc(sizeof(*ctx));
  66     if (ctx == NULL) {
  67         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
  68         return NULL;
  69     }
  70     ctx->libctx = libctx;
  71     kdf_scrypt_init(ctx);
  72     return ctx;
  73 }
  74
  75 static void *kdf_scrypt_new(void *provctx)
  76 {
  77     return kdf_scrypt_new_inner(PROV_LIBCTX_OF(provctx));
  78 }
  79
  80 static void kdf_scrypt_free(void *vctx)
  81 {
  82     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  83
  84     if (ctx != NULL) {
  85         OPENSSL_free(ctx->propq);
  86         EVP_MD_free(ctx->sha256);
  87         kdf_scrypt_reset(ctx);
  88         OPENSSL_free(ctx);
  89     }
  90 }
  91
  92 static void kdf_scrypt_reset(void *vctx)
  93 {
  94     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  95
  96     OPENSSL_free(ctx->salt);
  97     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  98     kdf_scrypt_init(ctx);
  99 }
 100
 101 static void *kdf_scrypt_dup(void *vctx)
 102 {
 103     const KDF_SCRYPT *src = (const KDF_SCRYPT *)vctx;
 104     KDF_SCRYPT *dest;
 105
 106     dest = kdf_scrypt_new_inner(src->libctx);
 107     if (dest != NULL) {
 108         if (src->sha256 != NULL && !EVP_MD_up_ref(src->sha256))
 109             goto err;
 110         if (src->propq != NULL) {
 111             dest->propq = OPENSSL_strdup(src->propq);
 112             if (dest->propq == NULL)
 113                 goto err;
 114         }
 115         if (!ossl_prov_memdup(src->salt, src->salt_len,
 116                               &dest->salt, &dest->salt_len)
 117                 || !ossl_prov_memdup(src->pass, src->pass_len,
 118                                      &dest->pass , &dest->pass_len))
 119             goto err;
 120         dest->N = src->N;
 121         dest->r = src->r;
 122         dest->p = src->p;
 123         dest->maxmem_bytes = src->maxmem_bytes;
 124         dest->sha256 = src->sha256;
 125     }
 126     return dest;
 127
 128  err:
 129     kdf_scrypt_free(dest);
 130     return NULL;
 131 }
 132
 133 static void kdf_scrypt_init(KDF_SCRYPT *ctx)
 134 {
 135     /* Default values are the most conservative recommendation given in the
 136      * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
 137      * for this parameter choice (approx. 128 * r * N * p bytes).
 138      */
 139     ctx->N = 1 << 20;
 140     ctx->r = 8;
 141     ctx->p = 1;
 142     ctx->maxmem_bytes = 1025 * 1024 * 1024;
 143 }
 144
 145 static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
 146                              const OSSL_PARAM *p)
 147 {
 148     OPENSSL_clear_free(*buffer, *buflen);
 149     *buffer = NULL;
 150     *buflen = 0;
 151
 152     if (p->data_size == 0) {
 153         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 154             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 155             return 0;
 156         }
 157     } else if (p->data != NULL) {
 158         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 159             return 0;
 160     }
 161     return 1;
 162 }
 163
 164 static int set_digest(KDF_SCRYPT *ctx)
 165 {
 166     EVP_MD_free(ctx->sha256);
 167     ctx->sha256 = EVP_MD_fetch(ctx->libctx, "sha256", ctx->propq);
 168     if (ctx->sha256 == NULL) {
 169         OPENSSL_free(ctx);
 170         ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
 171         return 0;
 172     }
 173     return 1;
 174 }
 175
 176 static int set_property_query(KDF_SCRYPT *ctx, const char *propq)
 177 {
 178     OPENSSL_free(ctx->propq);
 179     ctx->propq = NULL;
 180     if (propq != NULL) {
 181         ctx->propq = OPENSSL_strdup(propq);
 182         if (ctx->propq == NULL) {
 183             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 184             return 0;
 185         }
 186     }
 187     return 1;
 188 }
 189
 190 static int kdf_scrypt_derive(void *vctx, unsigned char *key, size_t keylen,
 191                              const OSSL_PARAM params[])
 192 {
 193     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
 194
 195     if (!ossl_prov_is_running() || !kdf_scrypt_set_ctx_params(ctx, params))
 196         return 0;
 197
 198     if (ctx->pass == NULL) {
