providers/implementations/kdfs/scrypt.c

   1 /*
   2  * Copyright 2017-2021 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/implementations.h"
  24
  25 #ifndef OPENSSL_NO_SCRYPT
  26
  27 static OSSL_FUNC_kdf_newctx_fn kdf_scrypt_new;
  28 static OSSL_FUNC_kdf_freectx_fn kdf_scrypt_free;
  29 static OSSL_FUNC_kdf_reset_fn kdf_scrypt_reset;
  30 static OSSL_FUNC_kdf_derive_fn kdf_scrypt_derive;
  31 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
  32 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_scrypt_set_ctx_params;
  33 static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_scrypt_gettable_ctx_params;
  34 static OSSL_FUNC_kdf_get_ctx_params_fn kdf_scrypt_get_ctx_params;
  35
  36 static int scrypt_alg(const char *pass, size_t passlen,
  37                       const unsigned char *salt, size_t saltlen,
  38                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
  39                       unsigned char *key, size_t keylen, EVP_MD *sha256,
  40                       OSSL_LIB_CTX *libctx, const char *propq);
  41
  42 typedef struct {
  43     OSSL_LIB_CTX *libctx;
  44     char *propq;
  45     unsigned char *pass;
  46     size_t pass_len;
  47     unsigned char *salt;
  48     size_t salt_len;
  49     uint64_t N;
  50     uint64_t r, p;
  51     uint64_t maxmem_bytes;
  52     EVP_MD *sha256;
  53 } KDF_SCRYPT;
  54
  55 static void kdf_scrypt_init(KDF_SCRYPT *ctx);
  56
  57 static void *kdf_scrypt_new(void *provctx)
  58 {
  59     KDF_SCRYPT *ctx;
  60
  61     if (!ossl_prov_is_running())
  62         return NULL;
  63
  64     ctx = OPENSSL_zalloc(sizeof(*ctx));
  65     if (ctx == NULL) {
  66         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
  67         return NULL;
  68     }
  69     ctx->libctx = PROV_LIBCTX_OF(provctx);
  70     kdf_scrypt_init(ctx);
  71     return ctx;
  72 }
  73
  74 static void kdf_scrypt_free(void *vctx)
  75 {
  76     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  77
  78     if (ctx != NULL) {
  79         OPENSSL_free(ctx->propq);
  80         EVP_MD_free(ctx->sha256);
  81         kdf_scrypt_reset(ctx);
  82         OPENSSL_free(ctx);
  83     }
  84 }
  85
  86 static void kdf_scrypt_reset(void *vctx)
  87 {
  88     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  89
  90     OPENSSL_free(ctx->salt);
  91     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  92     kdf_scrypt_init(ctx);
  93 }
  94
  95 static void kdf_scrypt_init(KDF_SCRYPT *ctx)
  96 {
  97     /* Default values are the most conservative recommendation given in the
  98      * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
  99      * for this parameter choice (approx. 128 * r * N * p bytes).
