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 #if defined(__GNUC__) && defined(__APPLE__)
46 #pragma GCC diagnostic push
47 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
48 #endif
49
50 #define MAX_GSS_LEN 1024
51
52 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
53
54 /*
55 * Helper GSS-API error functions.
56 */
check_gss_err(struct Curl_easy * data,OM_uint32 major_status,OM_uint32 minor_status,const char * function)57 static int check_gss_err(struct Curl_easy *data,
58 OM_uint32 major_status,
59 OM_uint32 minor_status,
60 const char *function)
61 {
62 if(GSS_ERROR(major_status)) {
63 OM_uint32 maj_stat, min_stat;
64 OM_uint32 msg_ctx = 0;
65 gss_buffer_desc status_string = GSS_C_EMPTY_BUFFER;
66 struct dynbuf dbuf;
67
68 Curl_dyn_init(&dbuf, MAX_GSS_LEN);
69 msg_ctx = 0;
70 while(!msg_ctx) {
71 /* convert major status code (GSS-API error) to text */
72 maj_stat = gss_display_status(&min_stat, major_status,
73 GSS_C_GSS_CODE,
74 GSS_C_NULL_OID,
75 &msg_ctx, &status_string);
76 if(maj_stat == GSS_S_COMPLETE) {
77 if(Curl_dyn_addn(&dbuf, status_string.value,
78 status_string.length))
79 return 1; /* error */
80 gss_release_buffer(&min_stat, &status_string);
81 break;
82 }
83 gss_release_buffer(&min_stat, &status_string);
84 }
85 if(Curl_dyn_addn(&dbuf, ".\n", 2))
86 return 1; /* error */
87 msg_ctx = 0;
88 while(!msg_ctx) {
89 /* convert minor status code (underlying routine error) to text */
90 maj_stat = gss_display_status(&min_stat, minor_status,
91 GSS_C_MECH_CODE,
92 GSS_C_NULL_OID,
93 &msg_ctx, &status_string);
94 if(maj_stat == GSS_S_COMPLETE) {
95 if(Curl_dyn_addn(&dbuf, status_string.value,
96 status_string.length))
97 return 1; /* error */
98 gss_release_buffer(&min_stat, &status_string);
99 break;
100 }
101 gss_release_buffer(&min_stat, &status_string);
102 }
103 failf(data, "GSS-API error: %s failed: %s", function, Curl_dyn_ptr(&dbuf));
104 Curl_dyn_free(&dbuf);
105 return 1;
106 }
107
108 return 0;
109 }
110
Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter * cf,struct Curl_easy * data)111 CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
112 struct Curl_easy *data)
113 {
114 struct connectdata *conn = cf->conn;
115 curl_socket_t sock = conn->sock[cf->sockindex];
116 CURLcode code;
117 ssize_t actualread;
118 ssize_t nwritten;
119 int result;
120 OM_uint32 gss_major_status, gss_minor_status, gss_status;
121 OM_uint32 gss_ret_flags;
122 int gss_conf_state, gss_enc;
123 gss_buffer_desc service = GSS_C_EMPTY_BUFFER;
124 gss_buffer_desc gss_send_token = GSS_C_EMPTY_BUFFER;
125 gss_buffer_desc gss_recv_token = GSS_C_EMPTY_BUFFER;
126 gss_buffer_desc gss_w_token = GSS_C_EMPTY_BUFFER;
127 gss_buffer_desc *gss_token = GSS_C_NO_BUFFER;
128 gss_name_t server = GSS_C_NO_NAME;
129 gss_name_t gss_client_name = GSS_C_NO_NAME;
130 unsigned short us_length;
131 char *user = NULL;
132 unsigned char socksreq[4]; /* room for GSS-API exchange header only */
133 const char *serviceptr = data->set.str[STRING_PROXY_SERVICE_NAME] ?
