providers/common/kdfs/pbkdf2.c

   1 /*
   2  * Copyright 2018-2019 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/hmac.h>
  14 #include <openssl/evp.h>
  15 #include <openssl/kdf.h>
  16 #include <openssl/core_names.h>
  17 #include "internal/cryptlib.h"
  18 #include "internal/numbers.h"
  19 #include "internal/evp_int.h"
  20 #include "internal/provider_ctx.h"
  21 #include "internal/providercommonerr.h"
  22 #include "internal/provider_algs.h"
  23
  24 /* Constants specified in SP800-132 */
  25 #define KDF_PBKDF2_MIN_KEY_LEN_BITS  112
  26 #define KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO 0xFFFFFFFF
  27 #define KDF_PBKDF2_MIN_ITERATIONS 1000
  28 #define KDF_PBKDF2_MIN_SALT_LEN   (128 / 8)
  29 /*
  30  * For backwards compatibility reasons,
  31  * Extra checks are done by default in fips mode only.
  32  */
  33 #ifdef FIPS_MODE
  34 # define KDF_PBKDF2_DEFAULT_CHECKS 1
  35 #else
  36 # define KDF_PBKDF2_DEFAULT_CHECKS 0
  37 #endif /* FIPS_MODE */
  38
  39 static OSSL_OP_kdf_newctx_fn kdf_pbkdf2_new;
  40 static OSSL_OP_kdf_freectx_fn kdf_pbkdf2_free;
  41 static OSSL_OP_kdf_reset_fn kdf_pbkdf2_reset;
  42 static OSSL_OP_kdf_derive_fn kdf_pbkdf2_derive;
  43 static OSSL_OP_kdf_settable_ctx_params_fn kdf_pbkdf2_settable_ctx_params;
  44 static OSSL_OP_kdf_set_ctx_params_fn kdf_pbkdf2_set_ctx_params;
  45
  46 static int  pbkdf2_derive(const char *pass, size_t passlen,
  47                           const unsigned char *salt, int saltlen, uint64_t iter,
  48                           const EVP_MD *digest, unsigned char *key,
  49                           size_t keylen, int extra_checks);
  50
  51 typedef struct {
  52     void *provctx;
  53     unsigned char *pass;
  54     size_t pass_len;
  55     unsigned char *salt;
  56     size_t salt_len;
  57     uint64_t iter;
  58     EVP_MD *md;
  59     int lower_bound_checks;
  60 } KDF_PBKDF2;
  61
  62 static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx);
  63
  64 static void *kdf_pbkdf2_new(void *provctx)
  65 {
  66     KDF_PBKDF2 *ctx;
  67
  68     ctx = OPENSSL_zalloc(sizeof(*ctx));
  69     if (ctx == NULL) {
  70         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
  71         return NULL;
  72     }
  73     ctx->provctx = provctx;
  74     kdf_pbkdf2_init(ctx);
  75     return ctx;
  76 }
  77
  78 static void kdf_pbkdf2_free(void *vctx)
  79 {
  80     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
  81
  82     kdf_pbkdf2_reset(ctx);
  83     EVP_MD_meth_free(ctx->md);
  84     OPENSSL_free(ctx);
  85 }
  86
  87 static void kdf_pbkdf2_reset(void *vctx)
  88 {
  89     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
  90
  91     OPENSSL_free(ctx->salt);
  92     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  93     memset(ctx, 0, sizeof(*ctx));
  94     kdf_pbkdf2_init(ctx);
  95 }
  96
  97 static void kdf_pbkdf2_init(KDF_PBKDF2 *ctx)
  98 {
  99     ctx->iter = PKCS5_DEFAULT_ITER;
 100     ctx->md = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(ctx->provctx), SN_sha1,
 101                            NULL);
 102     ctx->lower_bound_checks = KDF_PBKDF2_DEFAULT_CHECKS;
 103 }
 104
 105 static int pbkdf2_set_membuf(unsigned char **buffer, size_t *buflen,
 106                              const OSSL_PARAM *p)
 107 {
 108     OPENSSL_clear_free(*buffer, *buflen);
 109     if (p->data_size == 0) {
 110         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 111             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 112             return 0;
 113         }
 114     } else if (p->data != NULL) {
 115         *buffer = NULL;
 116         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 117             return 0;
 118     }
 119     return 1;
 120 }
 121
 122 static int kdf_pbkdf2_derive(void *vctx, unsigned char *key,
 123                              size_t keylen)
 124 {
 125     KDF_PBKDF2 *ctx = (KDF_PBKDF2 *)vctx;
 126
 127     if (ctx->pass == NULL) {
 128         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 129         return 0;
 130     }
 131
 132     if (ctx->salt == NULL) {
 133         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 134         return 0;
 135     }
 136
 137     return pbkdf2_derive((char *)ctx->pass, ctx->pass_len,
 138                          ctx->salt, ctx->salt_len, ctx->iter,
 139                          ctx->md, key, keylen, ctx->lower_bound_checks);
 140 }
 141
 142 static int kdf_pbkdf2_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 143 {
