1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2009, Markus Moeller, <markus_moeller@compuserve.com>
9 * Copyright (C) 2012 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
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.haxx.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 ***************************************************************************/
23
24#include "curl_setup.h"
25
26#if defined(HAVE_GSSAPI) && !defined(CURL_DISABLE_PROXY)
27
28#include "curl_gssapi.h"
29#include "urldata.h"
30#include "sendf.h"
31#include "connect.h"
32#include "timeval.h"
33#include "socks.h"
34#include "warnless.h"
35
36/* The last 3 #include files should be in this order */
37#include "curl_printf.h"
38#include "curl_memory.h"
39#include "memdebug.h"
40
41static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
42
43/*
44 * Helper GSS-API error functions.
45 */
46static int check_gss_err(struct Curl_easy *data,
47 OM_uint32 major_status,
48 OM_uint32 minor_status,
49 const char *function)
50{
51 if(GSS_ERROR(major_status)) {
52 OM_uint32 maj_stat, min_stat;
53 OM_uint32 msg_ctx = 0;
54 gss_buffer_desc status_string;
55 char buf[1024];
56 size_t len;
57
58 len = 0;
59 msg_ctx = 0;
60 while(!msg_ctx) {
61 /* convert major status code (GSS-API error) to text */
62 maj_stat = gss_display_status(&min_stat, major_status,
63 GSS_C_GSS_CODE,
64 GSS_C_NULL_OID,
65 &msg_ctx, &status_string);
66 if(maj_stat == GSS_S_COMPLETE) {
67 if(sizeof(buf) > len + status_string.length + 1) {
68 strcpy(buf + len, (char *) status_string.value);
69 len += status_string.length;
70 }
71 gss_release_buffer(&min_stat, &status_string);
72 break;
73 }
74 gss_release_buffer(&min_stat, &status_string);
75 }
76 if(sizeof(buf) > len + 3) {
77 strcpy(buf + len, ".\n");
78 len += 2;
79 }
80 msg_ctx = 0;
81 while(!msg_ctx) {
82 /* convert minor status code (underlying routine error) to text */
83 maj_stat = gss_display_status(&min_stat, minor_status,
84 GSS_C_MECH_CODE,
85 GSS_C_NULL_OID,
86 &msg_ctx, &status_string);
87 if(maj_stat == GSS_S_COMPLETE) {
88 if(sizeof(buf) > len + status_string.length)
89 strcpy(buf + len, (char *) status_string.value);
90 gss_release_buffer(&min_stat, &status_string);
91 break;
92 }
93 gss_release_buffer(&min_stat, &status_string);
94 }
95 failf(data, "GSS-API error: %s failed:\n%s", function, buf);
96 return 1;
97 }
98
99 return 0;
100}
101
102CURLcode Curl_SOCKS5_gssapi_negotiate(int sockindex,
103 struct connectdata *conn)
104{
105 struct Curl_easy *data = conn->data;
106 curl_socket_t sock = conn->sock[sockindex];
107 CURLcode code;
108 ssize_t actualread;
109 ssize_t written;
110 int result;
111 OM_uint32 gss_major_status, gss_minor_status, gss_status;
112 OM_uint32 gss_ret_flags;
113 int gss_conf_state, gss_enc;
114 gss_buffer_desc service = GSS_C_EMPTY_BUFFER;
115 gss_buffer_desc gss_send_token = GSS_C_EMPTY_BUFFER;
116 gss_buffer_desc gss_recv_token = GSS_C_EMPTY_BUFFER;
117 gss_buffer_desc gss_w_token = GSS_C_EMPTY_BUFFER;
118 gss_buffer_desc* gss_token = GSS_C_NO_BUFFER;
119 gss_name_t server = GSS_C_NO_NAME;
120 gss_name_t gss_client_name = GSS_C_NO_NAME;
121 unsigned short us_length;
122 char *user = NULL;
123 unsigned char socksreq[4]; /* room for GSS-API exchange header only */
124 const char *serviceptr = data->set.str[STRING_PROXY_SERVICE_NAME] ?
