1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel (at) haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at http://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 * RFC2104 Keyed-Hashing for Message Authentication 22 * 23 ***************************************************************************/ 24 25 #include "curl_setup.h" 26 27 #ifndef CURL_DISABLE_CRYPTO_AUTH 28 29 #include "curl_hmac.h" 30 #include "curl_memory.h" 31 /* The last #include file should be: */ 32 #include "memdebug.h" 33 34 /* 35 * Generic HMAC algorithm. 36 * 37 * This module computes HMAC digests based on any hash function. Parameters 38 * and computing procedures are set-up dynamically at HMAC computation 39 * context initialisation. 40 */ 41 42 static const unsigned char hmac_ipad = 0x36; 43 static const unsigned char hmac_opad = 0x5C; 44 45 46 47 HMAC_context * 48 Curl_HMAC_init(const HMAC_params * hashparams, 49 const unsigned char * key, 50 unsigned int keylen) 51 { 52 size_t i; 53 HMAC_context * ctxt; 54 unsigned char * hkey; 55 unsigned char b; 56 57 /* Create HMAC context. */ 58 i = sizeof *ctxt + 2 * hashparams->hmac_ctxtsize + 59 hashparams->hmac_resultlen; 60 ctxt = malloc(i); 61 62 if(!ctxt) 63 return ctxt; 64 65 ctxt->hmac_hash = hashparams; 66 ctxt->hmac_hashctxt1 = (void *) (ctxt + 1); 67 ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 + 68 hashparams->hmac_ctxtsize); 69 70 /* If the key is too long, replace it by its hash digest. */ 71 if(keylen > hashparams->hmac_maxkeylen) { 72 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1); 73 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen); 74 hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize; 75 (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1); 76 key = hkey; 77 keylen = hashparams->hmac_resultlen; 78 } 79 80 /* Prime the two hash contexts with the modified key. */ 81 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1); 82 (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2); 83 84 for(i = 0; i < keylen; i++) { 85 b = (unsigned char)(*key ^ hmac_ipad); 86 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1); 87 b = (unsigned char)(*key++ ^ hmac_opad); 88 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1); 89 } 90 91 for(; i < hashparams->hmac_maxkeylen; i++) { 92 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1); 93 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1); 94 } 95 96 /* Done, return pointer to HMAC context. */ 97 return ctxt; 98 } 99 100 int Curl_HMAC_update(HMAC_context * ctxt, 101 const unsigned char * data, 102 unsigned int len) 103 { 104 /* Update first hash calculation. */ 105 (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len); 106 return 0; 107 } 108 109 110 int Curl_HMAC_final(HMAC_context * ctxt, unsigned char * result) 111 { 112 const HMAC_params * hashparams = ctxt->hmac_hash; 113 114 /* Do not get result if called with a null parameter: only release 115 storage. */ 116 117 if(!result) 118 result = (unsigned char *) ctxt->hmac_hashctxt2 + 119 ctxt->hmac_hash->hmac_ctxtsize; 120 121 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1); 122 (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, 123 result, hashparams->hmac_resultlen); 124 (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2); 125 free((char *) ctxt); 126 return 0; 127 } 128 129 #endif /* CURL_DISABLE_CRYPTO_AUTH */ 130
