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     *buffer = NULL;
 112     *buflen = 0;
 113
 114     if (p->data_size == 0) {
 115         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 116             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 117             return 0;
 118         }
 119     } else if (p->data != NULL) {
 120         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 121             return 0;
 122     }
 123     return 1;
 124 }
 125
 126 static int set_digest(KDF_SCRYPT *ctx)
 127 {
 128     EVP_MD_free(ctx->sha256);
 129     ctx->sha256 = EVP_MD_fetch(ctx->libctx, "sha256", ctx->propq);
 130     if (ctx->sha256 == NULL) {
 131         OPENSSL_free(ctx);
 132         ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
 133         return 0;
 134     }
 135     return 1;
 136 }
 137
 138 static int set_property_query(KDF_SCRYPT *ctx, const char *propq)
 139 {
 140     OPENSSL_free(ctx->propq);
 141     ctx->propq = NULL;
 142     if (propq != NULL) {
 143         ctx->propq = OPENSSL_strdup(propq);
 144         if (ctx->propq == NULL) {
 145             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 146             return 0;
 147         }
 148     }
 149     return 1;
 150 }
 151
 152 static int kdf_scrypt_derive(void *vctx, unsigned char *key, size_t keylen,
 153                              const OSSL_PARAM params[])
 154 {
 155     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
 156
 157     if (!ossl_prov_is_running() || !kdf_scrypt_set_ctx_params(ctx, params))
 158         return 0;
 159
 160     if (ctx->pass == NULL) {
 161         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 162         return 0;
 163     }
 164
 165     if (ctx->salt == NULL) {
 166         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 167         return 0;
 168     }
 169
 170     if (ctx->sha256 == NULL && !set_digest(ctx))
 171         return 0;
 172
 173     return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
 174                       ctx->salt_len, ctx->N, ctx->r, ctx->p,
 175                       ctx->maxmem_bytes, key, keylen, ctx->sha256,
 176                       ctx->libctx, ctx->propq);
 177 }
 178
 179 static int is_power_of_two(uint64_t value)
 180 {
 181     return (value != 0) && ((value & (value - 1)) == 0);
 182 }
 183
 184 static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 185 {
 186     const OSSL_PARAM *p;
 187     KDF_SCRYPT *ctx = vctx;
 188     uint64_t u64_value;
 189
 190     if (params == NULL)
 191         return 1;
 192
 193     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 194         if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
 195             return 0;
 196
 197     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 198         if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
 199             return 0;
 200
 201     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
 202         != NULL) {
 203         if (!OSSL_PARAM_get_uint64(p, &u64_value)
 204             || u64_value <= 1
 205             || !is_power_of_two(u64_value))
 206             return 0;
 207         ctx->N = u64_value;
 208     }
 209
 210     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
 211         != NULL) {
 212         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 213             return 0;
 214         ctx->r = u64_value;
 215     }
 216
 217     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
 218         != NULL) {
 219         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 220             return 0;
 221         ctx->p = u64_value;
 222     }
 223
 224     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
 225         != NULL) {
 226         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 227             return 0;
 228         ctx->maxmem_bytes = u64_value;
 229     }
 230
 231     p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES);
 232     if (p != NULL) {
 233         if (p->data_type != OSSL_PARAM_UTF8_STRING
 234             || !set_property_query(ctx, p->data)
 235             || !set_digest(ctx))
 236             return 0;
 237     }
 238     return 1;
 239 }
 240
 241 static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(ossl_unused void *ctx,
 242                                                         ossl_unused void *p_ctx)
 243 {
 244     static const OSSL_PARAM known_settable_ctx_params[] = {
 245         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 246         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 247         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
 248         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
 249         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
 250         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
 251         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 252         OSSL_PARAM_END
 253     };
 254     return known_settable_ctx_params;
 255 }
