1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2009, 2011, Markus Moeller, <markus_moeller@compuserve.com>
9 * Copyright (C) 2012 - 2016, 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
41 static gss_ctx_id_t gss_context = GSS_C_NO_CONTEXT;
42
43 /*
44 * Helper GSS-API error functions.
45 */
check_gss_err(struct Curl_easy * data,OM_uint32 major_status,OM_uint32 minor_status,const char * function)46 static 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
Curl_SOCKS5_gssapi_negotiate(int sockindex,struct connectdata * conn)102 CURLcode 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
127 /* GSS-API request looks like
128 * +----+------+-----+----------------+
129 * |VER | MTYP | LEN | TOKEN |
130 * +----+------+----------------------+
131 * | 1 | 1 | 2 | up to 2^16 - 1 |
132 * +----+------+-----+----------------+
133 */
134
135 /* prepare service name */
136 if(strchr(serviceptr, '/')) {
137 service.value = malloc(strlen(serviceptr));
138 if(!service.value)
139 return CURLE_OUT_OF_MEMORY;
140 service.length = strlen(serviceptr);
141 memcpy(service.value, serviceptr, service.length);
142
143 gss_major_status = gss_import_name(&gss_minor_status, &service,
144 (gss_OID) GSS_C_NULL_OID, &server);
145 }
146 else {
147 service.value = malloc(strlen(serviceptr) +strlen(conn->proxy.name)+2);
148 if(!service.value)
149 return CURLE_OUT_OF_MEMORY;
150 service.length = strlen(serviceptr) +strlen(conn->proxy.name)+1;
151 snprintf(service.value, service.length+1, "%s@%s",
152 serviceptr, conn->proxy.name);
153
154 gss_major_status = gss_import_name(&gss_minor_status, &service,
155 GSS_C_NT_HOSTBASED_SERVICE, &server);
156 }
157
158 gss_release_buffer(&gss_status, &service); /* clear allocated memory */
159
160 if(check_gss_err(data, gss_major_status,
161 gss_minor_status, "gss_import_name()")) {
162 failf(data, "Failed to create service name.");
163 gss_release_name(&gss_status, &server);
164 return CURLE_COULDNT_CONNECT;
165 }
166
167 /* As long as we need to keep sending some context info, and there's no */
168 /* errors, keep sending it... */
169 for(;;) {
170 gss_major_status = Curl_gss_init_sec_context(data,
171 &gss_minor_status,
172 &gss_context,
173 server,
174 &Curl_krb5_mech_oid,
175 NULL,
176 gss_token,
177 &gss_send_token,
178 TRUE,
179 &gss_ret_flags);
180
181 if(gss_token != GSS_C_NO_BUFFER)
182 gss_release_buffer(&gss_status, &gss_recv_token);
183 if(check_gss_err(data, gss_major_status,
184 gss_minor_status, "gss_init_sec_context")) {
185 gss_release_name(&gss_status, &server);
186 gss_release_buffer(&gss_status, &gss_recv_token);
187 gss_release_buffer(&gss_status, &gss_send_token);
188 gss_delete_sec_context(&gss_status, &gss_context, NULL);
189 failf(data, "Failed to initial GSS-API token.");
190 return CURLE_COULDNT_CONNECT;
191 }
192
193 if(gss_send_token.length != 0) {
194 socksreq[0] = 1; /* GSS-API subnegotiation version */
195 socksreq[1] = 1; /* authentication message type */
196 us_length = htons((short)gss_send_token.length);
197 memcpy(socksreq+2, &us_length, sizeof(short));
198
199 code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
200 if(code || (4 != written)) {
201 failf(data, "Failed to send GSS-API authentication request.");
202 gss_release_name(&gss_status, &server);
203 gss_release_buffer(&gss_status, &gss_recv_token);
204 gss_release_buffer(&gss_status, &gss_send_token);
205 gss_delete_sec_context(&gss_status, &gss_context, NULL);
206 return CURLE_COULDNT_CONNECT;
207 }
208
209 code = Curl_write_plain(conn, sock, (char *)gss_send_token.value,