 100      */
 101     ctx->N = 1 << 20;
 102     ctx->r = 8;
 103     ctx->p = 1;
 104     ctx->maxmem_bytes = 1025 * 1024 * 1024;
 105 }
 106
 107 static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
 108                              const OSSL_PARAM *p)
 109 {
 110     OPENSSL_clear_free(*buffer, *buflen);
 111     if (p->data_size == 0) {
 112         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 113             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 114             return 0;
 115         }
 116     } else if (p->data != NULL) {
 117         *buffer = NULL;
 118         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 119             return 0;
 120     }
 121     return 1;
 122 }
 123
 124 static int set_digest(KDF_SCRYPT *ctx)
 125 {
 126     EVP_MD_free(ctx->sha256);
 127     ctx->sha256 = EVP_MD_fetch(ctx->libctx, "sha256", ctx->propq);
 128     if (ctx->sha256 == NULL) {
 129         OPENSSL_free(ctx);
 130         ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
 131         return 0;
 132     }
 133     return 1;
 134 }
 135
 136 static int set_property_query(KDF_SCRYPT *ctx, const char *propq)
 137 {
 138     OPENSSL_free(ctx->propq);
 139     ctx->propq = NULL;
 140     if (propq != NULL) {
 141         ctx->propq = OPENSSL_strdup(propq);
 142         if (ctx->propq == NULL) {
 143             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 144             return 0;
 145         }
 146     }
 147     return 1;
 148 }
 149
 150 static int kdf_scrypt_derive(void *vctx, unsigned char *key,
 151                              size_t keylen)
 152 {
 153     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
 154
 155     if (!ossl_prov_is_running())
 156         return 0;
 157
 158     if (ctx->pass == NULL) {
 159         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 160         return 0;
 161     }
 162
 163     if (ctx->salt == NULL) {
 164         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 165         return 0;
 166     }
 167
 168     if (ctx->sha256 == NULL && !set_digest(ctx))
 169         return 0;
 170
 171     return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
 172                       ctx->salt_len, ctx->N, ctx->r, ctx->p,
 173                       ctx->maxmem_bytes, key, keylen, ctx->sha256,
 174                       ctx->libctx, ctx->propq);
 175 }
 176
 177 static int is_power_of_two(uint64_t value)
 178 {
 179     return (value != 0) && ((value & (value - 1)) == 0);
 180 }
 181
 182 static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 183 {
 184     const OSSL_PARAM *p;
 185     KDF_SCRYPT *ctx = vctx;
 186     uint64_t u64_value;
 187
 188     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 189         if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
 190             return 0;
 191
 192     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 193         if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
 194             return 0;
 195
 196     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
 197         != NULL) {
 198         if (!OSSL_PARAM_get_uint64(p, &u64_value)
 199             || u64_value <= 1
 200             || !is_power_of_two(u64_value))
 201             return 0;
 202         ctx->N = u64_value;
 203     }
 204
 205     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
 206         != NULL) {
 207         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 208             return 0;
 209         ctx->r = u64_value;
 210     }
 211
 212     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
 213         != NULL) {
 214         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 215             return 0;
 216         ctx->p = u64_value;
 217     }
 218
 219     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
 220         != NULL) {
 221         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 222             return 0;
 223         ctx->maxmem_bytes = u64_value;
 224     }
 225
 226     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES);
 227     if (p != NULL) {
 228         if (p->data_type != OSSL_PARAM_UTF8_STRING
 229             || !set_property_query(ctx, p->data)
 230             || !set_digest(ctx))
 231             return 0;
 232     }
 233     return 1;
 234 }
 235
 236 static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(ossl_unused void *p_ctx)
 237 {
 238     static const OSSL_PARAM known_settable_ctx_params[] = {
 239         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 240         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 241         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
 242         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
 243         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
 244         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
 245         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 246         OSSL_PARAM_END
