providers/implementations/kdfs/pbkdf2.c

   1 /*
   2  * Copyright 2018-2022 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 /*
  11  * HMAC low level APIs are deprecated for public use, but still ok for internal
  12  * use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <stdlib.h>
  17 #include <stdarg.h>
  18 #include <string.h>
  19 #include <openssl/hmac.h>
  20 #include <openssl/evp.h>
  21 #include <openssl/kdf.h>
  22 #include <openssl/core_names.h>
  23 #include <openssl/proverr.h>
  24 #include "internal/cryptlib.h"
  25 #include "internal/numbers.h"
  26 #include "crypto/evp.h"
  27 #include "prov/provider_ctx.h"
  28 #include "prov/providercommon.h"
  29 #include "prov/implementations.h"
  30 #include "prov/provider_util.h"
  31 #include "pbkdf2.h"
  32
  33 /* Constants specified in SP800-132 */
  34 #define KDF_PBKDF2_MIN_KEY_LEN_BITS  112
  35 #define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF
  36 #define KDF_PBKDF2_MIN_ITERATIONS 1000
  37 #define KDF_PBKDF2_MIN_SALT_LEN   (128 / 8)
  38
  39 static OSSL_FUNC_kdf_newctx_fn kdf_pbkdf2_new;
  40 static OSSL_FUNC_kdf_dupctx_fn kdf_pbkdf2_dup;
  41 static OSSL_FUNC_kdf_freectx_fn kdf_pbkdf2_free;
  42 static OSSL_FUNC_kdf_reset_fn kdf_pbkdf2_reset;
  43 static OSSL_FUNC_kdf_derive_fn kdf_pbkdf2_derive;
  44 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_pbkdf2_settable_ctx_params;
  45 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_pbkdf2_set_ctx_params;
  46 static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_pbkdf2_gettable_ctx_params;
  47 static OSSL_FUNC_kdf_get_ctx_params_fn kdf_pbkdf2_get_ctx_params;
  48
  49 static int pbkdf2_derive(const char *pass, size_t passlen,
  50                          const unsigned char *salt, int saltlen, uint64_t iter,
  51                          const EVP_MD *digest, unsigned char *key,
  52                          size_t keylen, int extra_checks);
  53
  54 typedef struct {
  55     void *provctx;
  56     unsigned char *pass;
  57     size_t pass_len;
  58     unsigned char *salt;
  59     size_t salt_len;
  60     uint64_t iter;
  61     PROV_DIGEST digest;
  62     int lower_bound_checks;
  63 } KDF_PBKDF2;
  64
  65 static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx);
  66
  67 static void *kdf_pbkdf2_new_no_init(void *provctx)
  68 {
  69     KDF_PBKDF2 *ctx;
  70
  71     if (!ossl_prov_is_running())
  72         return NULL;
  73
  74     ctx = OPENSSL_zalloc(sizeof(*ctx));
  75     if (ctx == NULL)
  76         return NULL;
  77     ctx->provctx = provctx;
  78     return ctx;
  79 }
  80
  81 static void *kdf_pbkdf2_new(void *provctx)
  82 {
  83     KDF_PBKDF2 *ctx = kdf_pbkdf2_new_no_init(provctx);
  84
  85     if (ctx != NULL)
  86         kdf_pbkdf2_init(ctx);
  87     return ctx;
  88 }
  89
  90 static void kdf_pbkdf2_cleanup(KDF_PBKDF2 *ctx)
  91 {
  92     ossl_prov_digest_reset(&ctx->digest);
  93     OPENSSL_free(ctx->salt);
  94     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  95     memset(ctx, 0, sizeof(*ctx));
  96 }
  97
  98 static void kdf_pbkdf2_free(void *vctx)
  99 {
 100     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
 101
 102     if (ctx != NULL) {
 103         kdf_pbkdf2_cleanup(ctx);
 104         OPENSSL_free(ctx);
 105     }
 106 }
 107
 108 static void kdf_pbkdf2_reset(void *vctx)
 109 {
 110     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
 111     void *provctx = ctx->provctx;
 112
 113     kdf_pbkdf2_cleanup(ctx);
 114     ctx->provctx = provctx;
 115     kdf_pbkdf2_init(ctx);
 116 }
 117
 118 static void *kdf_pbkdf2_dup(void *vctx)
 119 {
 120     const KDF_PBKDF2 *src = (const KDF_PBKDF2 *)vctx;
 121     KDF_PBKDF2 *dest;
 122
 123     /* We need a new PBKDF2 object but uninitialised since we're filling it */
 124     dest = kdf_pbkdf2_new_no_init(src->provctx);
 125     if (dest != NULL) {
 126         if (!ossl_prov_memdup(src->salt, src->salt_len,
 127                               &dest->salt, &dest->salt_len)
 128                 || !ossl_prov_memdup(src->pass, src->pass_len,
 129                                      &dest->pass, &dest->pass_len)
 130                 || !ossl_prov_digest_copy(&dest->digest, &src->digest))
 131             goto err;
 132         dest->iter = src->iter;
 133         dest->lower_bound_checks = src->lower_bound_checks;
 134     }
 135     return dest;
 136
 137  err:
 138     kdf_pbkdf2_free(dest);
 139     return NULL;
 140 }
 141
 142 static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx)
 143 {
 144     OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
 145     OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
 146
 147     params[0] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
 148                                                  SN_sha1, 0);
 149     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 150         /* This is an error, but there is no way to indicate such directly */
 151         ossl_prov_digest_reset(&ctx->digest);
 152     ctx->iter = PKCS5_DEFAULT_ITER;
 153     ctx->lower_bound_checks = ossl_kdf_pbkdf2_default_checks;
 154 }
 155
 156 static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
 157                              const OSSL_PARAM *p)
 158 {
 159     OPENSSL_clear_free(*buffer, *buflen);
 160     *buffer = NULL;
 161     *buflen = 0;
