hmac.c (5087B)
1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) Daniel Stenberg, <daniel@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 https://curl.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 * SPDX-License-Identifier: curl 22 * 23 * RFC2104 Keyed-Hashing for Message Authentication 24 * 25 ***************************************************************************/ 26 27 #include "curl_setup.h" 28 29 #if (defined(USE_CURL_NTLM_CORE) && !defined(USE_WINDOWS_SSPI)) || \ 30 !defined(CURL_DISABLE_AWS) || !defined(CURL_DISABLE_DIGEST_AUTH) || \ 31 defined(USE_SSL) 32 33 #include <curl/curl.h> 34 35 #include "curl_hmac.h" 36 #include "curl_memory.h" 37 #include "curlx/warnless.h" 38 39 /* The last #include file should be: */ 40 #include "memdebug.h" 41 42 /* 43 * Generic HMAC algorithm. 44 * 45 * This module computes HMAC digests based on any hash function. Parameters 46 * and computing procedures are setup dynamically at HMAC computation context 47 * initialization. 48 */ 49 50 static const unsigned char hmac_ipad = 0x36; 51 static const unsigned char hmac_opad = 0x5C; 52 53 struct HMAC_context * 54 Curl_HMAC_init(const struct HMAC_params *hashparams, 55 const unsigned char *key, 56 unsigned int keylen) 57 { 58 size_t i; 59 struct HMAC_context *ctxt; 60 unsigned char *hkey; 61 unsigned char b; 62 63 /* Create HMAC context. */ 64 i = sizeof(*ctxt) + 2 * hashparams->ctxtsize + hashparams->resultlen; 65 ctxt = malloc(i); 66 67 if(!ctxt) 68 return ctxt; 69 70 ctxt->hash = hashparams; 71 ctxt->hashctxt1 = (void *) (ctxt + 1); 72 ctxt->hashctxt2 = (void *) ((char *) ctxt->hashctxt1 + hashparams->ctxtsize); 73 74 /* If the key is too long, replace it by its hash digest. */ 75 if(keylen > hashparams->maxkeylen) { 76 hashparams->hinit(ctxt->hashctxt1); 77 hashparams->hupdate(ctxt->hashctxt1, key, keylen); 78 hkey = (unsigned char *) ctxt->hashctxt2 + hashparams->ctxtsize; 79 hashparams->hfinal(hkey, ctxt->hashctxt1); 80 key = hkey; 81 keylen = hashparams->resultlen; 82 } 83 84 /* Prime the two hash contexts with the modified key. */ 85 hashparams->hinit(ctxt->hashctxt1); 86 hashparams->hinit(ctxt->hashctxt2); 87 88 for(i = 0; i < keylen; i++) { 89 b = (unsigned char)(*key ^ hmac_ipad); 90 hashparams->hupdate(ctxt->hashctxt1, &b, 1); 91 b = (unsigned char)(*key++ ^ hmac_opad); 92 hashparams->hupdate(ctxt->hashctxt2, &b, 1); 93 } 94 95 for(; i < hashparams->maxkeylen; i++) { 96 hashparams->hupdate(ctxt->hashctxt1, &hmac_ipad, 1); 97 hashparams->hupdate(ctxt->hashctxt2, &hmac_opad, 1); 98 } 99 100 /* Done, return pointer to HMAC context. */ 101 return ctxt; 102 } 103 104 int Curl_HMAC_update(struct HMAC_context *ctxt, 105 const unsigned char *ptr, 106 unsigned int len) 107 { 108 /* Update first hash calculation. */ 109 ctxt->hash->hupdate(ctxt->hashctxt1, ptr, len); 110 return 0; 111 } 112 113 114 int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *output) 115 { 116 const struct HMAC_params *hashparams = ctxt->hash; 117 118 /* Do not get output if called with a null parameter: only release 119 storage. */ 120 121 if(!output) 122 output = (unsigned char *) ctxt->hashctxt2 + ctxt->hash->ctxtsize; 123 124 hashparams->hfinal(output, ctxt->hashctxt1); 125 hashparams->hupdate(ctxt->hashctxt2, output, hashparams->resultlen); 126 hashparams->hfinal(output, ctxt->hashctxt2); 127 free(ctxt); 128 return 0; 129 } 130 131 /* 132 * Curl_hmacit() 133 * 134 * This is used to generate a HMAC hash, for the specified input data, given 135 * the specified hash function and key. 136 * 137 * Parameters: 138 * 139 * hashparams [in] - The hash function (Curl_HMAC_MD5). 140 * key [in] - The key to use. 141 * keylen [in] - The length of the key. 142 * buf [in] - The data to encrypt. 143 * buflen [in] - The length of the data. 144 * output [in/out] - The output buffer. 145 * 146 * Returns CURLE_OK on success. 147 */ 148 CURLcode Curl_hmacit(const struct HMAC_params *hashparams, 149 const unsigned char *key, const size_t keylen, 150 const unsigned char *buf, const size_t buflen, 151 unsigned char *output) 152 { 153 struct HMAC_context *ctxt = 154 Curl_HMAC_init(hashparams, key, curlx_uztoui(keylen)); 155 156 if(!ctxt) 157 return CURLE_OUT_OF_MEMORY; 158 159 /* Update the digest with the given challenge */ 160 Curl_HMAC_update(ctxt, buf, curlx_uztoui(buflen)); 161 162 /* Finalise the digest */ 163 Curl_HMAC_final(ctxt, output); 164 165 return CURLE_OK; 166 } 167 168 #endif /* Using NTLM (without SSPI) or AWS */