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      1 /*-
      2  * Copyright 2005,2007,2009 Colin Percival
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  */
     26 
     27 #include <limits.h>
     28 #include <stdint.h>
     29 #include <stdlib.h>
     30 #include <string.h>
     31 
     32 #include <sys/types.h>
     33 
     34 #include "core.h"
     35 #include "crypto_auth_hmacsha256.h"
     36 #include "crypto_pwhash_scryptsalsa208sha256.h"
     37 #include "pbkdf2-sha256.h"
     38 #include "private/common.h"
     39 #include "utils.h"
     40 
     41 /**
     42  * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
     43  * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
     44  * write the output to buf.  The value dkLen must be at most 32 * (2^32 - 1).
     45  */
     46 void
     47 PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, const uint8_t *salt,
     48               size_t saltlen, uint64_t c, uint8_t *buf, size_t dkLen)
     49 {
     50     crypto_auth_hmacsha256_state PShctx, hctx;
     51     size_t                       i;
     52     uint8_t                      ivec[4];
     53     uint8_t                      U[32];
     54     uint8_t                      T[32];
     55     uint64_t                     j;
     56     int                          k;
     57     size_t                       clen;
     58 
     59 #if SIZE_MAX > 0x1fffffffe0ULL
     60     COMPILER_ASSERT(crypto_pwhash_scryptsalsa208sha256_BYTES_MAX
     61                     <= 0x1fffffffe0ULL);
     62     if (dkLen > 0x1fffffffe0ULL) {
     63         sodium_misuse(); /* LCOV_EXCL_LINE */
     64     }
     65 #endif
     66     crypto_auth_hmacsha256_init(&PShctx, passwd, passwdlen);
     67     crypto_auth_hmacsha256_update(&PShctx, salt, saltlen);
     68 
     69     for (i = 0; i * 32 < dkLen; i++) {
     70         STORE32_BE(ivec, (uint32_t)(i + 1));
     71         memcpy(&hctx, &PShctx, sizeof(crypto_auth_hmacsha256_state));
     72         crypto_auth_hmacsha256_update(&hctx, ivec, 4);
     73         crypto_auth_hmacsha256_final(&hctx, U);
     74 
     75         memcpy(T, U, 32);
     76         /* LCOV_EXCL_START */
     77         for (j = 2; j <= c; j++) {
     78             crypto_auth_hmacsha256_init(&hctx, passwd, passwdlen);
     79             crypto_auth_hmacsha256_update(&hctx, U, 32);
     80             crypto_auth_hmacsha256_final(&hctx, U);
     81 
     82             for (k = 0; k < 32; k++) {
     83                 T[k] ^= U[k];
     84             }
     85         }
     86         /* LCOV_EXCL_STOP */
     87 
     88         clen = dkLen - i * 32;
     89         if (clen > 32) {
     90             clen = 32;
     91         }
     92         memcpy(&buf[i * 32], T, clen);
     93     }
     94     sodium_memzero((void *) &PShctx, sizeof PShctx);
     95 }
     96