 162
 163     if (p->data_size == 0) {
 164         if ((*buffer = OPENSSL_malloc(1)) == NULL)
 165             return 0;
 166     } else if (p->data != NULL) {
 167         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 168             return 0;
 169     }
 170     return 1;
 171 }
 172
 173 static int kdf_pbkdf2_derive(void *vctx, unsigned char *key, size_t keylen,
 174                              const OSSL_PARAM params[])
 175 {
 176     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
 177     const EVP_MD *md;
 178
 179     if (!ossl_prov_is_running() || !kdf_pbkdf2_set_ctx_params(ctx, params))
 180         return 0;
 181
 182     if (ctx->pass == NULL) {
 183         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 184         return 0;
 185     }
 186
 187     if (ctx->salt == NULL) {
 188         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 189         return 0;
 190     }
 191
 192     md = ossl_prov_digest_md(&ctx->digest);
 193     return pbkdf2_derive((char *)ctx->pass, ctx->pass_len,
 194                          ctx->salt, ctx->salt_len, ctx->iter,
 195                          md, key, keylen, ctx->lower_bound_checks);
 196 }
 197
 198 static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 199 {
 200     const OSSL_PARAM *p;
 201     KDF_PBKDF2 *ctx = vctx;
 202     OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
 203     int pkcs5;
 204     uint64_t iter, min_iter;
 205
 206     if (params == NULL)
 207         return 1;
 208
 209     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 210         return 0;
 211
 212     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PKCS5)) != NULL) {
 213         if (!OSSL_PARAM_get_int(p, &pkcs5))
 214             return 0;
 215         ctx->lower_bound_checks = pkcs5 == 0;
 216     }
 217
 218     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 219         if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p))
 220             return 0;
 221
 222     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) {
 223         if (ctx->lower_bound_checks != 0
 224             && p->data_size < KDF_PBKDF2_MIN_SALT_LEN) {
 225             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
 226             return 0;
 227         }
 228         if (!pbkdf2_set_membuf(&ctx->salt, &ctx->salt_len, p))
 229             return 0;
 230     }
 231
 232     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_ITER)) != NULL) {
 233         if (!OSSL_PARAM_get_uint64(p, &iter))
 234             return 0;
 235         min_iter = ctx->lower_bound_checks != 0 ? KDF_PBKDF2_MIN_ITERATIONS : 1;
 236         if (iter < min_iter) {
 237             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
 238             return 0;
 239         }
 240         ctx->iter = iter;
 241     }
 242     return 1;
 243 }
 244
 245 static const OSSL_PARAM *kdf_pbkdf2_settable_ctx_params(ossl_unused void *ctx,
 246                                                         ossl_unused void *p_ctx)
 247 {
 248     static const OSSL_PARAM known_settable_ctx_params[] = {
 249         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 250         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 251         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 252         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 253         OSSL_PARAM_uint64(OSSL_KDF_PARAM_ITER, NULL),
 254         OSSL_PARAM_int(OSSL_KDF_PARAM_PKCS5, NULL),
 255         OSSL_PARAM_END
 256     };
 257     return known_settable_ctx_params;
 258 }
 259
 260 static int kdf_pbkdf2_get_ctx_params(void *vctx, OSSL_PARAM params[])
 261 {
 262     OSSL_PARAM *p;
 263
 264     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 265         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 266     return -2;
 267 }
 268
 269 static const OSSL_PARAM *kdf_pbkdf2_gettable_ctx_params(ossl_unused void *ctx,
 270                                                         ossl_unused void *p_ctx)
 271 {
 272     static const OSSL_PARAM known_gettable_ctx_params[] = {
 273         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 274         OSSL_PARAM_END
 275     };
 276     return known_gettable_ctx_params;
 277 }
 278
 279 const OSSL_DISPATCH ossl_kdf_pbkdf2_functions[] = {
 280     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_pbkdf2_new },
 281     { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_pbkdf2_dup },
 282     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_pbkdf2_free },
 283     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_pbkdf2_reset },
 284     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_pbkdf2_derive },
 285     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 286       (void(*)(void))kdf_pbkdf2_settable_ctx_params },
 287     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_set_ctx_params },
 288     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 289       (void(*)(void))kdf_pbkdf2_gettable_ctx_params },
 290     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_get_ctx_params },
 291     { 0, NULL }
 292 };
 293
 294 /*
 295  * This is an implementation of PKCS#5 v2.0 password based encryption key
 296  * derivation function PBKDF2. SHA1 version verified against test vectors
 297  * posted by Peter Gutmann to the PKCS-TNG mailing list.