125 data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd";
126 const size_t serviceptr_length = strlen(serviceptr);
127
128 /* GSS-API request looks like
129 * +----+------+-----+----------------+
130 * |VER | MTYP | LEN | TOKEN |
131 * +----+------+----------------------+
132 * | 1 | 1 | 2 | up to 2^16 - 1 |
133 * +----+------+-----+----------------+
134 */
135
136 /* prepare service name */
137 if(strchr(serviceptr, '/')) {
138 service.length = serviceptr_length;
139 service.value = malloc(service.length);
140 if(!service.value)
141 return CURLE_OUT_OF_MEMORY;
142 memcpy(service.value, serviceptr, service.length);
143
144 gss_major_status = gss_import_name(&gss_minor_status, &service,
145 (gss_OID) GSS_C_NULL_OID, &server);
146 }
147 else {
148 service.value = malloc(serviceptr_length +
149 strlen(conn->socks_proxy.host.name) + 2);
150 if(!service.value)
151 return CURLE_OUT_OF_MEMORY;
152 service.length = serviceptr_length +
153 strlen(conn->socks_proxy.host.name) + 1;
154 msnprintf(service.value, service.length + 1, "%s@%s",
155 serviceptr, conn->socks_proxy.host.name);
156
157 gss_major_status = gss_import_name(&gss_minor_status, &service,
158 GSS_C_NT_HOSTBASED_SERVICE, &server);
159 }
160
161 gss_release_buffer(&gss_status, &service); /* clear allocated memory */
162
163 if(check_gss_err(data, gss_major_status,
164 gss_minor_status, "gss_import_name()")) {
165 failf(data, "Failed to create service name.");
166 gss_release_name(&gss_status, &server);
167 return CURLE_COULDNT_CONNECT;
168 }
169
170 /* As long as we need to keep sending some context info, and there's no */
171 /* errors, keep sending it... */
172 for(;;) {
173 gss_major_status = Curl_gss_init_sec_context(data,
174 &gss_minor_status,
175 &gss_context,
176 server,
177 &Curl_krb5_mech_oid,
178 NULL,
179 gss_token,
180 &gss_send_token,
181 TRUE,
182 &gss_ret_flags);
183
184 if(gss_token != GSS_C_NO_BUFFER)
185 gss_release_buffer(&gss_status, &gss_recv_token);
186 if(check_gss_err(data, gss_major_status,
187 gss_minor_status, "gss_init_sec_context")) {
188 gss_release_name(&gss_status, &server);
189 gss_release_buffer(&gss_status, &gss_recv_token);
190 gss_release_buffer(&gss_status, &gss_send_token);
191 gss_delete_sec_context(&gss_status, &gss_context, NULL);
192 failf(data, "Failed to initial GSS-API token.");
193 return CURLE_COULDNT_CONNECT;
194 }
195
196 if(gss_send_token.length != 0) {
197 socksreq[0] = 1; /* GSS-API subnegotiation version */
198 socksreq[1] = 1; /* authentication message type */
199 us_length = htons((short)gss_send_token.length);
200 memcpy(socksreq + 2, &us_length, sizeof(short));
201
202 code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
203 if(code || (4 != written)) {
204 failf(data, "Failed to send GSS-API authentication request.");
205 gss_release_name(&gss_status, &server);
206 gss_release_buffer(&gss_status, &gss_recv_token);
207 gss_release_buffer(&gss_status, &gss_send_token);
208 gss_delete_sec_context(&gss_status, &gss_context, NULL);
209 return CURLE_COULDNT_CONNECT;
210 }
211
212 code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
213 gss_send_token.length, &written);
214
215 if(code || ((ssize_t)gss_send_token.length != written)) {
216 failf(data, "Failed to send GSS-API authentication token.");
217 gss_release_name(&gss_status, &server);
218 gss_release_buffer(&gss_status, &gss_recv_token);
219 gss_release_buffer(&gss_status, &gss_send_token);
220 gss_delete_sec_context(&gss_status, &gss_context, NULL);
221 return CURLE_COULDNT_CONNECT;
222 }
223
224 }
225
226 gss_release_buffer(&gss_status, &gss_send_token);
227 gss_release_buffer(&gss_status, &gss_recv_token);
