1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 * Copyright (C) Markus Moeller, <markus_moeller@compuserve.com>
10 *
11 * This software is licensed as described in the file COPYING, which
12 * you should have received as part of this distribution. The terms
13 * are also available at https://curl.se/docs/copyright.html.
14 *
15 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
16 * copies of the Software, and permit persons to whom the Software is
17 * furnished to do so, under the terms of the COPYING file.
18 *
19 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
20 * KIND, either express or implied.
21 *
22 * SPDX-License-Identifier: curl
23 *
24 ***************************************************************************/
25
26 #include "curl_setup.h"
27
28 #if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_PROXY)
29
30 #include "curl_gssapi.h"
31 #include "urldata.h"
32 #include "sendf.h"
33 #include "cfilters.h"
34 #include "connect.h"
35 #include "timeval.h"
36 #include "socks.h"
37 #include "warnless.h"
38
39 /* The last 3 #include files should be in this order */
40 #include "curl_printf.h"
41 #include "curl_memory.h"
42 #include "memdebug.h"
43
44 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
45
46 /*
47 * Helper GSS-API error functions.
48 */
check_gss_err(struct Curl_easy * data,OM_uint32 major_status,OM_uint32 minor_status,const char * function)49 static int check_gss_err(struct Curl_easy *data,
50 OM_uint32 major_status,
51 OM_uint32 minor_status,
52 const char *function)
53 {
54 if(GSS_ERROR(major_status)) {
55 OM_uint32 maj_stat, min_stat;
56 OM_uint32 msg_ctx = 0;
57 gss_buffer_desc status_string = GSS_C_EMPTY_BUFFER;
58 char buf[1024];
59 size_t len;
60
61 len = 0;
62 msg_ctx = 0;
63 while(!msg_ctx) {
64 /* convert major status code (GSS-API error) to text */
65 maj_stat = gss_display_status(&min_stat, major_status,
66 GSS_C_GSS_CODE,
67 GSS_C_NULL_OID,
68 &msg_ctx, &status_string);
69 if(maj_stat == GSS_S_COMPLETE) {
70 if(sizeof(buf) > len + status_string.length + 1) {
71 strcpy(buf + len, (char *) status_string.value);
72 len += status_string.length;
73 }
74 gss_release_buffer(&min_stat, &status_string);
75 break;
76 }
77 gss_release_buffer(&min_stat, &status_string);
78 }
79 if(sizeof(buf) > len + 3) {
80 strcpy(buf + len, ".\n");
81 len += 2;
82 }
83 msg_ctx = 0;
84 while(!msg_ctx) {
85 /* convert minor status code (underlying routine error) to text */
86 maj_stat = gss_display_status(&min_stat, minor_status,
87 GSS_C_MECH_CODE,
88 GSS_C_NULL_OID,
89 &msg_ctx, &status_string);
90 if(maj_stat == GSS_S_COMPLETE) {
91 if(sizeof(buf) > len + status_string.length)
92 strcpy(buf + len, (char *) status_string.value);
93 gss_release_buffer(&min_stat, &status_string);
94 break;
95 }
96 gss_release_buffer(&min_stat, &status_string);
97 }
98 failf(data, "GSS-API error: %s failed: %s", function, buf);
99 return 1;
100 }
101
102 return 0;
103 }
104
Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter * cf,struct Curl_easy * data)105 CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
106 struct Curl_easy *data)
107 {
108 struct connectdata *conn = cf->conn;
109 curl_socket_t sock = conn->sock[cf->sockindex];
110 CURLcode code;
111 ssize_t actualread;
112 ssize_t nwritten;
113 int result;
114 OM_uint32 gss_major_status, gss_minor_status, gss_status;
115 OM_uint32 gss_ret_flags;
116 int gss_conf_state, gss_enc;
117 gss_buffer_desc service = GSS_C_EMPTY_BUFFER;
118 gss_buffer_desc gss_send_token = GSS_C_EMPTY_BUFFER;
119 gss_buffer_desc gss_recv_token = GSS_C_EMPTY_BUFFER;
120 gss_buffer_desc gss_w_token = GSS_C_EMPTY_BUFFER;
121 gss_buffer_desc *gss_token = GSS_C_NO_BUFFER;
122 gss_name_t server = GSS_C_NO_NAME;
123 gss_name_t gss_client_name = GSS_C_NO_NAME;
124 unsigned short us_length;
125 char *user = NULL;
126 unsigned char socksreq[4]; /* room for GSS-API exchange header only */
127 const char *serviceptr = data->set.str[STRING_PROXY_SERVICE_NAME] ?
