| 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 - 2018, Daniel Stenberg, <[email protected]>, 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/curl.h>
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| 30 |
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| 31 | #include "curl_hmac.h"
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| 32 | #include "curl_memory.h"
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| 33 |
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| 34 | /* The last #include file should be: */
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| 35 | #include "memdebug.h"
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| 36 |
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| 37 | /*
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| 38 | * Generic HMAC algorithm.
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| 39 | *
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| 40 | * This module computes HMAC digests based on any hash function. Parameters
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| 41 | * and computing procedures are set-up dynamically at HMAC computation
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| 42 | * context initialisation.
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| 43 | */
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| 44 |
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| 45 | static const unsigned char hmac_ipad = 0x36;
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| 46 | static const unsigned char hmac_opad = 0x5C;
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| 47 |
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| 48 |
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| 49 |
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| 50 | HMAC_context *
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| 51 | Curl_HMAC_init(const HMAC_params * hashparams,
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| 52 | const unsigned char *key,
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| 53 | unsigned int keylen)
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| 54 | {
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| 55 | size_t i;
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| 56 | HMAC_context *ctxt;
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| 57 | unsigned char *hkey;
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| 58 | unsigned char b;
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| 59 |
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| 60 | /* Create HMAC context. */
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| 61 | i = sizeof(*ctxt) + 2 * hashparams->hmac_ctxtsize +
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| 62 | hashparams->hmac_resultlen;
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| 63 | ctxt = malloc(i);
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| 64 |
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| 65 | if(!ctxt)
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| 66 | return ctxt;
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| 67 |
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| 68 | ctxt->hmac_hash = hashparams;
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| 69 | ctxt->hmac_hashctxt1 = (void *) (ctxt + 1);
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| 70 | ctxt->hmac_hashctxt2 = (void *) ((char *) ctxt->hmac_hashctxt1 +
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| 71 | hashparams->hmac_ctxtsize);
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| 72 |
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| 73 | /* If the key is too long, replace it by its hash digest. */
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| 74 | if(keylen > hashparams->hmac_maxkeylen) {
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| 75 | (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
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| 76 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, key, keylen);
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| 77 | hkey = (unsigned char *) ctxt->hmac_hashctxt2 + hashparams->hmac_ctxtsize;
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| 78 | (*hashparams->hmac_hfinal)(hkey, ctxt->hmac_hashctxt1);
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| 79 | key = hkey;
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| 80 | keylen = hashparams->hmac_resultlen;
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| 81 | }
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| 82 |
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| 83 | /* Prime the two hash contexts with the modified key. */
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| 84 | (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt1);
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| 85 | (*hashparams->hmac_hinit)(ctxt->hmac_hashctxt2);
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| 86 |
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| 87 | for(i = 0; i < keylen; i++) {
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| 88 | b = (unsigned char)(*key ^ hmac_ipad);
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| 89 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &b, 1);
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| 90 | b = (unsigned char)(*key++ ^ hmac_opad);
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| 91 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &b, 1);
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| 92 | }
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| 93 |
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| 94 | for(; i < hashparams->hmac_maxkeylen; i++) {
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| 95 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt1, &hmac_ipad, 1);
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| 96 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2, &hmac_opad, 1);
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| 97 | }
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| 98 |
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| 99 | /* Done, return pointer to HMAC context. */
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| 100 | return ctxt;
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| 101 | }
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| 102 |
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| 103 | int Curl_HMAC_update(HMAC_context * ctxt,
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| 104 | const unsigned char *data,
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| 105 | unsigned int len)
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| 106 | {
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| 107 | /* Update first hash calculation. */
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| 108 | (*ctxt->hmac_hash->hmac_hupdate)(ctxt->hmac_hashctxt1, data, len);
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| 109 | return 0;
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| 110 | }
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| 111 |
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| 112 |
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| 113 | int Curl_HMAC_final(HMAC_context *ctxt, unsigned char *result)
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| 114 | {
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| 115 | const HMAC_params * hashparams = ctxt->hmac_hash;
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| 116 |
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| 117 | /* Do not get result if called with a null parameter: only release
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| 118 | storage. */
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| 119 |
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| 120 | if(!result)
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| 121 | result = (unsigned char *) ctxt->hmac_hashctxt2 +
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| 122 | ctxt->hmac_hash->hmac_ctxtsize;
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| 123 |
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| 124 | (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt1);
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| 125 | (*hashparams->hmac_hupdate)(ctxt->hmac_hashctxt2,
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| 126 | result, hashparams->hmac_resultlen);
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| 127 | (*hashparams->hmac_hfinal)(result, ctxt->hmac_hashctxt2);
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| 128 | free((char *) ctxt);
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| 129 | return 0;
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| 130 | }
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| 131 |
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| 132 | #endif /* CURL_DISABLE_CRYPTO_AUTH */
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