 256
 257 static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
 258 {
 259     OSSL_PARAM *p;
 260
 261     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 262         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 263     return -2;
 264 }
 265
 266 static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(ossl_unused void *ctx,
 267                                                         ossl_unused void *p_ctx)
 268 {
 269     static const OSSL_PARAM known_gettable_ctx_params[] = {
 270         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 271         OSSL_PARAM_END
 272     };
 273     return known_gettable_ctx_params;
 274 }
 275
 276 const OSSL_DISPATCH ossl_kdf_scrypt_functions[] = {
 277     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
 278     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
 279     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
 280     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
 281     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 282       (void(*)(void))kdf_scrypt_settable_ctx_params },
 283     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
 284     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 285       (void(*)(void))kdf_scrypt_gettable_ctx_params },
 286     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
 287     { 0, NULL }
 288 };
 289
 290 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
 291 static void salsa208_word_specification(uint32_t inout[16])
 292 {
 293     int i;
 294     uint32_t x[16];
 295
 296     memcpy(x, inout, sizeof(x));
 297     for (i = 8; i > 0; i -= 2) {
 298         x[4] ^= R(x[0] + x[12], 7);
 299         x[8] ^= R(x[4] + x[0], 9);
 300         x[12] ^= R(x[8] + x[4], 13);
 301         x[0] ^= R(x[12] + x[8], 18);
 302         x[9] ^= R(x[5] + x[1], 7);
 303         x[13] ^= R(x[9] + x[5], 9);
 304         x[1] ^= R(x[13] + x[9], 13);
 305         x[5] ^= R(x[1] + x[13], 18);
 306         x[14] ^= R(x[10] + x[6], 7);
 307         x[2] ^= R(x[14] + x[10], 9);
 308         x[6] ^= R(x[2] + x[14], 13);
 309         x[10] ^= R(x[6] + x[2], 18);
 310         x[3] ^= R(x[15] + x[11], 7);
 311         x[7] ^= R(x[3] + x[15], 9);
 312         x[11] ^= R(x[7] + x[3], 13);
 313         x[15] ^= R(x[11] + x[7], 18);
 314         x[1] ^= R(x[0] + x[3], 7);
 315         x[2] ^= R(x[1] + x[0], 9);
 316         x[3] ^= R(x[2] + x[1], 13);
 317         x[0] ^= R(x[3] + x[2], 18);
 318         x[6] ^= R(x[5] + x[4], 7);
 319         x[7] ^= R(x[6] + x[5], 9);
 320         x[4] ^= R(x[7] + x[6], 13);
 321         x[5] ^= R(x[4] + x[7], 18);
 322         x[11] ^= R(x[10] + x[9], 7);
 323         x[8] ^= R(x[11] + x[10], 9);
 324         x[9] ^= R(x[8] + x[11], 13);
 325         x[10] ^= R(x[9] + x[8], 18);
 326         x[12] ^= R(x[15] + x[14], 7);
 327         x[13] ^= R(x[12] + x[15], 9);
 328         x[14] ^= R(x[13] + x[12], 13);
 329         x[15] ^= R(x[14] + x[13], 18);
 330     }
 331     for (i = 0; i < 16; ++i)
 332         inout[i] += x[i];
 333     OPENSSL_cleanse(x, sizeof(x));
 334 }
 335
 336 static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
 337 {
 338     uint64_t i, j;
 339     uint32_t X[16], *pB;
 340
 341     memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
 342     pB = B;
 343     for (i = 0; i < r * 2; i++) {
 344         for (j = 0; j < 16; j++)
 345             X[j] ^= *pB++;
 346         salsa208_word_specification(X);
 347         memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
 348     }
 349     OPENSSL_cleanse(X, sizeof(X));
 350 }
 351
 352 static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
 353                         uint32_t *X, uint32_t *T, uint32_t *V)
 354 {
 355     unsigned char *pB;
 356     uint32_t *pV;
 357     uint64_t i, k;
 358
 359     /* Convert from little endian input */
 360     for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
 361         *pV = *pB++;
 362         *pV |= *pB++ << 8;
 363         *pV |= *pB++ << 16;
 364         *pV |= (uint32_t)*pB++ << 24;
 365     }
 366
 367     for (i = 1; i < N; i++, pV += 32 * r)
 368         scryptBlockMix(pV, pV - 32 * r, r);
 369
 370     scryptBlockMix(X, V + (N - 1) * 32 * r, r);
 371
 372     for (i = 0; i < N; i++) {
 373         uint32_t j;
 374         j = X[16 * (2 * r - 1)] % N;
 375         pV = V + 32 * r * j;
 376         for (k = 0; k < 32 * r; k++)
 377             T[k] = X[k] ^ *pV++;
 378         scryptBlockMix(X, T, r);
 379     }
 380     /* Convert output to little endian */
 381     for (i = 0, pB = B; i < 32 * r; i++) {
 382         uint32_t xtmp = X[i];
 383         *pB++ = xtmp & 0xff;
 384         *pB++ = (xtmp >> 8) & 0xff;
 385         *pB++ = (xtmp >> 16) & 0xff;
 386         *pB++ = (xtmp >> 24) & 0xff;
 387     }
 388 }
 389
 390 #ifndef SIZE_MAX
 391 # define SIZE_MAX    ((size_t)-1)
 392 #endif
 393
 394 /*
 395  * Maximum power of two that will fit in uint64_t: this should work on
 396  * most (all?) platforms.