 199         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 200         return 0;
 201     }
 202
 203     if (ctx->salt == NULL) {
 204         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 205         return 0;
 206     }
 207
 208     if (ctx->sha256 == NULL && !set_digest(ctx))
 209         return 0;
 210
 211     return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
 212                       ctx->salt_len, ctx->N, ctx->r, ctx->p,
 213                       ctx->maxmem_bytes, key, keylen, ctx->sha256,
 214                       ctx->libctx, ctx->propq);
 215 }
 216
 217 static int is_power_of_two(uint64_t value)
 218 {
 219     return (value != 0) && ((value & (value - 1)) == 0);
 220 }
 221
 222 static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 223 {
 224     const OSSL_PARAM *p;
 225     KDF_SCRYPT *ctx = vctx;
 226     uint64_t u64_value;
 227
 228     if (params == NULL)
 229         return 1;
 230
 231     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 232         if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
 233             return 0;
 234
 235     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 236         if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
 237             return 0;
 238
 239     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
 240         != NULL) {
 241         if (!OSSL_PARAM_get_uint64(p, &u64_value)
 242             || u64_value <= 1
 243             || !is_power_of_two(u64_value))
 244             return 0;
 245         ctx->N = u64_value;
 246     }
 247
 248     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
 249         != NULL) {
 250         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 251             return 0;
 252         ctx->r = u64_value;
 253     }
 254
 255     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
 256         != NULL) {
 257         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 258             return 0;
 259         ctx->p = u64_value;
 260     }
 261
 262     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
 263         != NULL) {
 264         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 265             return 0;
 266         ctx->maxmem_bytes = u64_value;
 267     }
 268
 269     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES);
 270     if (p != NULL) {
 271         if (p->data_type != OSSL_PARAM_UTF8_STRING
 272             || !set_property_query(ctx, p->data)
 273             || !set_digest(ctx))
 274             return 0;
 275     }
 276     return 1;
 277 }
 278
 279 static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(ossl_unused void *ctx,
 280                                                         ossl_unused void *p_ctx)
 281 {
 282     static const OSSL_PARAM known_settable_ctx_params[] = {
 283         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 284         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 285         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
 286         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
 287         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
 288         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
 289         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 290         OSSL_PARAM_END
 291     };
 292     return known_settable_ctx_params;
 293 }
 294
 295 static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
 296 {
 297     OSSL_PARAM *p;
 298
 299     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 300         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 301     return -2;
 302 }
 303
 304 static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(ossl_unused void *ctx,
 305                                                         ossl_unused void *p_ctx)
 306 {
 307     static const OSSL_PARAM known_gettable_ctx_params[] = {
 308         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 309         OSSL_PARAM_END
 310     };
 311     return known_gettable_ctx_params;
 312 }
 313
 314 const OSSL_DISPATCH ossl_kdf_scrypt_functions[] = {
 315     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
 316     { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_scrypt_dup },