134 data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd";
135 const size_t serviceptr_length = strlen(serviceptr);
136
137 /* GSS-API request looks like
138 * +----+------+-----+----------------+
139 * |VER | MTYP | LEN | TOKEN |
140 * +----+------+----------------------+
141 * | 1 | 1 | 2 | up to 2^16 - 1 |
142 * +----+------+-----+----------------+
143 */
144
145 /* prepare service name */
146 if(strchr(serviceptr, '/')) {
147 service.length = serviceptr_length;
148 service.value = Curl_memdup(serviceptr, service.length);
149 if(!service.value)
150 return CURLE_OUT_OF_MEMORY;
151
152 gss_major_status = gss_import_name(&gss_minor_status, &service,
153 (gss_OID) GSS_C_NULL_OID, &server);
154 }
155 else {
156 service.value = malloc(serviceptr_length +
157 strlen(conn->socks_proxy.host.name) + 2);
158 if(!service.value)
159 return CURLE_OUT_OF_MEMORY;
160 service.length = serviceptr_length +
161 strlen(conn->socks_proxy.host.name) + 1;
162 msnprintf(service.value, service.length + 1, "%s@%s",
163 serviceptr, conn->socks_proxy.host.name);
164
165 gss_major_status = gss_import_name(&gss_minor_status, &service,
166 GSS_C_NT_HOSTBASED_SERVICE, &server);
167 }
168
169 gss_release_buffer(&gss_status, &service); /* clear allocated memory */
170
171 if(check_gss_err(data, gss_major_status,
172 gss_minor_status, "gss_import_name()")) {
173 failf(data, "Failed to create service name.");
174 gss_release_name(&gss_status, &server);
175 return CURLE_COULDNT_CONNECT;
176 }
177
178 (void)curlx_nonblock(sock, FALSE);
179
180 /* As long as we need to keep sending some context info, and there is no */
181 /* errors, keep sending it... */
182 for(;;) {
183 gss_major_status = Curl_gss_init_sec_context(data,
184 &gss_minor_status,
185 &gss_context,
186 server,
187 &Curl_krb5_mech_oid,
188 NULL,
189 gss_token,
190 &gss_send_token,
191 TRUE,
192 &gss_ret_flags);
193
194 if(gss_token != GSS_C_NO_BUFFER)
195 gss_release_buffer(&gss_status, &gss_recv_token);
196 if(check_gss_err(data, gss_major_status,
197 gss_minor_status, "gss_init_sec_context")) {
198 gss_release_name(&gss_status, &server);
199 gss_release_buffer(&gss_status, &gss_recv_token);
200 gss_release_buffer(&gss_status, &gss_send_token);
201 gss_delete_sec_context(&gss_status, &gss_context, NULL);
202 failf(data, "Failed to initial GSS-API token.");
203 return CURLE_COULDNT_CONNECT;
204 }
205
206 if(gss_send_token.length) {
207 socksreq[0] = 1; /* GSS-API subnegotiation version */
208 socksreq[1] = 1; /* authentication message type */
209 us_length = htons((unsigned short)gss_send_token.length);
210 memcpy(socksreq + 2, &us_length, sizeof(short));
211
212 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4,
213 FALSE, &code);
214 if(code || (4 != nwritten)) {
215 failf(data, "Failed to send GSS-API authentication request.");
216 gss_release_name(&gss_status, &server);
217 gss_release_buffer(&gss_status, &gss_recv_token);
218 gss_release_buffer(&gss_status, &gss_send_token);
219 gss_delete_sec_context(&gss_status, &gss_context, NULL);
220 return CURLE_COULDNT_CONNECT;
221 }
222
223 nwritten = Curl_conn_cf_send(cf->next, data,
224 (char *)gss_send_token.value,
225 gss_send_token.length, FALSE, &code);
226 if(code || ((ssize_t)gss_send_token.length != nwritten)) {
227 failf(data, "Failed to send GSS-API authentication token.");
228 gss_release_name(&gss_status, &server);
229 gss_release_buffer(&gss_status, &gss_recv_token);
230 gss_release_buffer(&gss_status, &gss_send_token);
231 gss_delete_sec_context(&gss_status, &gss_context, NULL);
232 return CURLE_COULDNT_CONNECT;
233 }
234
235 }
236
237 gss_release_buffer(&gss_status, &gss_send_token);
238 gss_release_buffer(&gss_status, &gss_recv_token);