 247     };
 248     return known_settable_ctx_params;
 249 }
 250
 251 static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
 252 {
 253     OSSL_PARAM *p;
 254
 255     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 256         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 257     return -2;
 258 }
 259
 260 static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(ossl_unused void *p_ctx)
 261 {
 262     static const OSSL_PARAM known_gettable_ctx_params[] = {
 263         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 264         OSSL_PARAM_END
 265     };
 266     return known_gettable_ctx_params;
 267 }
 268
 269 const OSSL_DISPATCH ossl_kdf_scrypt_functions[] = {
 270     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
 271     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
 272     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
 273     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
 274     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 275       (void(*)(void))kdf_scrypt_settable_ctx_params },
 276     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
 277     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 278       (void(*)(void))kdf_scrypt_gettable_ctx_params },
 279     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
 280     { 0, NULL }
 281 };
 282
 283 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
 284 static void salsa208_word_specification(uint32_t inout[16])
 285 {
 286     int i;
 287     uint32_t x[16];
 288
 289     memcpy(x, inout, sizeof(x));
 290     for (i = 8; i > 0; i -= 2) {
 291         x[4] ^= R(x[0] + x[12], 7);
 292         x[8] ^= R(x[4] + x[0], 9);
 293         x[12] ^= R(x[8] + x[4], 13);
 294         x[0] ^= R(x[12] + x[8], 18);
 295         x[9] ^= R(x[5] + x[1], 7);
 296         x[13] ^= R(x[9] + x[5], 9);
 297         x[1] ^= R(x[13] + x[9], 13);
 298         x[5] ^= R(x[1] + x[13], 18);
 299         x[14] ^= R(x[10] + x[6], 7);
 300         x[2] ^= R(x[14] + x[10], 9);
 301         x[6] ^= R(x[2] + x[14], 13);
 302         x[10] ^= R(x[6] + x[2], 18);
 303         x[3] ^= R(x[15] + x[11], 7);
 304         x[7] ^= R(x[3] + x[15], 9);
 305         x[11] ^= R(x[7] + x[3], 13);
 306         x[15] ^= R(x[11] + x[7], 18);
 307         x[1] ^= R(x[0] + x[3], 7);
 308         x[2] ^= R(x[1] + x[0], 9);
 309         x[3] ^= R(x[2] + x[1], 13);
 310         x[0] ^= R(x[3] + x[2], 18);
 311         x[6] ^= R(x[5] + x[4], 7);
 312         x[7] ^= R(x[6] + x[5], 9);
 313         x[4] ^= R(x[7] + x[6], 13);
 314         x[5] ^= R(x[4] + x[7], 18);
 315         x[11] ^= R(x[10] + x[9], 7);
 316         x[8] ^= R(x[11] + x[10], 9);
 317         x[9] ^= R(x[8] + x[11], 13);
 318         x[10] ^= R(x[9] + x[8], 18);
 319         x[12] ^= R(x[15] + x[14], 7);
 320         x[13] ^= R(x[12] + x[15], 9);
 321         x[14] ^= R(x[13] + x[12], 13);
 322         x[15] ^= R(x[14] + x[13], 18);
 323     }
 324     for (i = 0; i < 16; ++i)
 325         inout[i] += x[i];
 326     OPENSSL_cleanse(x, sizeof(x));
 327 }
 328
 329 static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
 330 {
 331     uint64_t i, j;
 332     uint32_t X[16], *pB;
 333
 334     memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
 335     pB = B;
 336     for (i = 0; i < r * 2; i++) {
 337         for (j = 0; j < 16; j++)
 338             X[j] ^= *pB++;
 339         salsa208_word_specification(X);
 340         memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
 341     }
 342     OPENSSL_cleanse(X, sizeof(X));
 343 }
 344
 345 static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
 346                         uint32_t *X, uint32_t *T, uint32_t *V)
 347 {
 348     unsigned char *pB;
 349     uint32_t *pV;
 350     uint64_t i, k;
 351
 352     /* Convert from little endian input */
 353     for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
 354         *pV = *pB++;
 355         *pV |= *pB++ << 8;
 356         *pV |= *pB++ << 16;
 357         *pV |= (uint32_t)*pB++ << 24;
 358     }
 359
 360     for (i = 1; i < N; i++, pV += 32 * r)
 361         scryptBlockMix(pV, pV - 32 * r, r);
 362
 363     scryptBlockMix(X, V + (N - 1) * 32 * r, r);
 364
 365     for (i = 0; i < N; i++) {
 366         uint32_t j;
 367         j = X[16 * (2 * r - 1)] % N;
 368         pV = V + 32 * r * j;
 369         for (k = 0; k < 32 * r; k++)
 370             T[k] = X[k] ^ *pV++;
 371         scryptBlockMix(X, T, r);
 372     }
 373     /* Convert output to little endian */
 374     for (i = 0, pB = B; i < 32 * r; i++) {
 375         uint32_t xtmp = X[i];
 376         *pB++ = xtmp & 0xff;
 377         *pB++ = (xtmp >> 8) & 0xff;
 378         *pB++ = (xtmp >> 16) & 0xff;
 379         *pB++ = (xtmp >> 24) & 0xff;
 380     }
 381 }
 382
 383 #ifndef SIZE_MAX
 384 # define SIZE_MAX    ((size_t)-1)
 385 #endif
 386
 387 /*
 388  * Maximum power of two that will fit in uint64_t: this should work on
 389  * most (all?) platforms.