128 data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd";
129 const size_t serviceptr_length = strlen(serviceptr);
130
131 /* GSS-API request looks like
132 * +----+------+-----+----------------+
133 * |VER | MTYP | LEN | TOKEN |
134 * +----+------+----------------------+
135 * | 1 | 1 | 2 | up to 2^16 - 1 |
136 * +----+------+-----+----------------+
137 */
138
139 /* prepare service name */
140 if(strchr(serviceptr, '/')) {
141 service.length = serviceptr_length;
142 service.value = malloc(service.length);
143 if(!service.value)
144 return CURLE_OUT_OF_MEMORY;
145 memcpy(service.value, serviceptr, service.length);
146
147 gss_major_status = gss_import_name(&gss_minor_status, &service,
148 (gss_OID) GSS_C_NULL_OID, &server);
149 }
150 else {
151 service.value = malloc(serviceptr_length +
152 strlen(conn->socks_proxy.host.name) + 2);
153 if(!service.value)
154 return CURLE_OUT_OF_MEMORY;
155 service.length = serviceptr_length +
156 strlen(conn->socks_proxy.host.name) + 1;
157 msnprintf(service.value, service.length + 1, "%s@%s",
158 serviceptr, conn->socks_proxy.host.name);
159
160 gss_major_status = gss_import_name(&gss_minor_status, &service,
161 GSS_C_NT_HOSTBASED_SERVICE, &server);
162 }
163
164 gss_release_buffer(&gss_status, &service); /* clear allocated memory */
165
166 if(check_gss_err(data, gss_major_status,
167 gss_minor_status, "gss_import_name()")) {
168 failf(data, "Failed to create service name.");
169 gss_release_name(&gss_status, &server);
170 return CURLE_COULDNT_CONNECT;
171 }
172
173 (void)curlx_nonblock(sock, FALSE);
174
175 /* As long as we need to keep sending some context info, and there's no */
176 /* errors, keep sending it... */
177 for(;;) {
178 gss_major_status = Curl_gss_init_sec_context(data,
179 &gss_minor_status,
180 &gss_context,
181 server,
182 &Curl_krb5_mech_oid,
183 NULL,
184 gss_token,
185 &gss_send_token,
186 TRUE,
187 &gss_ret_flags);
188
189 if(gss_token != GSS_C_NO_BUFFER)
190 gss_release_buffer(&gss_status, &gss_recv_token);
191 if(check_gss_err(data, gss_major_status,
192 gss_minor_status, "gss_init_sec_context")) {
193 gss_release_name(&gss_status, &server);
194 gss_release_buffer(&gss_status, &gss_recv_token);
195 gss_release_buffer(&gss_status, &gss_send_token);
196 gss_delete_sec_context(&gss_status, &gss_context, NULL);
197 failf(data, "Failed to initial GSS-API token.");
198 return CURLE_COULDNT_CONNECT;
199 }
200
201 if(gss_send_token.length) {
202 socksreq[0] = 1; /* GSS-API subnegotiation version */
203 socksreq[1] = 1; /* authentication message type */
204 us_length = htons((short)gss_send_token.length);
205 memcpy(socksreq + 2, &us_length, sizeof(short));
206
207 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, &code);
208 if(code || (4 != nwritten)) {
209 failf(data, "Failed to send GSS-API authentication request.");
210 gss_release_name(&gss_status, &server);
211 gss_release_buffer(&gss_status, &gss_recv_token);
212 gss_release_buffer(&gss_status, &gss_send_token);
213 gss_delete_sec_context(&gss_status, &gss_context, NULL);
214 return CURLE_COULDNT_CONNECT;
215 }
216
217 nwritten = Curl_conn_cf_send(cf->next, data,
218 (char *)gss_send_token.value,
219 gss_send_token.length, &code);
220 if(code || ((ssize_t)gss_send_token.length != nwritten)) {
221 failf(data, "Failed to send GSS-API authentication token.");
222 gss_release_name(&gss_status, &server);
223 gss_release_buffer(&gss_status, &gss_recv_token);
224 gss_release_buffer(&gss_status, &gss_send_token);
225 gss_delete_sec_context(&gss_status, &gss_context, NULL);
226 return CURLE_COULDNT_CONNECT;
227 }
228
229 }
230
231 gss_release_buffer(&gss_status, &gss_send_token);
232 gss_release_buffer(&gss_status, &gss_recv_token);