 317     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
 318     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
 319     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
 320     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 321       (void(*)(void))kdf_scrypt_settable_ctx_params },
 322     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
 323     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 324       (void(*)(void))kdf_scrypt_gettable_ctx_params },
 325     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
 326     { 0, NULL }
 327 };
 328
 329 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
 330 static void salsa208_word_specification(uint32_t inout[16])
 331 {
 332     int i;
 333     uint32_t x[16];
 334
 335     memcpy(x, inout, sizeof(x));
 336     for (i = 8; i > 0; i -= 2) {
 337         x[4] ^= R(x[0] + x[12], 7);
 338         x[8] ^= R(x[4] + x[0], 9);
 339         x[12] ^= R(x[8] + x[4], 13);
 340         x[0] ^= R(x[12] + x[8], 18);
 341         x[9] ^= R(x[5] + x[1], 7);
 342         x[13] ^= R(x[9] + x[5], 9);
 343         x[1] ^= R(x[13] + x[9], 13);
 344         x[5] ^= R(x[1] + x[13], 18);
 345         x[14] ^= R(x[10] + x[6], 7);
 346         x[2] ^= R(x[14] + x[10], 9);
 347         x[6] ^= R(x[2] + x[14], 13);
 348         x[10] ^= R(x[6] + x[2], 18);
 349         x[3] ^= R(x[15] + x[11], 7);
 350         x[7] ^= R(x[3] + x[15], 9);
 351         x[11] ^= R(x[7] + x[3], 13);
 352         x[15] ^= R(x[11] + x[7], 18);
 353         x[1] ^= R(x[0] + x[3], 7);
 354         x[2] ^= R(x[1] + x[0], 9);
 355         x[3] ^= R(x[2] + x[1], 13);
 356         x[0] ^= R(x[3] + x[2], 18);
 357         x[6] ^= R(x[5] + x[4], 7);
 358         x[7] ^= R(x[6] + x[5], 9);
 359         x[4] ^= R(x[7] + x[6], 13);
 360         x[5] ^= R(x[4] + x[7], 18);
 361         x[11] ^= R(x[10] + x[9], 7);
 362         x[8] ^= R(x[11] + x[10], 9);
 363         x[9] ^= R(x[8] + x[11], 13);
 364         x[10] ^= R(x[9] + x[8], 18);
 365         x[12] ^= R(x[15] + x[14], 7);
 366         x[13] ^= R(x[12] + x[15], 9);
 367         x[14] ^= R(x[13] + x[12], 13);
 368         x[15] ^= R(x[14] + x[13], 18);
 369     }
 370     for (i = 0; i < 16; ++i)
 371         inout[i] += x[i];
 372     OPENSSL_cleanse(x, sizeof(x));
 373 }
 374
 375 static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
 376 {
 377     uint64_t i, j;
 378     uint32_t X[16], *pB;
 379
 380     memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
 381     pB = B;
 382     for (i = 0; i < r * 2; i++) {
 383         for (j = 0; j < 16; j++)
 384             X[j] ^= *pB++;
 385         salsa208_word_specification(X);
 386         memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
 387     }
 388     OPENSSL_cleanse(X, sizeof(X));
 389 }
 390
 391 static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
 392                         uint32_t *X, uint32_t *T, uint32_t *V)
 393 {
 394     unsigned char *pB;
 395     uint32_t *pV;
 396     uint64_t i, k;
 397
 398     /* Convert from little endian input */
 399     for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
 400         *pV = *pB++;
 401         *pV |= *pB++ << 8;
 402         *pV |= *pB++ << 16;
 403         *pV |= (uint32_t)*pB++ << 24;
 404     }
 405
 406     for (i = 1; i < N; i++, pV += 32 * r)
 407         scryptBlockMix(pV, pV - 32 * r, r);
 408
 409     scryptBlockMix(X, V + (N - 1) * 32 * r, r);
 410
 411     for (i = 0; i < N; i++) {
 412         uint32_t j;
 413         j = X[16 * (2 * r - 1)] % N;
 414         pV = V + 32 * r * j;
 415         for (k = 0; k < 32 * r; k++)
 416             T[k] = X[k] ^ *pV++;
 417         scryptBlockMix(X, T, r);
 418     }
 419     /* Convert output to little endian */
 420     for (i = 0, pB = B; i < 32 * r; i++) {
 421         uint32_t xtmp = X[i];
 422         *pB++ = xtmp & 0xff;
 423         *pB++ = (xtmp >> 8) & 0xff;
 424         *pB++ = (xtmp >> 16) & 0xff;
 425         *pB++ = (xtmp >> 24) & 0xff;
 426     }
 427 }
 428
 429 #ifndef SIZE_MAX
 430 # define SIZE_MAX    ((size_t)-1)
 431 #endif
 432
 433 /*
 434  * Maximum power of two that will fit in uint64_t: this should work on
 435  * most (all?) platforms.
