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 #include "strdup.h"
39
40 /* The last 3 #include files should be in this order */
41 #include "curl_printf.h"
42 #include "curl_memory.h"
43 #include "memdebug.h"
44
45 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
46
47 /*
48 * Helper GSS-API error functions.
49 */
check_gss_err(struct Curl_easy *data, OM_uint32 major_status, OM_uint32 minor_status, const char *function)50 static int check_gss_err(struct Curl_easy *data,
51 OM_uint32 major_status,
52 OM_uint32 minor_status,
53 const char *function)
54 {
55 if(GSS_ERROR(major_status)) {
56 OM_uint32 maj_stat, min_stat;
57 OM_uint32 msg_ctx = 0;
58 gss_buffer_desc status_string = GSS_C_EMPTY_BUFFER;
59 char buf[1024];
60 size_t len;
61
62 len = 0;
63 msg_ctx = 0;
64 while(!msg_ctx) {
65 /* convert major status code (GSS-API error) to text */
66 maj_stat = gss_display_status(&min_stat, major_status,
67 GSS_C_GSS_CODE,
68 GSS_C_NULL_OID,
69 &msg_ctx, &status_string);
70 if(maj_stat == GSS_S_COMPLETE) {
71 if(sizeof(buf) > len + status_string.length + 1) {
72 strcpy(buf + len, (char *) status_string.value);
73 len += status_string.length;
74 }
75 gss_release_buffer(&min_stat, &status_string);
76 break;
77 }
78 gss_release_buffer(&min_stat, &status_string);
79 }
80 if(sizeof(buf) > len + 3) {
81 strcpy(buf + len, ".\n");
82 len += 2;
83 }
84 msg_ctx = 0;
85 while(!msg_ctx) {
86 /* convert minor status code (underlying routine error) to text */
87 maj_stat = gss_display_status(&min_stat, minor_status,
88 GSS_C_MECH_CODE,
89 GSS_C_NULL_OID,
90 &msg_ctx, &status_string);
91 if(maj_stat == GSS_S_COMPLETE) {
92 if(sizeof(buf) > len + status_string.length)
93 strcpy(buf + len, (char *) status_string.value);
94 gss_release_buffer(&min_stat, &status_string);
95 break;
96 }
97 gss_release_buffer(&min_stat, &status_string);
98 }
99 failf(data, "GSS-API error: %s failed: %s", function, buf);
100 return 1;
101 }
102
103 return 0;
104 }
105
Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf, struct Curl_easy *data)106 CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
107 struct Curl_easy *data)
108 {
109 struct connectdata *conn = cf->conn;
110 curl_socket_t sock = conn->sock[cf->sockindex];
111 CURLcode code;
112 ssize_t actualread;
113 ssize_t nwritten;
114 int result;
115 OM_uint32 gss_major_status, gss_minor_status, gss_status;
116 OM_uint32 gss_ret_flags;
117 int gss_conf_state, gss_enc;
118 gss_buffer_desc service = GSS_C_EMPTY_BUFFER;
119 gss_buffer_desc gss_send_token = GSS_C_EMPTY_BUFFER;
120 gss_buffer_desc gss_recv_token = GSS_C_EMPTY_BUFFER;
121 gss_buffer_desc gss_w_token = GSS_C_EMPTY_BUFFER;
122 gss_buffer_desc *gss_token = GSS_C_NO_BUFFER;
123 gss_name_t server = GSS_C_NO_NAME;
124 gss_name_t gss_client_name = GSS_C_NO_NAME;
125 unsigned short us_length;
126 char *user = NULL;
127 unsigned char socksreq[4]; /* room for GSS-API exchange header only */
128 const char *serviceptr = data->set.str[STRING_PROXY_SERVICE_NAME] ?