239 if(gss_major_status != GSS_S_CONTINUE_NEEDED)
240 break;
241
242 /* analyse response */
243
244 /* GSS-API response looks like
245 * +----+------+-----+----------------+
246 * |VER | MTYP | LEN | TOKEN |
247 * +----+------+----------------------+
248 * | 1 | 1 | 2 | up to 2^16 - 1 |
249 * +----+------+-----+----------------+
250 */
251
252 result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread);
253 if(result || (actualread != 4)) {
254 failf(data, "Failed to receive GSS-API authentication response.");
255 gss_release_name(&gss_status, &server);
256 gss_delete_sec_context(&gss_status, &gss_context, NULL);
257 return CURLE_COULDNT_CONNECT;
258 }
259
260 /* ignore the first (VER) byte */
261 if(socksreq[1] == 255) { /* status / message type */
262 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
263 socksreq[0], socksreq[1]);
264 gss_release_name(&gss_status, &server);
265 gss_delete_sec_context(&gss_status, &gss_context, NULL);
266 return CURLE_COULDNT_CONNECT;
267 }
268
269 if(socksreq[1] != 1) { /* status / message type */
270 failf(data, "Invalid GSS-API authentication response type (%d %d).",
271 socksreq[0], socksreq[1]);
272 gss_release_name(&gss_status, &server);
273 gss_delete_sec_context(&gss_status, &gss_context, NULL);
274 return CURLE_COULDNT_CONNECT;
275 }
276
277 memcpy(&us_length, socksreq + 2, sizeof(short));
278 us_length = ntohs(us_length);
279
280 gss_recv_token.length = us_length;
281 gss_recv_token.value = malloc(us_length);
282 if(!gss_recv_token.value) {
283 failf(data,
284 "Could not allocate memory for GSS-API authentication "
285 "response token.");
286 gss_release_name(&gss_status, &server);
287 gss_delete_sec_context(&gss_status, &gss_context, NULL);
288 return CURLE_OUT_OF_MEMORY;
289 }
290
291 result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value,
292 gss_recv_token.length, &actualread);
293
294 if(result || (actualread != us_length)) {
295 failf(data, "Failed to receive GSS-API authentication token.");
296 gss_release_name(&gss_status, &server);
297 gss_release_buffer(&gss_status, &gss_recv_token);
298 gss_delete_sec_context(&gss_status, &gss_context, NULL);
299 return CURLE_COULDNT_CONNECT;
300 }
301
302 gss_token = &gss_recv_token;
303 }
304
305 gss_release_name(&gss_status, &server);
306
307 /* Everything is good so far, user was authenticated! */
308 gss_major_status = gss_inquire_context(&gss_minor_status, gss_context,
309 &gss_client_name, NULL, NULL, NULL,
310 NULL, NULL, NULL);
311 if(check_gss_err(data, gss_major_status,
312 gss_minor_status, "gss_inquire_context")) {
313 gss_delete_sec_context(&gss_status, &gss_context, NULL);
314 gss_release_name(&gss_status, &gss_client_name);
315 failf(data, "Failed to determine username.");
316 return CURLE_COULDNT_CONNECT;
317 }
318 gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
319 &gss_send_token, NULL);
320 if(check_gss_err(data, gss_major_status,
321 gss_minor_status, "gss_display_name")) {
322 gss_delete_sec_context(&gss_status, &gss_context, NULL);
323 gss_release_name(&gss_status, &gss_client_name);
324 gss_release_buffer(&gss_status, &gss_send_token);
325 failf(data, "Failed to determine username.");
326 return CURLE_COULDNT_CONNECT;
327 }
328 user = malloc(gss_send_token.length + 1);
329 if(!user) {
330 gss_delete_sec_context(&gss_status, &gss_context, NULL);
331 gss_release_name(&gss_status, &gss_client_name);
332 gss_release_buffer(&gss_status, &gss_send_token);
333 return CURLE_OUT_OF_MEMORY;
334 }
335
336 memcpy(user, gss_send_token.value, gss_send_token.length);
337 user[gss_send_token.length] = '\0';
338 gss_release_name(&gss_status, &gss_client_name);
339 gss_release_buffer(&gss_status, &gss_send_token);
340 infof(data, "SOCKS5 server authenticated user %s with GSS-API.",user);