228 if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
229
230 /* analyse response */
231
232 /* GSS-API response looks like
233 * +----+------+-----+----------------+
234 * |VER | MTYP | LEN | TOKEN |
235 * +----+------+----------------------+
236 * | 1 | 1 | 2 | up to 2^16 - 1 |
237 * +----+------+-----+----------------+
238 */
239
240 result = Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
241 if(result || (actualread != 4)) {
242 failf(data, "Failed to receive GSS-API authentication response.");
243 gss_release_name(&gss_status, &server);
244 gss_delete_sec_context(&gss_status, &gss_context, NULL);
245 return CURLE_COULDNT_CONNECT;
246 }
247
248 /* ignore the first (VER) byte */
249 if(socksreq[1] == 255) { /* status / message type */
250 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
251 socksreq[0], socksreq[1]);
252 gss_release_name(&gss_status, &server);
253 gss_delete_sec_context(&gss_status, &gss_context, NULL);
254 return CURLE_COULDNT_CONNECT;
255 }
256
257 if(socksreq[1] != 1) { /* status / messgae type */
258 failf(data, "Invalid GSS-API authentication response type (%d %d).",
259 socksreq[0], socksreq[1]);
260 gss_release_name(&gss_status, &server);
261 gss_delete_sec_context(&gss_status, &gss_context, NULL);
262 return CURLE_COULDNT_CONNECT;
263 }
264
265 memcpy(&us_length, socksreq + 2, sizeof(short));
266 us_length = ntohs(us_length);
267
268 gss_recv_token.length = us_length;
269 gss_recv_token.value = malloc(us_length);
270 if(!gss_recv_token.value) {
271 failf(data,
272 "Could not allocate memory for GSS-API authentication "
273 "response token.");
274 gss_release_name(&gss_status, &server);
275 gss_delete_sec_context(&gss_status, &gss_context, NULL);
276 return CURLE_OUT_OF_MEMORY;
277 }
278
279 result = Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
280 gss_recv_token.length, &actualread);
281
282 if(result || (actualread != us_length)) {
283 failf(data, "Failed to receive GSS-API authentication token.");
284 gss_release_name(&gss_status, &server);
285 gss_release_buffer(&gss_status, &gss_recv_token);
286 gss_delete_sec_context(&gss_status, &gss_context, NULL);
287 return CURLE_COULDNT_CONNECT;
288 }
289
290 gss_token = &gss_recv_token;
291 }
292
293 gss_release_name(&gss_status, &server);
294
295 /* Everything is good so far, user was authenticated! */
296 gss_major_status = gss_inquire_context(&gss_minor_status, gss_context,
297 &gss_client_name, NULL, NULL, NULL,
298 NULL, NULL, NULL);
299 if(check_gss_err(data, gss_major_status,
300 gss_minor_status, "gss_inquire_context")) {
301 gss_delete_sec_context(&gss_status, &gss_context, NULL);
302 gss_release_name(&gss_status, &gss_client_name);
303 failf(data, "Failed to determine user name.");
304 return CURLE_COULDNT_CONNECT;
305 }
306 gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
307 &gss_send_token, NULL);
308 if(check_gss_err(data, gss_major_status,
309 gss_minor_status, "gss_display_name")) {
310 gss_delete_sec_context(&gss_status, &gss_context, NULL);
311 gss_release_name(&gss_status, &gss_client_name);
312 gss_release_buffer(&gss_status, &gss_send_token);
313 failf(data, "Failed to determine user name.");
314 return CURLE_COULDNT_CONNECT;
315 }
316 user = malloc(gss_send_token.length + 1);
317 if(!user) {
318 gss_delete_sec_context(&gss_status, &gss_context, NULL);
319 gss_release_name(&gss_status, &gss_client_name);
320 gss_release_buffer(&gss_status, &gss_send_token);
321 return CURLE_OUT_OF_MEMORY;
322 }
323
324 memcpy(user, gss_send_token.value, gss_send_token.length);
325 user[gss_send_token.length] = '\0';
