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  * RFC4178 Simple and Protected GSS-API Negotiation Mechanism
22  *
23  ***************************************************************************/
24 
25 #include "curl_setup.h"
26 
27 #if defined(HAVE_GSSAPI) && defined(USE_SPNEGO)
28 
29 #include <curl/curl.h>
30 
31 #include "vauth/vauth.h"
32 #include "urldata.h"
33 #include "curl_base64.h"
34 #include "curl_gssapi.h"
35 #include "warnless.h"
36 #include "curl_multibyte.h"
37 #include "sendf.h"
38 
39 /* The last #include files should be: */
40 #include "curl_memory.h"
41 #include "memdebug.h"
42 
43 /*
44  * Curl_auth_is_spnego_supported()
45  *
46  * This is used to evaluate if SPNEGO (Negotiate) is supported.
47  *
48  * Parameters: None
49  *
50  * Returns TRUE if Negotiate supported by the GSS-API library.
51  */
Curl_auth_is_spnego_supported(void)52 bool Curl_auth_is_spnego_supported(void)
53 {
54   return TRUE;
55 }
56 
57 /*
58  * Curl_auth_decode_spnego_message()
59  *
60  * This is used to decode an already encoded SPNEGO (Negotiate) challenge
61  * message.
62  *
63  * Parameters:
64  *
65  * data        [in]     - The session handle.
66  * userp       [in]     - The user name in the format User or Domain\User.
67  * passwdp     [in]     - The user's password.
68  * service     [in]     - The service type such as http, smtp, pop or imap.
69  * host        [in]     - The host name.
70  * chlg64      [in]     - The optional base64 encoded challenge message.
71  * nego        [in/out] - The Negotiate data struct being used and modified.
72  *
73  * Returns CURLE_OK on success.
74  */
Curl_auth_decode_spnego_message(struct Curl_easy * data,const char * user,const char * password,const char * service,const char * host,const char * chlg64,struct negotiatedata * nego)75 CURLcode Curl_auth_decode_spnego_message(struct Curl_easy *data,
76                                          const char *user,
77                                          const char *password,
78                                          const char *service,
79                                          const char *host,
80                                          const char *chlg64,
81                                          struct negotiatedata *nego)
82 {
83   CURLcode result = CURLE_OK;
84   size_t chlglen = 0;
85   unsigned char *chlg = NULL;
86   OM_uint32 major_status;
87   OM_uint32 minor_status;
88   OM_uint32 unused_status;
89   gss_buffer_desc spn_token = GSS_C_EMPTY_BUFFER;
90   gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
91   gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
92 
93   (void) user;
94   (void) password;
95 
96   if(nego->context && nego->status == GSS_S_COMPLETE) {
97     /* We finished successfully our part of authentication, but server
98      * rejected it (since we're again here). Exit with an error since we
99      * can't invent anything better */
100     Curl_auth_cleanup_spnego(nego);
101     return CURLE_LOGIN_DENIED;
102   }
103 
104   if(!nego->spn) {
105     /* Generate our SPN */
106     char *spn = Curl_auth_build_spn(service, NULL, host);
107     if(!spn)
108       return CURLE_OUT_OF_MEMORY;
109 
110     /* Populate the SPN structure */
111     spn_token.value = spn;
112     spn_token.length = strlen(spn);
113 
114     /* Import the SPN */
115     major_status = gss_import_name(&minor_status, &spn_token,
116                                    GSS_C_NT_HOSTBASED_SERVICE,
117                                    &nego->spn);
118     if(GSS_ERROR(major_status)) {
119       Curl_gss_log_error(data, "gss_import_name() failed: ",
120                          major_status, minor_status);
121 
122       free(spn);
123 
124       return CURLE_AUTH_ERROR;
125     }
126 
127     free(spn);
128   }
129 
130   if(chlg64 && *chlg64) {
131     /* Decode the base-64 encoded challenge message */
132     if(*chlg64 != '=') {
133       result = Curl_base64_decode(chlg64, &chlg, &chlglen);
134       if(result)
135         return result;
136     }
137 
138     /* Ensure we have a valid challenge message */
139     if(!chlg) {
140       infof(data, "SPNEGO handshake failure (empty challenge message)\n");
141 
142       return CURLE_BAD_CONTENT_ENCODING;
143     }
144 
145     /* Setup the challenge "input" security buffer */
146     input_token.value = chlg;
147     input_token.length = chlglen;
148   }
149 
150   /* Generate our challenge-response message */
151   major_status = Curl_gss_init_sec_context(data,