129 data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd";
130 const size_t serviceptr_length = strlen(serviceptr);
131
132 /* GSS-API request looks like
133 * +----+------+-----+----------------+
134 * |VER | MTYP | LEN | TOKEN |
135 * +----+------+----------------------+
136 * | 1 | 1 | 2 | up to 2^16 - 1 |
137 * +----+------+-----+----------------+
138 */
139
140 /* prepare service name */
141 if(strchr(serviceptr, '/')) {
142 service.length = serviceptr_length;
143 service.value = Curl_memdup(serviceptr, service.length);
144 if(!service.value)
145 return CURLE_OUT_OF_MEMORY;
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 = Curl_memdup(&gss_enc, 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
396 gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
397 GSS_C_QOP_DEFAULT, &gss_send_token,
398 &gss_conf_state, &gss_w_token);
399
400 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
401 gss_release_buffer(&gss_status, &gss_send_token);
402 gss_release_buffer(&gss_status, &gss_w_token);
403 gss_delete_sec_context(&gss_status, &gss_context, NULL);
404 failf(data, "Failed to wrap GSS-API encryption value into token.");
405 return CURLE_COULDNT_CONNECT;
406 }
407 gss_release_buffer(&gss_status, &gss_send_token);
408
409 us_length = htons((short)gss_w_token.length);
410 memcpy(socksreq + 2, &us_length, sizeof(short));
411 }
412
413 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, &code);
414 if(code || (4 != nwritten)) {
415 failf(data, "Failed to send GSS-API encryption request.");
416 gss_release_buffer(&gss_status, &gss_w_token);
417 gss_delete_sec_context(&gss_status, &gss_context, NULL);
418 return CURLE_COULDNT_CONNECT;
419 }
420
421 if(data->set.socks5_gssapi_nec) {
422 memcpy(socksreq, &gss_enc, 1);
423 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 1, &code);
424 if(code || ( 1 != nwritten)) {
425 failf(data, "Failed to send GSS-API encryption type.");
426 gss_delete_sec_context(&gss_status, &gss_context, NULL);
427 return CURLE_COULDNT_CONNECT;
428 }
429 }
430 else {
431 nwritten = Curl_conn_cf_send(cf->next, data,
432 (char *)gss_w_token.value,
433 gss_w_token.length, &code);
434 if(code || ((ssize_t)gss_w_token.length != nwritten)) {
435 failf(data, "Failed to send GSS-API encryption type.");
436 gss_release_buffer(&gss_status, &gss_w_token);
437 gss_delete_sec_context(&gss_status, &gss_context, NULL);
438 return CURLE_COULDNT_CONNECT;
439 }
440 gss_release_buffer(&gss_status, &gss_w_token);
441 }
442
443 result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread);
444 if(result || (actualread != 4)) {
445 failf(data, "Failed to receive GSS-API encryption response.");
446 gss_delete_sec_context(&gss_status, &gss_context, NULL);
447 return CURLE_COULDNT_CONNECT;
448 }
449
450 /* ignore the first (VER) byte */
451 if(socksreq[1] == 255) { /* status / message type */
452 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
453 socksreq[0], socksreq[1]);
454 gss_delete_sec_context(&gss_status, &gss_context, NULL);
455 return CURLE_COULDNT_CONNECT;
456 }
457
458 if(socksreq[1] != 2) { /* status / message type */
459 failf(data, "Invalid GSS-API encryption response type (%d %d).",
460 socksreq[0], socksreq[1]);
461 gss_delete_sec_context(&gss_status, &gss_context, NULL);
462 return CURLE_COULDNT_CONNECT;
463 }
464
465 memcpy(&us_length, socksreq + 2, sizeof(short));
466 us_length = ntohs(us_length);
467
468 gss_recv_token.length = us_length;
469 gss_recv_token.value = malloc(gss_recv_token.length);
470 if(!gss_recv_token.value) {
471 gss_delete_sec_context(&gss_status, &gss_context, NULL);
472 return CURLE_OUT_OF_MEMORY;
473 }
474 result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value,
475 gss_recv_token.length, &actualread);
476
477 if(result || (actualread != us_length)) {
478 failf(data, "Failed to receive GSS-API encryptrion type.");
479 gss_release_buffer(&gss_status, &gss_recv_token);
480 gss_delete_sec_context(&gss_status, &gss_context, NULL);
481 return CURLE_COULDNT_CONNECT;
482 }
483
484 if(!data->set.socks5_gssapi_nec) {
485 gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
486 &gss_recv_token, &gss_w_token,
487 0, GSS_C_QOP_DEFAULT);
488
489 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
490 gss_release_buffer(&gss_status, &gss_recv_token);
491 gss_release_buffer(&gss_status, &gss_w_token);
492 gss_delete_sec_context(&gss_status, &gss_context, NULL);
493 failf(data, "Failed to unwrap GSS-API encryption value into token.");
494 return CURLE_COULDNT_CONNECT;
495 }
496 gss_release_buffer(&gss_status, &gss_recv_token);
497
498 if(gss_w_token.length != 1) {
499 failf(data, "Invalid GSS-API encryption response length (%zu).",
500 gss_w_token.length);
501 gss_release_buffer(&gss_status, &gss_w_token);
502 gss_delete_sec_context(&gss_status, &gss_context, NULL);
503 return CURLE_COULDNT_CONNECT;
504 }
505
506 memcpy(socksreq, gss_w_token.value, gss_w_token.length);
507 gss_release_buffer(&gss_status, &gss_w_token);
508 }
509 else {
510 if(gss_recv_token.length != 1) {
511 failf(data, "Invalid GSS-API encryption response length (%zu).",
512 gss_recv_token.length);
513 gss_release_buffer(&gss_status, &gss_recv_token);
514 gss_delete_sec_context(&gss_status, &gss_context, NULL);
515 return CURLE_COULDNT_CONNECT;
516 }
517
518 memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
519 gss_release_buffer(&gss_status, &gss_recv_token);
520 }
521
522 (void)curlx_nonblock(sock, TRUE);
523
524 infof(data, "SOCKS5 access with%s protection granted.",
525 (socksreq[0] == 0)?"out GSS-API data":
526 ((socksreq[0] == 1)?" GSS-API integrity":" GSS-API confidentiality"));
527
528 conn->socks5_gssapi_enctype = socksreq[0];
529 if(socksreq[0] == 0)
530 gss_delete_sec_context(&gss_status, &gss_context, NULL);
531
532 return CURLE_OK;
533 }
534
535 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */
536