326 gss_release_name(&gss_status, &gss_client_name);
327 gss_release_buffer(&gss_status, &gss_send_token);
328 infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
329 free(user);
330 user = NULL;
331
332 /* Do encryption */
333 socksreq[0] = 1; /* GSS-API subnegotiation version */
334 socksreq[1] = 2; /* encryption message type */
335
336 gss_enc = 0; /* no data protection */
337 /* do confidentiality protection if supported */
338 if(gss_ret_flags & GSS_C_CONF_FLAG)
339 gss_enc = 2;
340 /* else do integrity protection */
341 else if(gss_ret_flags & GSS_C_INTEG_FLAG)
342 gss_enc = 1;
343
344 infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
345 (gss_enc == 0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
346 /* force for the moment to no data protection */
347 gss_enc = 0;
348 /*
349 * Sending the encryption type in clear seems wrong. It should be
350 * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
351 * The NEC reference implementations on which this is based is
352 * therefore at fault
353 *
354 * +------+------+------+.......................+
355 * + ver | mtyp | len | token |
356 * +------+------+------+.......................+
357 * + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
358 * +------+------+------+.......................+
359 *
360 * Where:
361 *
362 * - "ver" is the protocol version number, here 1 to represent the
363 * first version of the SOCKS/GSS-API protocol
364 *
365 * - "mtyp" is the message type, here 2 to represent a protection
366 * -level negotiation message
367 *
368 * - "len" is the length of the "token" field in octets
369 *
370 * - "token" is the GSS-API encapsulated protection level
371 *
372 * The token is produced by encapsulating an octet containing the
373 * required protection level using gss_seal()/gss_wrap() with conf_req
374 * set to FALSE. The token is verified using gss_unseal()/
375 * gss_unwrap().
376 *
377 */
378 if(data->set.socks5_gssapi_nec) {
379 us_length = htons((short)1);
380 memcpy(socksreq + 2, &us_length, sizeof(short));
381 }
382 else {
383 gss_send_token.length = 1;
384 gss_send_token.value = malloc(1);
385 if(!gss_send_token.value) {
386 gss_delete_sec_context(&gss_status, &gss_context, NULL);
387 return CURLE_OUT_OF_MEMORY;
388 }
389 memcpy(gss_send_token.value, &gss_enc, 1);
390
391 gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
392 GSS_C_QOP_DEFAULT, &gss_send_token,
393 &gss_conf_state, &gss_w_token);
394
395 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
396 gss_release_buffer(&gss_status, &gss_send_token);
397 gss_release_buffer(&gss_status, &gss_w_token);
398 gss_delete_sec_context(&gss_status, &gss_context, NULL);
399 failf(data, "Failed to wrap GSS-API encryption value into token.");
400 return CURLE_COULDNT_CONNECT;
401 }
402 gss_release_buffer(&gss_status, &gss_send_token);
403
404 us_length = htons((short)gss_w_token.length);
405 memcpy(socksreq + 2, &us_length, sizeof(short));
406 }
407
408 code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
409 if(code || (4 != written)) {
410 failf(data, "Failed to send GSS-API encryption request.");
411 gss_release_buffer(&gss_status, &gss_w_token);
412 gss_delete_sec_context(&gss_status, &gss_context, NULL);
413 return CURLE_COULDNT_CONNECT;
414 }
415
416 if(data->set.socks5_gssapi_nec) {
417 memcpy(socksreq, &gss_enc, 1);
418 code = Curl_write_plain(conn, sock, socksreq, 1, &written);
419 if(code || ( 1 != written)) {
420 failf(data, "Failed to send GSS-API encryption type.");
421 gss_delete_sec_context(&gss_status, &gss_context, NULL);
422 return CURLE_COULDNT_CONNECT;
423 }
424 }
425 else {
426 code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