210 gss_send_token.length, &written);
211
212 if(code || ((ssize_t)gss_send_token.length != written)) {
213 failf(data, "Failed to send GSS-API authentication token.");
214 gss_release_name(&gss_status, &server);
215 gss_release_buffer(&gss_status, &gss_recv_token);
216 gss_release_buffer(&gss_status, &gss_send_token);
217 gss_delete_sec_context(&gss_status, &gss_context, NULL);
218 return CURLE_COULDNT_CONNECT;
219 }
220
221 }
222
223 gss_release_buffer(&gss_status, &gss_send_token);
224 gss_release_buffer(&gss_status, &gss_recv_token);
225 if(gss_major_status != GSS_S_CONTINUE_NEEDED) break;
226
227 /* analyse response */
228
229 /* GSS-API response looks like
230 * +----+------+-----+----------------+
231 * |VER | MTYP | LEN | TOKEN |
232 * +----+------+----------------------+
233 * | 1 | 1 | 2 | up to 2^16 - 1 |
234 * +----+------+-----+----------------+
235 */
236
237 result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
238 if(result || (actualread != 4)) {
239 failf(data, "Failed to receive GSS-API authentication response.");
240 gss_release_name(&gss_status, &server);
241 gss_delete_sec_context(&gss_status, &gss_context, NULL);
242 return CURLE_COULDNT_CONNECT;
243 }
244
245 /* ignore the first (VER) byte */
246 if(socksreq[1] == 255) { /* status / message type */
247 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
248 socksreq[0], socksreq[1]);
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 if(socksreq[1] != 1) { /* status / messgae type */
255 failf(data, "Invalid GSS-API authentication response type (%d %d).",
256 socksreq[0], socksreq[1]);
257 gss_release_name(&gss_status, &server);
258 gss_delete_sec_context(&gss_status, &gss_context, NULL);
259 return CURLE_COULDNT_CONNECT;
260 }
261
262 memcpy(&us_length, socksreq+2, sizeof(short));
263 us_length = ntohs(us_length);
264
265 gss_recv_token.length=us_length;
266 gss_recv_token.value=malloc(us_length);
267 if(!gss_recv_token.value) {
268 failf(data,
269 "Could not allocate memory for GSS-API authentication "
270 "response token.");
271 gss_release_name(&gss_status, &server);
272 gss_delete_sec_context(&gss_status, &gss_context, NULL);
273 return CURLE_OUT_OF_MEMORY;
274 }
275
276 result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
277 gss_recv_token.length, &actualread);
278
279 if(result || (actualread != us_length)) {
280 failf(data, "Failed to receive GSS-API authentication token.");
281 gss_release_name(&gss_status, &server);
282 gss_release_buffer(&gss_status, &gss_recv_token);
283 gss_delete_sec_context(&gss_status, &gss_context, NULL);
284 return CURLE_COULDNT_CONNECT;
285 }
286
287 gss_token = &gss_recv_token;
288 }
289
290 gss_release_name(&gss_status, &server);
291
292 /* Everything is good so far, user was authenticated! */
293 gss_major_status = gss_inquire_context (&gss_minor_status, gss_context,
294 &gss_client_name, NULL, NULL, NULL,
295 NULL, NULL, NULL);
296 if(check_gss_err(data, gss_major_status,
297 gss_minor_status, "gss_inquire_context")) {
298 gss_delete_sec_context(&gss_status, &gss_context, NULL);
299 gss_release_name(&gss_status, &gss_client_name);
300 failf(data, "Failed to determine user name.");
301 return CURLE_COULDNT_CONNECT;
302 }
303 gss_major_status = gss_display_name(&gss_minor_status, gss_client_name,
304 &gss_send_token, NULL);
305 if(check_gss_err(data, gss_major_status,
306 gss_minor_status, "gss_display_name")) {
307 gss_delete_sec_context(&gss_status, &gss_context, NULL);
308 gss_release_name(&gss_status, &gss_client_name);
309 gss_release_buffer(&gss_status, &gss_send_token);