152                                            &minor_status,
153                                            &nego->context,
154                                            nego->spn,
155                                            &Curl_spnego_mech_oid,
156                                            GSS_C_NO_CHANNEL_BINDINGS,
157                                            &input_token,
158                                            &output_token,
159                                            TRUE,
160                                            NULL);
161 
162   /* Free the decoded challenge as it is not required anymore */
163   Curl_safefree(input_token.value);
164 
165   nego->status = major_status;
166   if(GSS_ERROR(major_status)) {
167     if(output_token.value)
168       gss_release_buffer(&unused_status, &output_token);
169 
170     Curl_gss_log_error(data, "gss_init_sec_context() failed: ",
171                        major_status, minor_status);
172 
173     return CURLE_AUTH_ERROR;
174   }
175 
176   if(!output_token.value || !output_token.length) {
177     if(output_token.value)
178       gss_release_buffer(&unused_status, &output_token);
179 
180     return CURLE_AUTH_ERROR;
181   }
182 
183   /* Free previous token */
184   if(nego->output_token.length && nego->output_token.value)
185     gss_release_buffer(&unused_status, &nego->output_token);
186 
187   nego->output_token = output_token;
188 
189   return CURLE_OK;
190 }
191 
192 /*
193  * Curl_auth_create_spnego_message()
194  *
195  * This is used to generate an already encoded SPNEGO (Negotiate) response
196  * message ready for sending to the recipient.
197  *
198  * Parameters:
199  *
200  * data        [in]     - The session handle.
201  * nego        [in/out] - The Negotiate data struct being used and modified.
202  * outptr      [in/out] - The address where a pointer to newly allocated memory
203  *                        holding the result will be stored upon completion.
204  * outlen      [out]    - The length of the output message.
205  *
206  * Returns CURLE_OK on success.
207  */
Curl_auth_create_spnego_message(struct Curl_easy * data,struct negotiatedata * nego,char ** outptr,size_t * outlen)208 CURLcode Curl_auth_create_spnego_message(struct Curl_easy *data,
209                                          struct negotiatedata *nego,
210                                          char **outptr, size_t *outlen)
211 {
212   CURLcode result;
213   OM_uint32 minor_status;
214 
215   /* Base64 encode the already generated response */
216   result = Curl_base64_encode(data,
217                               nego->output_token.value,
218                               nego->output_token.length,
219                               outptr, outlen);
220 
221   if(result) {
222     gss_release_buffer(&minor_status, &nego->output_token);
223     nego->output_token.value = NULL;
224     nego->output_token.length = 0;
225 
226     return result;
227   }
228 
229   if(!*outptr || !*outlen) {
230     gss_release_buffer(&minor_status, &nego->output_token);
231     nego->output_token.value = NULL;
232     nego->output_token.length = 0;
233 
234     return CURLE_REMOTE_ACCESS_DENIED;
235   }
236 
237   return CURLE_OK;
238 }
239 
240 /*
241  * Curl_auth_cleanup_spnego()
242  *
243  * This is used to clean up the SPNEGO (Negotiate) specific data.
244  *
245  * Parameters:
246  *
247  * nego     [in/out] - The Negotiate data struct being cleaned up.
248  *
249  */
Curl_auth_cleanup_spnego(struct negotiatedata * nego)250 void Curl_auth_cleanup_spnego(struct negotiatedata *nego)
251 {
252   OM_uint32 minor_status;
253 
254   /* Free our security context */
255   if(nego->context != GSS_C_NO_CONTEXT) {
256     gss_delete_sec_context(&minor_status, &nego->context, GSS_C_NO_BUFFER);
257     nego->context = GSS_C_NO_CONTEXT;
258   }
259 
260   /* Free the output token */
261   if(nego->output_token.value) {
262     gss_release_buffer(&minor_status, &nego->output_token);
263     nego->output_token.value = NULL;
264     nego->output_token.length = 0;
265 
266   }
267 
268   /* Free the SPN */
269   if(nego->spn != GSS_C_NO_NAME) {
270     gss_release_name(&minor_status, &nego->spn);
271     nego->spn = GSS_C_NO_NAME;
272   }
273 
274   /* Reset any variables */
275   nego->status = 0;
276   nego->noauthpersist = FALSE;
277   nego->havenoauthpersist = FALSE;
278   nego->havenegdata = FALSE;
279   nego->havemultiplerequests = FALSE;
280 }
281 
282 #endif /* HAVE_GSSAPI && USE_SPNEGO */
283