 390  */
 391
 392 #define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
 393
 394 /*
 395  * Maximum value of p * r:
 396  * p <= ((2^32-1) * hLen) / MFLen =>
 397  * p <= ((2^32-1) * 32) / (128 * r) =>
 398  * p * r <= (2^30-1)
 399  */
 400
 401 #define SCRYPT_PR_MAX   ((1 << 30) - 1)
 402
 403 static int scrypt_alg(const char *pass, size_t passlen,
 404                       const unsigned char *salt, size_t saltlen,
 405                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
 406                       unsigned char *key, size_t keylen, EVP_MD *sha256,
 407                       OSSL_LIB_CTX *libctx, const char *propq)
 408 {
 409     int rv = 0;
 410     unsigned char *B;
 411     uint32_t *X, *V, *T;
 412     uint64_t i, Blen, Vlen;
 413
 414     /* Sanity check parameters */
 415     /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
 416     if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
 417         return 0;
 418     /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
 419     if (p > SCRYPT_PR_MAX / r) {
 420         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 421         return 0;
 422     }
 423
 424     /*
 425      * Need to check N: if 2^(128 * r / 8) overflows limit this is
 426      * automatically satisfied since N <= UINT64_MAX.
 427      */
 428
 429     if (16 * r <= LOG2_UINT64_MAX) {
 430         if (N >= (((uint64_t)1) << (16 * r))) {
 431             ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 432             return 0;
 433         }
 434     }
 435
 436     /* Memory checks: check total allocated buffer size fits in uint64_t */
 437
 438     /*
 439      * B size in section 5 step 1.S
 440      * Note: we know p * 128 * r < UINT64_MAX because we already checked
 441      * p * r < SCRYPT_PR_MAX
 442      */
 443     Blen = p * 128 * r;
 444     /*
 445      * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
 446      * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
 447      */
 448     if (Blen > INT_MAX) {
 449         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 450         return 0;
 451     }
 452
 453     /*
 454      * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
 455      * This is combined size V, X and T (section 4)
 456      */
 457     i = UINT64_MAX / (32 * sizeof(uint32_t));
 458     if (N + 2 > i / r) {
 459         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 460         return 0;
 461     }
 462     Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
 463
 464     /* check total allocated size fits in uint64_t */
 465     if (Blen > UINT64_MAX - Vlen) {
 466         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 467         return 0;
 468     }
 469
 470     /* Check that the maximum memory doesn't exceed a size_t limits */
 471     if (maxmem > SIZE_MAX)
 472         maxmem = SIZE_MAX;
 473
 474     if (Blen + Vlen > maxmem) {
 475         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 476         return 0;
 477     }
 478
 479     /* If no key return to indicate parameters are OK */
 480     if (key == NULL)
 481         return 1;
 482
 483     B = OPENSSL_malloc((size_t)(Blen + Vlen));
 484     if (B == NULL) {
 485         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 486         return 0;
 487     }
 488     X = (uint32_t *)(B + Blen);
 489     T = X + 32 * r;
 490     V = T + 32 * r;
 491     if (pkcs5_pbkdf2_hmac_ex(pass, passlen, salt, saltlen, 1, sha256, (int)Blen,
 492                              B, libctx, propq) == 0)
 493         goto err;
 494
 495     for (i = 0; i < p; i++)
 496         scryptROMix(B + 128 * r * i, r, N, X, T, V);
 497
 498     if (pkcs5_pbkdf2_hmac_ex(pass, passlen, B, (int)Blen, 1, sha256, keylen,
 499                              key, libctx, propq) == 0)
 500         goto err;
 501     rv = 1;
 502  err:
 503     if (rv == 0)
 504         ERR_raise(ERR_LIB_EVP, EVP_R_PBKDF2_ERROR);
 505
 506     OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
 507     return rv;
 508 }
 509
 510 #endif