427 gss_w_token.length, &written);
428 if(code || ((ssize_t)gss_w_token.length != written)) {
429 failf(data, "Failed to send GSS-API encryption type.");
430 gss_release_buffer(&gss_status, &gss_w_token);
431 gss_delete_sec_context(&gss_status, &gss_context, NULL);
432 return CURLE_COULDNT_CONNECT;
433 }
434 gss_release_buffer(&gss_status, &gss_w_token);
435 }
436
437 result = Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
438 if(result || (actualread != 4)) {
439 failf(data, "Failed to receive GSS-API encryption response.");
440 gss_delete_sec_context(&gss_status, &gss_context, NULL);
441 return CURLE_COULDNT_CONNECT;
442 }
443
444 /* ignore the first (VER) byte */
445 if(socksreq[1] == 255) { /* status / message type */
446 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
447 socksreq[0], socksreq[1]);
448 gss_delete_sec_context(&gss_status, &gss_context, NULL);
449 return CURLE_COULDNT_CONNECT;
450 }
451
452 if(socksreq[1] != 2) { /* status / messgae type */
453 failf(data, "Invalid GSS-API encryption response type (%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 memcpy(&us_length, socksreq + 2, sizeof(short));
460 us_length = ntohs(us_length);
461
462 gss_recv_token.length = us_length;
463 gss_recv_token.value = malloc(gss_recv_token.length);
464 if(!gss_recv_token.value) {
465 gss_delete_sec_context(&gss_status, &gss_context, NULL);
466 return CURLE_OUT_OF_MEMORY;
467 }
468 result = Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
469 gss_recv_token.length, &actualread);
470
471 if(result || (actualread != us_length)) {
472 failf(data, "Failed to receive GSS-API encryptrion type.");
473 gss_release_buffer(&gss_status, &gss_recv_token);
474 gss_delete_sec_context(&gss_status, &gss_context, NULL);
475 return CURLE_COULDNT_CONNECT;
476 }
477
478 if(!data->set.socks5_gssapi_nec) {
479 gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
480 &gss_recv_token, &gss_w_token,
481 0, GSS_C_QOP_DEFAULT);
482
483 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
484 gss_release_buffer(&gss_status, &gss_recv_token);
485 gss_release_buffer(&gss_status, &gss_w_token);
486 gss_delete_sec_context(&gss_status, &gss_context, NULL);
487 failf(data, "Failed to unwrap GSS-API encryption value into token.");
488 return CURLE_COULDNT_CONNECT;
489 }
490 gss_release_buffer(&gss_status, &gss_recv_token);
491
492 if(gss_w_token.length != 1) {
493 failf(data, "Invalid GSS-API encryption response length (%d).",
494 gss_w_token.length);
495 gss_release_buffer(&gss_status, &gss_w_token);
496 gss_delete_sec_context(&gss_status, &gss_context, NULL);
497 return CURLE_COULDNT_CONNECT;
498 }
499
500 memcpy(socksreq, gss_w_token.value, gss_w_token.length);
501 gss_release_buffer(&gss_status, &gss_w_token);
502 }
503 else {
504 if(gss_recv_token.length != 1) {
505 failf(data, "Invalid GSS-API encryption response length (%d).",
506 gss_recv_token.length);
507 gss_release_buffer(&gss_status, &gss_recv_token);
508 gss_delete_sec_context(&gss_status, &gss_context, NULL);
509 return CURLE_COULDNT_CONNECT;
510 }
511
512 memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
513 gss_release_buffer(&gss_status, &gss_recv_token);
514 }
515
516 infof(data, "SOCKS5 access with%s protection granted.\n",
517 (socksreq[0] == 0)?"out GSS-API data":
518 ((socksreq[0] == 1)?" GSS-API integrity":" GSS-API confidentiality"));
519
520 conn->socks5_gssapi_enctype = socksreq[0];
521 if(socksreq[0] == 0)
522 gss_delete_sec_context(&gss_status, &gss_context, NULL);
523
524 return CURLE_OK;
525}
526
527#endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */
528