summaryrefslogtreecommitdiff
path: root/libs/libcurl/src/vauth/cram.c
blob: 04438fa74075bafffb003878d1f6e65d7e09b642 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * RFC2195 CRAM-MD5 authentication
 *
 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_CRYPTO_AUTH)

#include <curl/curl.h>
#include "urldata.h"

#include "vauth/vauth.h"
#include "curl_base64.h"
#include "curl_hmac.h"
#include "curl_md5.h"
#include "warnless.h"
#include "curl_printf.h"

/* The last #include files should be: */
#include "curl_memory.h"
#include "memdebug.h"

/*
 * Curl_auth_decode_cram_md5_message()
 *
 * This is used to decode an already encoded CRAM-MD5 challenge message.
 *
 * Parameters:
 *
 * chlg64  [in]     - The base64 encoded challenge message.
 * outptr  [in/out] - The address where a pointer to newly allocated memory
 *                    holding the result will be stored upon completion.
 * outlen  [out]    - The length of the output message.
 *
 * Returns CURLE_OK on success.
 */
CURLcode Curl_auth_decode_cram_md5_message(const char *chlg64, char **outptr,
                                           size_t *outlen)
{
  CURLcode result = CURLE_OK;
  size_t chlg64len = strlen(chlg64);

  *outptr = NULL;
  *outlen = 0;

  /* Decode the challenge if necessary */
  if(chlg64len && *chlg64 != '=')
    result = Curl_base64_decode(chlg64, (unsigned char **) outptr, outlen);

  return result;
}

/*
 * Curl_auth_create_cram_md5_message()
 *
 * This is used to generate an already encoded CRAM-MD5 response message ready
 * for sending to the recipient.
 *
 * Parameters:
 *
 * data    [in]     - The session handle.
 * chlg    [in]     - The challenge.
 * userp   [in]     - The user name.
 * passwdp [in]     - The user's password.
 * outptr  [in/out] - The address where a pointer to newly allocated memory
 *                    holding the result will be stored upon completion.
 * outlen  [out]    - The length of the output message.
 *
 * Returns CURLE_OK on success.
 */
CURLcode Curl_auth_create_cram_md5_message(struct Curl_easy *data,
                                           const char *chlg,
                                           const char *userp,
                                           const char *passwdp,
                                           char **outptr, size_t *outlen)
{
  CURLcode result = CURLE_OK;
  size_t chlglen = 0;
  HMAC_context *ctxt;
  unsigned char digest[MD5_DIGEST_LEN];
  char *response;

  if(chlg)
    chlglen = strlen(chlg);

  /* Compute the digest using the password as the key */
  ctxt = Curl_HMAC_init(Curl_HMAC_MD5,
                        (const unsigned char *) passwdp,
                        curlx_uztoui(strlen(passwdp)));
  if(!ctxt)
    return CURLE_OUT_OF_MEMORY;

  /* Update the digest with the given challenge */
  if(chlglen > 0)
    Curl_HMAC_update(ctxt, (const unsigned char *) chlg,
                     curlx_uztoui(chlglen));

  /* Finalise the digest */
  Curl_HMAC_final(ctxt, digest);

  /* Generate the response */
  response = aprintf(
    "%s %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
    userp, digest[0], digest[1], digest[2], digest[3], digest[4],
    digest[5], digest[6], digest[7], digest[8], digest[9], digest[10],
    digest[11], digest[12], digest[13], digest[14], digest[15]);
  if(!response)
    return CURLE_OUT_OF_MEMORY;

  /* Base64 encode the response */
  result = Curl_base64_encode(data, response, 0, outptr, outlen);

  free(response);

  return result;
}

#endif /* !CURL_DISABLE_CRYPTO_AUTH */