 298  *
 299  * The constraints specified by SP800-132 have been added i.e.
 300  *  - Check the range of the key length.
 301  *  - Minimum iteration count of 1000.
 302  *  - Randomly-generated portion of the salt shall be at least 128 bits.
 303  */
 304 static int pbkdf2_derive(const char *pass, size_t passlen,
 305                          const unsigned char *salt, int saltlen, uint64_t iter,
 306                          const EVP_MD *digest, unsigned char *key,
 307                          size_t keylen, int lower_bound_checks)
 308 {
 309     int ret = 0;
 310     unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];
 311     int cplen, k, tkeylen, mdlen;
 312     uint64_t j;
 313     unsigned long i = 1;
 314     HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;
 315
 316     mdlen = EVP_MD_get_size(digest);
 317     if (mdlen <= 0)
 318         return 0;
 319
 320     /*
 321      * This check should always be done because keylen / mdlen >= (2^32 - 1)
 322      * results in an overflow of the loop counter 'i'.
 323      */
 324     if ((keylen / mdlen) >= KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO) {
 325         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 326         return 0;
 327     }
 328
 329     if (lower_bound_checks) {
 330         if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
 331             ERR_raise(ERR_LIB_PROV, PROV_R_KEY_SIZE_TOO_SMALL);
 332             return 0;
 333         }
 334         if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {
 335             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
 336             return 0;
 337         }
 338         if (iter < KDF_PBKDF2_MIN_ITERATIONS) {
 339             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
 340             return 0;
 341         }
 342     }
 343
 344     hctx_tpl = HMAC_CTX_new();
 345     if (hctx_tpl == NULL)
 346         return 0;
 347     p = key;
 348     tkeylen = keylen;
 349     if (!HMAC_Init_ex(hctx_tpl, pass, passlen, digest, NULL))
 350         goto err;
 351     hctx = HMAC_CTX_new();
 352     if (hctx == NULL)
 353         goto err;
 354     while (tkeylen) {
 355         if (tkeylen > mdlen)
 356             cplen = mdlen;
 357         else
 358             cplen = tkeylen;
 359         /*
 360          * We are unlikely to ever use more than 256 blocks (5120 bits!) but
 361          * just in case...
 362          */
 363         itmp[0] = (unsigned char)((i >> 24) & 0xff);
 364         itmp[1] = (unsigned char)((i >> 16) & 0xff);
 365         itmp[2] = (unsigned char)((i >> 8) & 0xff);
 366         itmp[3] = (unsigned char)(i & 0xff);
 367         if (!HMAC_CTX_copy(hctx, hctx_tpl))
 368             goto err;
 369         if (!HMAC_Update(hctx, salt, saltlen)
 370                 || !HMAC_Update(hctx, itmp, 4)
 371                 || !HMAC_Final(hctx, digtmp, NULL))
 372             goto err;
 373         memcpy(p, digtmp, cplen);
 374         for (j = 1; j < iter; j++) {
 375             if (!HMAC_CTX_copy(hctx, hctx_tpl))
 376                 goto err;
 377             if (!HMAC_Update(hctx, digtmp, mdlen)
 378                     || !HMAC_Final(hctx, digtmp, NULL))
 379                 goto err;
 380             for (k = 0; k < cplen; k++)
 381                 p[k] ^= digtmp[k];
 382         }
 383         tkeylen -= cplen;
 384         i++;
 385         p += cplen;
 386     }
 387     ret = 1;
 388
 389 err:
 390     HMAC_CTX_free(hctx);
 391     HMAC_CTX_free(hctx_tpl);
 392     return ret;
 393 }