233 if(gss_major_status != GSS_S_CONTINUE_NEEDED)
234 break;
235
236 /* analyse response */
237
238 /* GSS-API response looks like
239 * +----+------+-----+----------------+
240 * |VER | MTYP | LEN | TOKEN |
241 * +----+------+----------------------+
242 * | 1 | 1 | 2 | up to 2^16 - 1 |
243 * +----+------+-----+----------------+
244 */
245
246 result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread);
247 if(result || (actualread != 4)) {
248 failf(data, "Failed to receive GSS-API authentication response.");
249 gss_release_name(&gss_status, &server);
250 gss_delete_sec_context(&gss_status, &gss_context, NULL);
251 return CURLE_COULDNT_CONNECT;
252 }
253
254 /* ignore the first (VER) byte */
255 if(socksreq[1] == 255) { /* status / message type */
256 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
257 socksreq[0], socksreq[1]);
258 gss_release_name(&gss_status, &server);
259 gss_delete_sec_context(&gss_status, &gss_context, NULL);
260 return CURLE_COULDNT_CONNECT;
261 }
262
263 if(socksreq[1] != 1) { /* status / message type */
264 failf(data, "Invalid GSS-API authentication response type (%d %d).",
265 socksreq[0], socksreq[1]);
266 gss_release_name(&gss_status, &server);
267 gss_delete_sec_context(&gss_status, &gss_context, NULL);
268 return CURLE_COULDNT_CONNECT;
269 }
270
271 memcpy(&us_length, socksreq + 2, sizeof(short));
272 us_length = ntohs(us_length);
273
274 gss_recv_token.length = us_length;
275 gss_recv_token.value = malloc(us_length);
276 if(!gss_recv_token.value) {
277 failf(data,
278 "Could not allocate memory for GSS-API authentication "
279 "response token.");
280 gss_release_name(&gss_status, &server);
281 gss_delete_sec_context(&gss_status, &gss_context, NULL);
282 return CURLE_OUT_OF_MEMORY;
283 }
284
285 result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value,
286 gss_recv_token.length, &actualread);
287
288 if(result || (actualread != us_length)) {
289 failf(data, "Failed to receive GSS-API authentication token.");
290 gss_release_name(&gss_status, &server);
291 gss_release_buffer(&gss_status, &gss_recv_token);
292 gss_delete_sec_context(&gss_status, &gss_context, NULL);
293 return CURLE_COULDNT_CONNECT;
294 }
295
296 gss_token = &gss_recv_token;
297 }
298
299 gss_release_name(&gss_status, &server);
300
301 /* Everything is good so far, user was authenticated! */
302 gss_major_status = gss_inquire_context(&gss_minor_status, gss_context,
303 &gss_client_name, NULL, NULL, NULL,
304 NULL, NULL, NULL);
305 if(check_gss_err(data, gss_major_status,
306 gss_minor_status, "gss_inquire_context")) {
307 gss_delete_sec_context(&gss_status, &gss_context, NULL);
308 gss_release_name(&gss_status, &gss_client_name);
309 failf(data, "Failed to determine user name.");
310 return CURLE_COULDNT_CONNECT;
311 }
312 gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
313 &gss_send_token, NULL);
314 if(check_gss_err(data, gss_major_status,
315 gss_minor_status, "gss_display_name")) {
316 gss_delete_sec_context(&gss_status, &gss_context, NULL);
317 gss_release_name(&gss_status, &gss_client_name);
318 gss_release_buffer(&gss_status, &gss_send_token);
319 failf(data, "Failed to determine user name.");
320 return CURLE_COULDNT_CONNECT;
321 }
322 user = malloc(gss_send_token.length + 1);
323 if(!user) {
324 gss_delete_sec_context(&gss_status, &gss_context, NULL);
325 gss_release_name(&gss_status, &gss_client_name);
326 gss_release_buffer(&gss_status, &gss_send_token);
327 return CURLE_OUT_OF_MEMORY;
328 }
329
330 memcpy(user, gss_send_token.value, gss_send_token.length);
331 user[gss_send_token.length] = '\0';
332 gss_release_name(&gss_status, &gss_client_name);
333 gss_release_buffer(&gss_status, &gss_send_token);