 397  */
 398
 399 #define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
 400
 401 /*
 402  * Maximum value of p * r:
 403  * p <= ((2^32-1) * hLen) / MFLen =>
 404  * p <= ((2^32-1) * 32) / (128 * r) =>
 405  * p * r <= (2^30-1)
 406  */
 407
 408 #define SCRYPT_PR_MAX   ((1 << 30) - 1)
 409
 410 static int scrypt_alg(const char *pass, size_t passlen,
 411                       const unsigned char *salt, size_t saltlen,
 412                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
 413                       unsigned char *key, size_t keylen, EVP_MD *sha256,
 414                       OSSL_LIB_CTX *libctx, const char *propq)
 415 {
 416     int rv = 0;
 417     unsigned char *B;
 418     uint32_t *X, *V, *T;
 419     uint64_t i, Blen, Vlen;
 420
 421     /* Sanity check parameters */
 422     /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
 423     if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
 424         return 0;
 425     /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
 426     if (p > SCRYPT_PR_MAX / r) {
 427         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 428         return 0;
 429     }
 430
 431     /*
 432      * Need to check N: if 2^(128 * r / 8) overflows limit this is
 433      * automatically satisfied since N <= UINT64_MAX.
 434      */
 435
 436     if (16 * r <= LOG2_UINT64_MAX) {
 437         if (N >= (((uint64_t)1) << (16 * r))) {
 438             ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 439             return 0;
 440         }
 441     }
 442
 443     /* Memory checks: check total allocated buffer size fits in uint64_t */
 444
 445     /*
 446      * B size in section 5 step 1.S
 447      * Note: we know p * 128 * r < UINT64_MAX because we already checked
 448      * p * r < SCRYPT_PR_MAX
 449      */
 450     Blen = p * 128 * r;
 451     /*
 452      * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
 453      * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
 454      */
 455     if (Blen > INT_MAX) {
 456         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 457         return 0;
 458     }
 459
 460     /*
 461      * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
 462      * This is combined size V, X and T (section 4)
 463      */
 464     i = UINT64_MAX / (32 * sizeof(uint32_t));
 465     if (N + 2 > i / r) {
 466         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 467         return 0;
 468     }
 469     Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
 470
 471     /* check total allocated size fits in uint64_t */
 472     if (Blen > UINT64_MAX - Vlen) {
 473         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 474         return 0;
 475     }
 476
 477     /* Check that the maximum memory doesn't exceed a size_t limits */
 478     if (maxmem > SIZE_MAX)
 479         maxmem = SIZE_MAX;
 480
 481     if (Blen + Vlen > maxmem) {
 482         ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
 483         return 0;
 484     }
 485
 486     /* If no key return to indicate parameters are OK */
 487     if (key == NULL)
 488         return 1;
 489
 490     B = OPENSSL_malloc((size_t)(Blen + Vlen));
 491     if (B == NULL) {
 492         ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
 493         return 0;
 494     }
 495     X = (uint32_t *)(B + Blen);
 496     T = X + 32 * r;
 497     V = T + 32 * r;
 498     if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, salt, saltlen, 1, sha256,
 499                                   (int)Blen, B, libctx, propq) == 0)
 500         goto err;
 501
 502     for (i = 0; i < p; i++)
 503         scryptROMix(B + 128 * r * i, r, N, X, T, V);
 504
 505     if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, B, (int)Blen, 1, sha256,
 506                                   keylen, key, libctx, propq) == 0)
 507         goto err;
 508     rv = 1;
 509  err:
 510     if (rv == 0)
 511         ERR_raise(ERR_LIB_EVP, EVP_R_PBKDF2_ERROR);
 512
 513     OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
 514     return rv;
 515 }
 516
 517 #endif