1/* 2 * Copyright (c) 2000-2001,2011-2014 Apple Inc. All Rights Reserved. 3 * 4 * The contents of this file constitute Original Code as defined in and are 5 * subject to the Apple Public Source License Version 1.2 (the 'License'). 6 * You may not use this file except in compliance with the License. Please obtain 7 * a copy of the License at http://www.apple.com/publicsource and read it before 8 * using this file. 9 * 10 * This Original Code and all software distributed under the License are 11 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS 12 * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT 13 * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 14 * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the 15 * specific language governing rights and limitations under the License. 16 */ 17 18 19/* 20 File: HmacSha1Legacy.c 21 Contains: HMAC/SHA1, bug-for-bug compatible with BSAFE 4.0. 22 Copyright (c) 2001,2011-2014 Apple Inc. All Rights Reserved. 23*/ 24 25#include "ckconfig.h" 26 27#if CRYPTKIT_HMAC_LEGACY 28 29#include "HmacSha1Legacy.h" 30#include "ckSHA1.h" 31#include <string.h> 32#include <stdlib.h> 33#include <Security/SecBase.h> 34#define kHMACSHA1DigestSize 20 35 36/* XXX These should really be in ckSHA1.h */ 37#define kSHA1DigestSize 20 38#define kSHA1BlockSize 64 39 40/* 41 * bug-for-bug compatible with BSAFE 4.0. See 42 * BSafe/bsource/algs/ahchhmac.c. 43 * 44 * This implementation, and the BSAFE implementation it emulates, work fine 45 * when calculating a MAC in a single update (init, update, final). They 46 * generate nonconforming MACs when performing multiple updates because 47 * the entire algorithm - both inner and outer digests - are performed 48 * in the update() step. As a result, if one e.g. calculates a MAC of 49 * a block of text with one update, and then calculates the MAC over the 50 * same block of text via two updates, different results will obtain.�The 51 * incorrect result from the multiple-update scenario is repeatable if and 52 * only if the same boundaries (same update sizes) are observed on each operation. 53 * 54 * Because all of the data to be MAC'd is in fact protected by both levels of 55 * SHA1, and all of the key bits are used, this nonconforming implementation is 56 * believed to be as strong, cryptographically, as a conforming SHA1HMAC 57 * implementation. 58 */ 59struct hmacLegacyContext { 60 sha1Obj sha1Context; 61 UInt8 k_ipad[kSHA1BlockSize]; 62 UInt8 k_opad[kSHA1BlockSize]; 63}; 64 65hmacLegacyContextRef hmacLegacyAlloc(void) 66{ 67 hmacLegacyContextRef hmac = 68 (hmacLegacyContextRef)malloc(sizeof(struct hmacLegacyContext)); 69 memset(hmac, 0, sizeof(struct hmacLegacyContext)); 70 return hmac; 71} 72 73void hmacLegacyFree( 74 hmacLegacyContextRef hmac) 75{ 76 if(hmac != NULL) { 77 if(hmac->sha1Context != NULL) { 78 sha1Free (hmac->sha1Context); 79 } 80 memset(hmac, 0, sizeof(struct hmacLegacyContext)); 81 free(hmac); 82 } 83} 84 85/* reusable init */ 86OSStatus hmacLegacyInit( 87 hmacLegacyContextRef hmac, 88 const void *keyPtr, 89 UInt32 keyLen) 90{ 91 UInt8 *key; 92 UInt32 byte; 93 94 if(hmac->sha1Context == NULL) { 95 hmac->sha1Context = sha1Alloc(); 96 if(hmac->sha1Context == NULL) { 97 return errSecAllocate; 98 } 99 } 100 else { 101 sha1Reinit(hmac->sha1Context); 102 } 103 /* this implementation requires a 20-byte key */ 104 if (keyLen != kSHA1DigestSize) { 105 /* FIXME */ 106 return errSecParam; 107 } 108 key = (UInt8*)keyPtr; 109 110 /* The HMAC_SHA_1 transform looks like: 111 SHA1 (K XOR opad || SHA1 (K XOR ipad || text)) 112 Where K is a n byte key 113 ipad is the byte 0x36 repeated 64 times. 114 opad is the byte 0x5c repeated 64 times. 115 text is the data being protected. 116 */ 117 /* Copy the key into k_ipad and k_opad while doing the XOR. */ 118 for (byte = 0; byte < keyLen; byte++) 119 { 120 hmac->k_ipad[byte] = key[byte] ^ 0x36; 121 hmac->k_opad[byte] = key[byte] ^ 0x5c; 122 } 123 124 /* Fill the remainder of k_ipad and k_opad with 0 XORed with 125 * appropriate value. */ 126 memset (hmac->k_ipad + keyLen, 0x36, kSHA1BlockSize - keyLen); 127 memset (hmac->k_opad + keyLen, 0x5c, kSHA1BlockSize - keyLen); 128 129 /* remainder happens in update */ 130 return errSecSuccess; 131} 132 133OSStatus hmacLegacyUpdate( 134 hmacLegacyContextRef hmac, 135 const void *textPtr, 136 UInt32 textLen) 137{ 138 UInt8 innerDigest[kSHA1DigestSize]; 139 140 /* compute SHA1(k_ipad || data) ==> innerDigest */ 141 sha1AddData (hmac->sha1Context, hmac->k_ipad, kSHA1BlockSize); 142 sha1AddData (hmac->sha1Context, (UInt8*)textPtr, textLen); 143 memcpy (innerDigest, sha1Digest(hmac->sha1Context), kSHA1DigestSize); 144 145 /* reset context (BSAFE does this implicitly in a final() call) */ 146 sha1Reinit(hmac->sha1Context); 147 148 /* compute SHA1(k_opad || innerDigest) */ 149 sha1AddData (hmac->sha1Context, hmac->k_opad, kSHA1BlockSize); 150 sha1AddData (hmac->sha1Context, innerDigest, kSHA1DigestSize); 151 152 /* if there is another update coming, it gets added in to existing 153 * context; if the next step is a final, the current digest state is used. */ 154 return errSecSuccess; 155} 156 157OSStatus hmacLegacyFinal( 158 hmacLegacyContextRef hmac, 159 void *resultPtr) // caller mallocs, must be HMACSHA1_OUT_SIZE bytes 160{ 161 memcpy (resultPtr, sha1Digest (hmac->sha1Context), kSHA1DigestSize); 162 return errSecSuccess; 163} 164 165#endif /* CRYPTKIT_HMAC_LEGACY */ 166