1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2019, 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 */
57CURLcode 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 */
91CURLcode 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