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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2016, 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.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  */
Curl_auth_decode_cram_md5_message(const char * chlg64,char ** outptr,size_t * outlen)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  * passwdp [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  */
Curl_auth_create_cram_md5_message(struct Curl_easy * data,const char * chlg,const char * userp,const char * passwdp,char ** outptr,size_t * outlen)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