310 failf(data, "Failed to determine user name.");
311 return CURLE_COULDNT_CONNECT;
312 }
313 user=malloc(gss_send_token.length+1);
314 if(!user) {
315 gss_delete_sec_context(&gss_status, &gss_context, NULL);
316 gss_release_name(&gss_status, &gss_client_name);
317 gss_release_buffer(&gss_status, &gss_send_token);
318 return CURLE_OUT_OF_MEMORY;
319 }
320
321 memcpy(user, gss_send_token.value, gss_send_token.length);
322 user[gss_send_token.length] = '\0';
323 gss_release_name(&gss_status, &gss_client_name);
324 gss_release_buffer(&gss_status, &gss_send_token);
325 infof(data, "SOCKS5 server authencticated user %s with GSS-API.\n",user);
326 free(user);
327 user=NULL;
328
329 /* Do encryption */
330 socksreq[0] = 1; /* GSS-API subnegotiation version */
331 socksreq[1] = 2; /* encryption message type */
332
333 gss_enc = 0; /* no data protection */
334 /* do confidentiality protection if supported */
335 if(gss_ret_flags & GSS_C_CONF_FLAG)
336 gss_enc = 2;
337 /* else do integrity protection */
338 else if(gss_ret_flags & GSS_C_INTEG_FLAG)
339 gss_enc = 1;
340
341 infof(data, "SOCKS5 server supports GSS-API %s data protection.\n",
342 (gss_enc==0)?"no":((gss_enc==1)?"integrity":"confidentiality"));
343 /* force for the moment to no data protection */
344 gss_enc = 0;
345 /*
346 * Sending the encryption type in clear seems wrong. It should be
347 * protected with gss_seal()/gss_wrap(). See RFC1961 extract below
348 * The NEC reference implementations on which this is based is
349 * therefore at fault
350 *
351 * +------+------+------+.......................+
352 * + ver | mtyp | len | token |
353 * +------+------+------+.......................+
354 * + 0x01 | 0x02 | 0x02 | up to 2^16 - 1 octets |
355 * +------+------+------+.......................+
356 *
357 * Where:
358 *
359 * - "ver" is the protocol version number, here 1 to represent the
360 * first version of the SOCKS/GSS-API protocol
361 *
362 * - "mtyp" is the message type, here 2 to represent a protection
363 * -level negotiation message
364 *
365 * - "len" is the length of the "token" field in octets
366 *
367 * - "token" is the GSS-API encapsulated protection level
368 *
369 * The token is produced by encapsulating an octet containing the
370 * required protection level using gss_seal()/gss_wrap() with conf_req
371 * set to FALSE. The token is verified using gss_unseal()/
372 * gss_unwrap().
373 *
374 */
375 if(data->set.socks5_gssapi_nec) {
376 us_length = htons((short)1);
377 memcpy(socksreq+2, &us_length, sizeof(short));
378 }
379 else {
380 gss_send_token.length = 1;
381 gss_send_token.value = malloc(1);
382 if(!gss_send_token.value) {
383 gss_delete_sec_context(&gss_status, &gss_context, NULL);
384 return CURLE_OUT_OF_MEMORY;
385 }
386 memcpy(gss_send_token.value, &gss_enc, 1);
387
388 gss_major_status = gss_wrap(&gss_minor_status, gss_context, 0,
389 GSS_C_QOP_DEFAULT, &gss_send_token,
390 &gss_conf_state, &gss_w_token);
391
392 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_wrap")) {
393 gss_release_buffer(&gss_status, &gss_send_token);
394 gss_release_buffer(&gss_status, &gss_w_token);
395 gss_delete_sec_context(&gss_status, &gss_context, NULL);
396 failf(data, "Failed to wrap GSS-API encryption value into token.");
397 return CURLE_COULDNT_CONNECT;
398 }
399 gss_release_buffer(&gss_status, &gss_send_token);
400
401 us_length = htons((short)gss_w_token.length);
402 memcpy(socksreq+2, &us_length, sizeof(short));
403 }
404
405 code = Curl_write_plain(conn, sock, (char *)socksreq, 4, &written);
406 if(code || (4 != written)) {
