1 /* Written by Dr Stephen N Henson (steve (at) openssl.org) for the OpenSSL 2 * project 1999. 3 */ 4 /* ==================================================================== 5 * Copyright (c) 1999 The OpenSSL Project. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * 19 * 3. All advertising materials mentioning features or use of this 20 * software must display the following acknowledgment: 21 * "This product includes software developed by the OpenSSL Project 22 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 23 * 24 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 25 * endorse or promote products derived from this software without 26 * prior written permission. For written permission, please contact 27 * licensing (at) OpenSSL.org. 28 * 29 * 5. Products derived from this software may not be called "OpenSSL" 30 * nor may "OpenSSL" appear in their names without prior written 31 * permission of the OpenSSL Project. 32 * 33 * 6. Redistributions of any form whatsoever must retain the following 34 * acknowledgment: 35 * "This product includes software developed by the OpenSSL Project 36 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 37 * 38 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 39 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 41 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 42 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 47 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 48 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 49 * OF THE POSSIBILITY OF SUCH DAMAGE. 50 * ==================================================================== 51 * 52 * This product includes cryptographic software written by Eric Young 53 * (eay (at) cryptsoft.com). This product includes software written by Tim 54 * Hudson (tjh (at) cryptsoft.com). */ 55 56 #include <openssl/evp.h> 57 58 #include <string.h> 59 60 #include <openssl/hmac.h> 61 62 #include "../internal.h" 63 64 65 int PKCS5_PBKDF2_HMAC(const char *password, size_t password_len, 66 const uint8_t *salt, size_t salt_len, unsigned iterations, 67 const EVP_MD *digest, size_t key_len, uint8_t *out_key) { 68 // See RFC 8018, section 5.2. 69 int ret = 0; 70 size_t md_len = EVP_MD_size(digest); 71 uint32_t i = 1; 72 HMAC_CTX hctx; 73 HMAC_CTX_init(&hctx); 74 75 if (!HMAC_Init_ex(&hctx, password, password_len, digest, NULL)) { 76 goto err; 77 } 78 79 while (key_len > 0) { 80 size_t todo = md_len; 81 if (todo > key_len) { 82 todo = key_len; 83 } 84 85 uint8_t i_buf[4]; 86 i_buf[0] = (uint8_t)((i >> 24) & 0xff); 87 i_buf[1] = (uint8_t)((i >> 16) & 0xff); 88 i_buf[2] = (uint8_t)((i >> 8) & 0xff); 89 i_buf[3] = (uint8_t)(i & 0xff); 90 91 // Compute U_1. 92 uint8_t digest_tmp[EVP_MAX_MD_SIZE]; 93 if (!HMAC_Init_ex(&hctx, NULL, 0, NULL, NULL) || 94 !HMAC_Update(&hctx, salt, salt_len) || 95 !HMAC_Update(&hctx, i_buf, 4) || 96 !HMAC_Final(&hctx, digest_tmp, NULL)) { 97 goto err; 98 } 99 100 OPENSSL_memcpy(out_key, digest_tmp, todo); 101 for (unsigned j = 1; j < iterations; j++) { 102 // Compute the remaining U_* values and XOR. 103 if (!HMAC_Init_ex(&hctx, NULL, 0, NULL, NULL) || 104 !HMAC_Update(&hctx, digest_tmp, md_len) || 105 !HMAC_Final(&hctx, digest_tmp, NULL)) { 106 goto err; 107 } 108 for (size_t k = 0; k < todo; k++) { 109 out_key[k] ^= digest_tmp[k]; 110 } 111 } 112 113 key_len -= todo; 114 out_key += todo; 115 i++; 116 } 117 118 // RFC 8018 describes iterations (c) as being a "positive integer", so a 119 // value of 0 is an error. 120 // 121 // Unfortunately not all consumers of PKCS5_PBKDF2_HMAC() check their return 122 // value, expecting it to succeed and unconditionally using |out_key|. As a 123 // precaution for such callsites in external code, the old behavior of 124 // iterations < 1 being treated as iterations == 1 is preserved, but 125 // additionally an error result is returned. 126 // 127 // TODO(eroman): Figure out how to remove this compatibility hack, or change 128 // the default to something more sensible like 2048. 129 if (iterations == 0) { 130 goto err; 131 } 132 133 ret = 1; 134 135 err: 136 HMAC_CTX_cleanup(&hctx); 137 return ret; 138 } 139 140 int PKCS5_PBKDF2_HMAC_SHA1(const char *password, size_t password_len, 141 const uint8_t *salt, size_t salt_len, 142 unsigned iterations, size_t key_len, 143 uint8_t *out_key) { 144 return PKCS5_PBKDF2_HMAC(password, password_len, salt, salt_len, iterations, 145 EVP_sha1(), key_len, out_key); 146 } 147
