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