334 infof(data, "SOCKS5 server authenticated user %s with GSS-API.",user);
335 free(user);
336 user = NULL;
337
338 /* Do encryption */
339 socksreq[0] = 1; /* GSS-API subnegotiation version */
340 socksreq[1] = 2; /* encryption message type */
341
342 gss_enc = 0; /* no data protection */
343 /* do confidentiality protection if supported */
344 if(gss_ret_flags & GSS_C_CONF_FLAG)
345 gss_enc = 2;
346 /* else do integrity protection */
347 else if(gss_ret_flags & GSS_C_INTEG_FLAG)
348 gss_enc = 1;
349
350 infof(data, "SOCKS5 server supports GSS-API %s data protection.",
351 (gss_enc == 0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
352 /* force for the moment to no data protection */
353 gss_enc = 0;
354 /*
355 * Sending the encryption type in clear seems wrong. It should be
356 * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
357 * The NEC reference implementations on which this is based is
358 * therefore at fault
359 *
360 * +------+------+------+.......................+
361 * + ver | mtyp | len | token |
362 * +------+------+------+.......................+
363 * + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
364 * +------+------+------+.......................+
365 *
366 * Where:
367 *
368 * - "ver" is the protocol version number, here 1 to represent the
369 * first version of the SOCKS/GSS-API protocol
370 *
371 * - "mtyp" is the message type, here 2 to represent a protection
372 * -level negotiation message
373 *
374 * - "len" is the length of the "token" field in octets
375 *
376 * - "token" is the GSS-API encapsulated protection level
377 *
378 * The token is produced by encapsulating an octet containing the
379 * required protection level using gss_seal()/gss_wrap() with conf_req
380 * set to FALSE. The token is verified using gss_unseal()/
381 * gss_unwrap().
382 *
383 */
384 if(data->set.socks5_gssapi_nec) {
385 us_length = htons((short)1);
386 memcpy(socksreq + 2, &us_length, sizeof(short));
387 }
388 else {
389 gss_send_token.length = 1;
390 gss_send_token.value = malloc(1);
391 if(!gss_send_token.value) {
392 gss_delete_sec_context(&gss_status, &gss_context, NULL);
393 return CURLE_OUT_OF_MEMORY;
394 }
395 memcpy(gss_send_token.value, &gss_enc, 1);
396
397 gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
398 GSS_C_QOP_DEFAULT, &gss_send_token,
399 &gss_conf_state, &gss_w_token);
400
401 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
402 gss_release_buffer(&gss_status, &gss_send_token);
403 gss_release_buffer(&gss_status, &gss_w_token);
404 gss_delete_sec_context(&gss_status, &gss_context, NULL);
405 failf(data, "Failed to wrap GSS-API encryption value into token.");
406 return CURLE_COULDNT_CONNECT;
407 }
408 gss_release_buffer(&gss_status, &gss_send_token);
409
410 us_length = htons((short)gss_w_token.length);
411 memcpy(socksreq + 2, &us_length, sizeof(short));
412 }
413
414 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, &code);
415 if(code || (4 != nwritten)) {
416 failf(data, "Failed to send GSS-API encryption request.");
417 gss_release_buffer(&gss_status, &gss_w_token);
418 gss_delete_sec_context(&gss_status, &gss_context, NULL);
419 return CURLE_COULDNT_CONNECT;
420 }
421
422 if(data->set.socks5_gssapi_nec) {
423 memcpy(socksreq, &gss_enc, 1);
424 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 1, &code);
425 if(code || ( 1 != nwritten)) {
426 failf(data, "Failed to send GSS-API encryption type.");
427 gss_delete_sec_context(&gss_status, &gss_context, NULL);
428 return CURLE_COULDNT_CONNECT;
429 }
430 }
431 else {
432 nwritten = Curl_conn_cf_send(cf->next, data,
433 (char *)gss_w_token.value,
434 gss_w_token.length, &code);