341 free(user);
342 user = NULL;
343
344 /* Do encryption */
345 socksreq[0] = 1; /* GSS-API subnegotiation version */
346 socksreq[1] = 2; /* encryption message type */
347
348 gss_enc = 0; /* no data protection */
349 /* do confidentiality protection if supported */
350 if(gss_ret_flags & GSS_C_CONF_FLAG)
351 gss_enc = 2;
352 /* else do integrity protection */
353 else if(gss_ret_flags & GSS_C_INTEG_FLAG)
354 gss_enc = 1;
355
356 infof(data, "SOCKS5 server supports GSS-API %s data protection.",
357 (gss_enc == 0) ? "no" :
358 ((gss_enc == 1) ? "integrity" : "confidentiality"));
359 /* force for the moment to no data protection */
360 gss_enc = 0;
361 /*
362 * Sending the encryption type in clear seems wrong. It should be
363 * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
364 * The NEC reference implementations on which this is based is
365 * therefore at fault
366 *
367 * +------+------+------+.......................+
368 * + ver | mtyp | len | token |
369 * +------+------+------+.......................+
370 * + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
371 * +------+------+------+.......................+
372 *
373 * Where:
374 *
375 * - "ver" is the protocol version number, here 1 to represent the
376 * first version of the SOCKS/GSS-API protocol
377 *
378 * - "mtyp" is the message type, here 2 to represent a protection
379 * -level negotiation message
380 *
381 * - "len" is the length of the "token" field in octets
382 *
383 * - "token" is the GSS-API encapsulated protection level
384 *
385 * The token is produced by encapsulating an octet containing the
386 * required protection level using gss_seal()/gss_wrap() with conf_req
387 * set to FALSE. The token is verified using gss_unseal()/
388 * gss_unwrap().
389 *
390 */
391 if(data->set.socks5_gssapi_nec) {
392 us_length = htons((short)1);
393 memcpy(socksreq + 2, &us_length, sizeof(short));
394 }
395 else {
396 gss_send_token.length = 1;
397 gss_send_token.value = Curl_memdup(&gss_enc, 1);
398 if(!gss_send_token.value) {
399 gss_delete_sec_context(&gss_status, &gss_context, NULL);
400 return CURLE_OUT_OF_MEMORY;
401 }
402
403 gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
404 GSS_C_QOP_DEFAULT, &gss_send_token,
405 &gss_conf_state, &gss_w_token);
406
407 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
408 gss_release_buffer(&gss_status, &gss_send_token);
409 gss_release_buffer(&gss_status, &gss_w_token);
410 gss_delete_sec_context(&gss_status, &gss_context, NULL);
411 failf(data, "Failed to wrap GSS-API encryption value into token.");
412 return CURLE_COULDNT_CONNECT;
413 }
414 gss_release_buffer(&gss_status, &gss_send_token);
415
416 us_length = htons((unsigned short)gss_w_token.length);
417 memcpy(socksreq + 2, &us_length, sizeof(short));
418 }
419
420 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, FALSE,
421 &code);
422 if(code || (4 != nwritten)) {
423 failf(data, "Failed to send GSS-API encryption request.");
424 gss_release_buffer(&gss_status, &gss_w_token);
425 gss_delete_sec_context(&gss_status, &gss_context, NULL);
426 return CURLE_COULDNT_CONNECT;
427 }
428
429 if(data->set.socks5_gssapi_nec) {
430 memcpy(socksreq, &gss_enc, 1);
431 nwritten = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 1, FALSE,
432 &code);
433 if(code || ( 1 != nwritten)) {
434 failf(data, "Failed to send GSS-API encryption type.");
435 gss_delete_sec_context(&gss_status, &gss_context, NULL);
436 return CURLE_COULDNT_CONNECT;
437 }
438 }
439 else {
440 nwritten = Curl_conn_cf_send(cf->next, data,
441 (char *)gss_w_token.value,
442 gss_w_token.length, FALSE, &code);
443 if(code || ((ssize_t)gss_w_token.length != nwritten)) {
444 failf(data, "Failed to send GSS-API encryption type.");