 436  */
 437
 438 #define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
 439
 440 /*
 441  * Maximum value of p * r:
 442  * p <= ((2^32-1) * hLen) / MFLen =>
 443  * p <= ((2^32-1) * 32) / (128 * r) =>
 444  * p * r <= (2^30-1)
 445  */
 446
 447 #define SCRYPT_PR_MAX   ((1 << 30) - 1)
 448
 449 static int scrypt_alg(const char *pass, size_t passlen,
 450                       const unsigned char *salt, size_t saltlen,
 451                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
 452                       unsigned char *key, size_t keylen, EVP_MD *sha256,
 453                       OSSL_LIB_CTX *libctx, const char *propq)
 454 {
 455     int rv = 0;
 456     unsigned char *B;
 457     uint32_t *X, *V, *T;
 458     uint64_t i, Blen, Vlen;
 459
 460     /* Sanity check parameters */
 461     /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
 462     if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
 463         return 0;
 464     /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
 465     if (p > SCRYPT_PR_MAX / r) {
 466         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 467         return 0;
 468     }
 469
 470     /*
 471      * Need to check N: if 2^(128 * r / 8) overflows limit this is
 472      * automatically satisfied since N <= UINT64_MAX.
 473      */
 474
 475     if (16 * r <= LOG2_UINT64_MAX) {
 476         if (N >= (((uint64_t)1) << (16 * r))) {
 477             ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 478             return 0;
 479         }
 480     }
 481
 482     /* Memory checks: check total allocated buffer size fits in uint64_t */
 483
 484     /*
 485      * B size in section 5 step 1.S
 486      * Note: we know p * 128 * r < UINT64_MAX because we already checked
 487      * p * r < SCRYPT_PR_MAX
 488      */
 489     Blen = p * 128 * r;
 490     /*
 491      * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
 492      * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
 493      */
 494     if (Blen > INT_MAX) {
 495         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 496         return 0;
 497     }
 498
 499     /*
 500      * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
 501      * This is combined size V, X and T (section 4)
 502      */
 503     i = UINT64_MAX / (32 * sizeof(uint32_t));
 504     if (N + 2 > i / r) {
 505         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 506         return 0;
 507     }
 508     Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
 509
 510     /* check total allocated size fits in uint64_t */
 511     if (Blen > UINT64_MAX - Vlen) {
 512         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 513         return 0;
 514     }
 515
 516     /* Check that the maximum memory doesn't exceed a size_t limits */
 517     if (maxmem > SIZE_MAX)
 518         maxmem = SIZE_MAX;
 519
 520     if (Blen + Vlen > maxmem) {
 521         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 522         return 0;
 523     }
 524
 525     /* If no key return to indicate parameters are OK */
 526     if (key == NULL)
 527         return 1;
 528
 529     B = OPENSSL_malloc((size_t)(Blen + Vlen));
 530     if (B == NULL) {
 531         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 532         return 0;
 533     }
 534     X = (uint32_t *)(B + Blen);
 535     T = X + 32 * r;
 536     V = T + 32 * r;
 537     if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, salt, saltlen, 1, sha256,
 538                                   (int)Blen, B, libctx, propq) == 0)
 539         goto err;
 540
 541     for (i = 0; i < p; i++)
 542         scryptROMix(B + 128 * r * i, r, N, X, T, V);
 543
 544     if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, B, (int)Blen, 1, sha256,
 545                                   keylen, key, libctx, propq) == 0)
 546         goto err;
 547     rv = 1;
 548  err:
 549     if (rv == 0)
 550         ERR_raise(ERR_LIB_EVP, EVP_R_PBKDF2_ERROR);
 551
 552     OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
 553     return rv;
 554 }
 555
 556 #endif