435 if(code || ((ssize_t)gss_w_token.length != nwritten)) {
436 failf(data, "Failed to send GSS-API encryption type.");
437 gss_release_buffer(&gss_status, &gss_w_token);
438 gss_delete_sec_context(&gss_status, &gss_context, NULL);
439 return CURLE_COULDNT_CONNECT;
440 }
441 gss_release_buffer(&gss_status, &gss_w_token);
442 }
443
444 result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread);
445 if(result || (actualread != 4)) {
446 failf(data, "Failed to receive GSS-API encryption response.");
447 gss_delete_sec_context(&gss_status, &gss_context, NULL);
448 return CURLE_COULDNT_CONNECT;
449 }
450
451 /* ignore the first (VER) byte */
452 if(socksreq[1] == 255) { /* status / message type */
453 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
454 socksreq[0], socksreq[1]);
455 gss_delete_sec_context(&gss_status, &gss_context, NULL);
456 return CURLE_COULDNT_CONNECT;
457 }
458
459 if(socksreq[1] != 2) { /* status / message type */
460 failf(data, "Invalid GSS-API encryption response type (%d %d).",
461 socksreq[0], socksreq[1]);
462 gss_delete_sec_context(&gss_status, &gss_context, NULL);
463 return CURLE_COULDNT_CONNECT;
464 }
465
466 memcpy(&us_length, socksreq + 2, sizeof(short));
467 us_length = ntohs(us_length);
468
469 gss_recv_token.length = us_length;
470 gss_recv_token.value = malloc(gss_recv_token.length);
471 if(!gss_recv_token.value) {
472 gss_delete_sec_context(&gss_status, &gss_context, NULL);
473 return CURLE_OUT_OF_MEMORY;
474 }
475 result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value,
476 gss_recv_token.length, &actualread);
477
478 if(result || (actualread != us_length)) {
479 failf(data, "Failed to receive GSS-API encryptrion type.");
480 gss_release_buffer(&gss_status, &gss_recv_token);
481 gss_delete_sec_context(&gss_status, &gss_context, NULL);
482 return CURLE_COULDNT_CONNECT;
483 }
484
485 if(!data->set.socks5_gssapi_nec) {
486 gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
487 &gss_recv_token, &gss_w_token,
488 0, GSS_C_QOP_DEFAULT);
489
490 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
491 gss_release_buffer(&gss_status, &gss_recv_token);
492 gss_release_buffer(&gss_status, &gss_w_token);
493 gss_delete_sec_context(&gss_status, &gss_context, NULL);
494 failf(data, "Failed to unwrap GSS-API encryption value into token.");
495 return CURLE_COULDNT_CONNECT;
496 }
497 gss_release_buffer(&gss_status, &gss_recv_token);
498
499 if(gss_w_token.length != 1) {
500 failf(data, "Invalid GSS-API encryption response length (%zu).",
501 gss_w_token.length);
502 gss_release_buffer(&gss_status, &gss_w_token);
503 gss_delete_sec_context(&gss_status, &gss_context, NULL);
504 return CURLE_COULDNT_CONNECT;
505 }
506
507 memcpy(socksreq, gss_w_token.value, gss_w_token.length);
508 gss_release_buffer(&gss_status, &gss_w_token);
509 }
510 else {
511 if(gss_recv_token.length != 1) {
512 failf(data, "Invalid GSS-API encryption response length (%zu).",
513 gss_recv_token.length);
514 gss_release_buffer(&gss_status, &gss_recv_token);
515 gss_delete_sec_context(&gss_status, &gss_context, NULL);
516 return CURLE_COULDNT_CONNECT;
517 }
518
519 memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
520 gss_release_buffer(&gss_status, &gss_recv_token);
521 }
522
523 (void)curlx_nonblock(sock, TRUE);
524
525 infof(data, "SOCKS5 access with%s protection granted.",
526 (socksreq[0] == 0)?"out GSS-API data":
527 ((socksreq[0] == 1)?" GSS-API integrity":" GSS-API confidentiality"));
528
529 conn->socks5_gssapi_enctype = socksreq[0];
530 if(socksreq[0] == 0)
531 gss_delete_sec_context(&gss_status, &gss_context, NULL);
532
533 return CURLE_OK;
534 }
535
536 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */
537