 144     const OSSL_PARAM *p;
 145     KDF_PBKDF2 *ctx = vctx;
 146     EVP_MD *md;
 147     int pkcs5;
 148     uint64_t iter, min_iter;
 149     const char *properties = NULL;
 150
 151     /* Grab search properties, this should be before the digest lookup */
 152     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES))
 153         != NULL) {
 154         if (p->data_type != OSSL_PARAM_UTF8_STRING)
 155             return 0;
 156         properties = p->data;
 157     }
 158     /* Handle aliasing of digest parameter names */
 159     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DIGEST)) != NULL) {
 160         if (p->data_type != OSSL_PARAM_UTF8_STRING)
 161             return 0;
 162         md = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(ctx->provctx), p->data,
 163                           properties);
 164         if (md == NULL) {
 165             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST);
 166             return 0;
 167         }
 168         EVP_MD_meth_free(ctx->md);
 169         ctx->md = md;
 170     }
 171
 172     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PKCS5)) != NULL) {
 173         if (!OSSL_PARAM_get_int(p, &pkcs5))
 174             return 0;
 175         ctx->lower_bound_checks = pkcs5 == 0;
 176     }
 177
 178     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 179         if (!pbkdf2_set_membuf(&ctx->pass, &ctx->pass_len, p))
 180             return 0;
 181
 182     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL) {
 183         if (ctx->lower_bound_checks != 0
 184             && p->data_size < KDF_PBKDF2_MIN_SALT_LEN) {
 185             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
 186             return 0;
 187         }
 188         if (!pbkdf2_set_membuf(&ctx->salt, &ctx->salt_len,p))
 189             return 0;
 190     }
 191
 192     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_ITER)) != NULL) {
 193         if (!OSSL_PARAM_get_uint64(p, &iter))
 194             return 0;
 195         min_iter = ctx->lower_bound_checks != 0 ? KDF_PBKDF2_MIN_ITERATIONS : 1;
 196         if (iter < min_iter) {
 197             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
 198             return 0;
 199         }
 200         ctx->iter = iter;
 201     }
 202     return 1;
 203 }
 204
 205 static const OSSL_PARAM *kdf_pbkdf2_settable_ctx_params(void)
 206 {
 207     static const OSSL_PARAM known_settable_ctx_params[] = {
 208         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 209         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 210         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 211         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 212         OSSL_PARAM_uint64(OSSL_KDF_PARAM_ITER, NULL),
 213         OSSL_PARAM_int(OSSL_KDF_PARAM_PKCS5, NULL),
 214         OSSL_PARAM_END
 215     };
 216     return known_settable_ctx_params;
 217 }
 218
 219 static int kdf_pbkdf2_get_ctx_params(void *vctx, OSSL_PARAM params[])
 220 {
 221     OSSL_PARAM *p;
 222
 223     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 224         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 225     return -2;
 226 }
 227
 228 static const OSSL_PARAM *kdf_pbkdf2_gettable_ctx_params(void)
 229 {
 230     static const OSSL_PARAM known_gettable_ctx_params[] = {
 231         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 232         OSSL_PARAM_END
 233     };
 234     return known_gettable_ctx_params;
 235 }
 236
 237 const OSSL_DISPATCH kdf_pbkdf2_functions[] = {
 238     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_pbkdf2_new },
 239     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_pbkdf2_free },
 240     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_pbkdf2_reset },
 241     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_pbkdf2_derive },
 242     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 243       (void(*)(void))kdf_pbkdf2_settable_ctx_params },
 244     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_set_ctx_params },
 245     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 246       (void(*)(void))kdf_pbkdf2_gettable_ctx_params },
 247     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_pbkdf2_get_ctx_params },
 248     { 0, NULL }
 249 };
 250
 251 /*
 252  * This is an implementation of PKCS#5 v2.0 password based encryption key
 253  * derivation function PBKDF2. SHA1 version verified against test vectors
 254  * posted by Peter Gutmann to the PKCS-TNG mailing list.
