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