445 gss_release_buffer(&gss_status, &gss_w_token);
446 gss_delete_sec_context(&gss_status, &gss_context, NULL);
447 return CURLE_COULDNT_CONNECT;
448 }
449 gss_release_buffer(&gss_status, &gss_w_token);
450 }
451
452 result = Curl_blockread_all(cf, data, (char *)socksreq, 4, &actualread);
453 if(result || (actualread != 4)) {
454 failf(data, "Failed to receive GSS-API encryption response.");
455 gss_delete_sec_context(&gss_status, &gss_context, NULL);
456 return CURLE_COULDNT_CONNECT;
457 }
458
459 /* ignore the first (VER) byte */
460 if(socksreq[1] == 255) { /* status / message type */
461 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
462 socksreq[0], socksreq[1]);
463 gss_delete_sec_context(&gss_status, &gss_context, NULL);
464 return CURLE_COULDNT_CONNECT;
465 }
466
467 if(socksreq[1] != 2) { /* status / message type */
468 failf(data, "Invalid GSS-API encryption response type (%d %d).",
469 socksreq[0], socksreq[1]);
470 gss_delete_sec_context(&gss_status, &gss_context, NULL);
471 return CURLE_COULDNT_CONNECT;
472 }
473
474 memcpy(&us_length, socksreq + 2, sizeof(short));
475 us_length = ntohs(us_length);
476
477 gss_recv_token.length = us_length;
478 gss_recv_token.value = malloc(gss_recv_token.length);
479 if(!gss_recv_token.value) {
480 gss_delete_sec_context(&gss_status, &gss_context, NULL);
481 return CURLE_OUT_OF_MEMORY;
482 }
483 result = Curl_blockread_all(cf, data, (char *)gss_recv_token.value,
484 gss_recv_token.length, &actualread);
485
486 if(result || (actualread != us_length)) {
487 failf(data, "Failed to receive GSS-API encryption type.");
488 gss_release_buffer(&gss_status, &gss_recv_token);
489 gss_delete_sec_context(&gss_status, &gss_context, NULL);
490 return CURLE_COULDNT_CONNECT;
491 }
492
493 if(!data->set.socks5_gssapi_nec) {
494 gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
495 &gss_recv_token, &gss_w_token,
496 0, GSS_C_QOP_DEFAULT);
497
498 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
499 gss_release_buffer(&gss_status, &gss_recv_token);
500 gss_release_buffer(&gss_status, &gss_w_token);
501 gss_delete_sec_context(&gss_status, &gss_context, NULL);
502 failf(data, "Failed to unwrap GSS-API encryption value into token.");
503 return CURLE_COULDNT_CONNECT;
504 }
505 gss_release_buffer(&gss_status, &gss_recv_token);
506
507 if(gss_w_token.length != 1) {
508 failf(data, "Invalid GSS-API encryption response length (%zu).",
509 gss_w_token.length);
510 gss_release_buffer(&gss_status, &gss_w_token);
511 gss_delete_sec_context(&gss_status, &gss_context, NULL);
512 return CURLE_COULDNT_CONNECT;
513 }
514
515 memcpy(socksreq, gss_w_token.value, gss_w_token.length);
516 gss_release_buffer(&gss_status, &gss_w_token);
517 }
518 else {
519 if(gss_recv_token.length != 1) {
520 failf(data, "Invalid GSS-API encryption response length (%zu).",
521 gss_recv_token.length);
522 gss_release_buffer(&gss_status, &gss_recv_token);
523 gss_delete_sec_context(&gss_status, &gss_context, NULL);
524 return CURLE_COULDNT_CONNECT;
525 }
526
527 memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
528 gss_release_buffer(&gss_status, &gss_recv_token);
529 }
530
531 (void)curlx_nonblock(sock, TRUE);
532
533 infof(data, "SOCKS5 access with%s protection granted.",
534 (socksreq[0] == 0) ? "out GSS-API data":
535 ((socksreq[0] == 1) ? " GSS-API integrity" :
536 " GSS-API confidentiality"));
537
538 conn->socks5_gssapi_enctype = socksreq[0];
539 if(socksreq[0] == 0)
540 gss_delete_sec_context(&gss_status, &gss_context, NULL);
541
542 return CURLE_OK;
543 }
544
545 #if defined(__GNUC__) && defined(__APPLE__)
546 #pragma GCC diagnostic pop
547 #endif
548
549 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */
550