 255  *
 256  * The constraints specified by SP800-132 have been added i.e.
 257  *  - Check the range of the key length.
 258  *  - Minimum iteration count of 1000.
 259  *  - Randomly-generated portion of the salt shall be at least 128 bits.
 260  */
 261 static int pbkdf2_derive(const char *pass, size_t passlen,
 262                          const unsigned char *salt, int saltlen, uint64_t iter,
 263                          const EVP_MD *digest, unsigned char *key,
 264                          size_t keylen, int lower_bound_checks)
 265 {
 266     int ret = 0;
 267     unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];
 268     int cplen, k, tkeylen, mdlen;
 269     uint64_t j;
 270     unsigned long i = 1;
 271     HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;
 272
 273     mdlen = EVP_MD_size(digest);
 274     if (mdlen <= 0)
 275         return 0;
 276
 277     /*
 278      * This check should always be done because keylen / mdlen >= (2^32 - 1)
 279      * results in an overflow of the loop counter 'i'.
 280      */
 281     if ((keylen / mdlen) >= KDF_PBKDF2_MAX_KEY_LEN_DIGEST_RATIO) {
 282         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LEN);
 283         return 0;
 284     }
 285
 286     if (lower_bound_checks) {
 287         if ((keylen * 8) < KDF_PBKDF2_MIN_KEY_LEN_BITS) {
 288             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LEN);
 289             return 0;
 290         }
 291         if (saltlen < KDF_PBKDF2_MIN_SALT_LEN) {
 292             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SALT_LENGTH);
 293             return 0;
 294         }
 295         if (iter < KDF_PBKDF2_MIN_ITERATIONS) {
 296             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_ITERATION_COUNT);
 297             return 0;
 298         }
 299     }
 300
 301     hctx_tpl = HMAC_CTX_new();
 302     if (hctx_tpl == NULL)
 303         return 0;
 304     p = key;
 305     tkeylen = keylen;
 306     if (!HMAC_Init_ex(hctx_tpl, pass, passlen, digest, NULL))
 307         goto err;
 308     hctx = HMAC_CTX_new();
 309     if (hctx == NULL)
 310         goto err;
 311     while (tkeylen) {
 312         if (tkeylen > mdlen)
 313             cplen = mdlen;
 314         else
 315             cplen = tkeylen;
 316         /*
 317          * We are unlikely to ever use more than 256 blocks (5120 bits!) but
 318          * just in case...
 319          */
 320         itmp[0] = (unsigned char)((i >> 24) & 0xff);
 321         itmp[1] = (unsigned char)((i >> 16) & 0xff);
 322         itmp[2] = (unsigned char)((i >> 8) & 0xff);
 323         itmp[3] = (unsigned char)(i & 0xff);
 324         if (!HMAC_CTX_copy(hctx, hctx_tpl))
 325             goto err;
 326         if (!HMAC_Update(hctx, salt, saltlen)
 327                 || !HMAC_Update(hctx, itmp, 4)
 328                 || !HMAC_Final(hctx, digtmp, NULL))
 329             goto err;
 330         memcpy(p, digtmp, cplen);
 331         for (j = 1; j < iter; j++) {
 332             if (!HMAC_CTX_copy(hctx, hctx_tpl))
 333                 goto err;
 334             if (!HMAC_Update(hctx, digtmp, mdlen)
 335                     || !HMAC_Final(hctx, digtmp, NULL))
 336                 goto err;
 337             for (k = 0; k < cplen; k++)
 338                 p[k] ^= digtmp[k];
 339         }
 340         tkeylen -= cplen;
 341         i++;
 342         p += cplen;
 343     }
 344     ret = 1;
 345
 346 err:
 347     HMAC_CTX_free(hctx);
 348     HMAC_CTX_free(hctx_tpl);
 349     return ret;
 350 }