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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 1998 - 2016, 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 https://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  * RFC2195 CRAM-MD5 authentication
     22  *
     23  ***************************************************************************/
     24 
     25 #include "curl_setup.h"
     26 
     27 #if !defined(CURL_DISABLE_CRYPTO_AUTH)
     28 
     29 #include <curl/curl.h>
     30 #include "urldata.h"
     31 
     32 #include "vauth/vauth.h"
     33 #include "curl_base64.h"
     34 #include "curl_hmac.h"
     35 #include "curl_md5.h"
     36 #include "warnless.h"
     37 #include "curl_printf.h"
     38 
     39 /* The last #include files should be: */
     40 #include "curl_memory.h"
     41 #include "memdebug.h"
     42 
     43 /*
     44  * Curl_auth_decode_cram_md5_message()
     45  *
     46  * This is used to decode an already encoded CRAM-MD5 challenge message.
     47  *
     48  * Parameters:
     49  *
     50  * chlg64  [in]     - The base64 encoded challenge message.
     51  * outptr  [in/out] - The address where a pointer to newly allocated memory
     52  *                    holding the result will be stored upon completion.
     53  * outlen  [out]    - The length of the output message.
     54  *
     55  * Returns CURLE_OK on success.
     56  */
     57 CURLcode Curl_auth_decode_cram_md5_message(const char *chlg64, char **outptr,
     58                                            size_t *outlen)
     59 {
     60   CURLcode result = CURLE_OK;
     61   size_t chlg64len = strlen(chlg64);
     62 
     63   *outptr = NULL;
     64   *outlen = 0;
     65 
     66   /* Decode the challenge if necessary */
     67   if(chlg64len && *chlg64 != '=')
     68     result = Curl_base64_decode(chlg64, (unsigned char **) outptr, outlen);
     69 
     70   return result;
     71 }
     72 
     73 /*
     74  * Curl_auth_create_cram_md5_message()
     75  *
     76  * This is used to generate an already encoded CRAM-MD5 response message ready
     77  * for sending to the recipient.
     78  *
     79  * Parameters:
     80  *
     81  * data    [in]     - The session handle.
     82  * chlg    [in]     - The challenge.
     83  * userp   [in]     - The user name.
     84  * passdwp [in]     - The user's password.
     85  * outptr  [in/out] - The address where a pointer to newly allocated memory
     86  *                    holding the result will be stored upon completion.
     87  * outlen  [out]    - The length of the output message.
     88  *
     89  * Returns CURLE_OK on success.
     90  */
     91 CURLcode Curl_auth_create_cram_md5_message(struct Curl_easy *data,
     92                                            const char *chlg,
     93                                            const char *userp,
     94                                            const char *passwdp,
     95                                            char **outptr, size_t *outlen)
     96 {
     97   CURLcode result = CURLE_OK;
     98   size_t chlglen = 0;
     99   HMAC_context *ctxt;
    100   unsigned char digest[MD5_DIGEST_LEN];
    101   char *response;
    102 
    103   if(chlg)
    104     chlglen = strlen(chlg);
    105 
    106   /* Compute the digest using the password as the key */
    107   ctxt = Curl_HMAC_init(Curl_HMAC_MD5,
    108                         (const unsigned char *) passwdp,
    109                         curlx_uztoui(strlen(passwdp)));
    110   if(!ctxt)
    111     return CURLE_OUT_OF_MEMORY;
    112 
    113   /* Update the digest with the given challenge */
    114   if(chlglen > 0)
    115     Curl_HMAC_update(ctxt, (const unsigned char *) chlg,
    116                      curlx_uztoui(chlglen));
    117 
    118   /* Finalise the digest */
    119   Curl_HMAC_final(ctxt, digest);
    120 
    121   /* Generate the response */
    122   response = aprintf(
    123     "%s %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
    124     userp, digest[0], digest[1], digest[2], digest[3], digest[4],
    125     digest[5], digest[6], digest[7], digest[8], digest[9], digest[10],
    126     digest[11], digest[12], digest[13], digest[14], digest[15]);
    127   if(!response)
    128     return CURLE_OUT_OF_MEMORY;
    129 
    130   /* Base64 encode the response */
    131   result = Curl_base64_encode(data, response, 0, outptr, outlen);
    132 
    133   free(response);
    134 
    135   return result;
    136 }
    137 
    138 #endif /* !CURL_DISABLE_CRYPTO_AUTH */
    139