407 failf(data, "Failed to send GSS-API encryption request.");
408 gss_release_buffer(&gss_status, &gss_w_token);
409 gss_delete_sec_context(&gss_status, &gss_context, NULL);
410 return CURLE_COULDNT_CONNECT;
411 }
412
413 if(data->set.socks5_gssapi_nec) {
414 memcpy(socksreq, &gss_enc, 1);
415 code = Curl_write_plain(conn, sock, socksreq, 1, &written);
416 if(code || ( 1 != written)) {
417 failf(data, "Failed to send GSS-API encryption type.");
418 gss_delete_sec_context(&gss_status, &gss_context, NULL);
419 return CURLE_COULDNT_CONNECT;
420 }
421 }
422 else {
423 code = Curl_write_plain(conn, sock, (char *)gss_w_token.value,
424 gss_w_token.length, &written);
425 if(code || ((ssize_t)gss_w_token.length != written)) {
426 failf(data, "Failed to send GSS-API encryption type.");
427 gss_release_buffer(&gss_status, &gss_w_token);
428 gss_delete_sec_context(&gss_status, &gss_context, NULL);
429 return CURLE_COULDNT_CONNECT;
430 }
431 gss_release_buffer(&gss_status, &gss_w_token);
432 }
433
434 result=Curl_blockread_all(conn, sock, (char *)socksreq, 4, &actualread);
435 if(result || (actualread != 4)) {
436 failf(data, "Failed to receive GSS-API encryption response.");
437 gss_delete_sec_context(&gss_status, &gss_context, NULL);
438 return CURLE_COULDNT_CONNECT;
439 }
440
441 /* ignore the first (VER) byte */
442 if(socksreq[1] == 255) { /* status / message type */
443 failf(data, "User was rejected by the SOCKS5 server (%d %d).",
444 socksreq[0], socksreq[1]);
445 gss_delete_sec_context(&gss_status, &gss_context, NULL);
446 return CURLE_COULDNT_CONNECT;
447 }
448
449 if(socksreq[1] != 2) { /* status / messgae type */
450 failf(data, "Invalid GSS-API encryption response type (%d %d).",
451 socksreq[0], socksreq[1]);
452 gss_delete_sec_context(&gss_status, &gss_context, NULL);
453 return CURLE_COULDNT_CONNECT;
454 }
455
456 memcpy(&us_length, socksreq+2, sizeof(short));
457 us_length = ntohs(us_length);
458
459 gss_recv_token.length= us_length;
460 gss_recv_token.value=malloc(gss_recv_token.length);
461 if(!gss_recv_token.value) {
462 gss_delete_sec_context(&gss_status, &gss_context, NULL);
463 return CURLE_OUT_OF_MEMORY;
464 }
465 result=Curl_blockread_all(conn, sock, (char *)gss_recv_token.value,
466 gss_recv_token.length, &actualread);
467
468 if(result || (actualread != us_length)) {
469 failf(data, "Failed to receive GSS-API encryptrion type.");
470 gss_release_buffer(&gss_status, &gss_recv_token);
471 gss_delete_sec_context(&gss_status, &gss_context, NULL);
472 return CURLE_COULDNT_CONNECT;
473 }
474
475 if(!data->set.socks5_gssapi_nec) {
476 gss_major_status = gss_unwrap(&gss_minor_status, gss_context,
477 &gss_recv_token, &gss_w_token,
478 0, GSS_C_QOP_DEFAULT);
479
480 if(check_gss_err(data, gss_major_status, gss_minor_status, "gss_unwrap")) {
481 gss_release_buffer(&gss_status, &gss_recv_token);
482 gss_release_buffer(&gss_status, &gss_w_token);
483 gss_delete_sec_context(&gss_status, &gss_context, NULL);
484 failf(data, "Failed to unwrap GSS-API encryption value into token.");
485 return CURLE_COULDNT_CONNECT;
486 }
487 gss_release_buffer(&gss_status, &gss_recv_token);
488
489 if(gss_w_token.length != 1) {
490 failf(data, "Invalid GSS-API encryption response length (%d).",
491 gss_w_token.length);
492 gss_release_buffer(&gss_status, &gss_w_token);
493 gss_delete_sec_context(&gss_status, &gss_context, NULL);
494 return CURLE_COULDNT_CONNECT;
495 }
496
497 memcpy(socksreq, gss_w_token.value, gss_w_token.length);
498 gss_release_buffer(&gss_status, &gss_w_token);
499 }
500 else {
501 if(gss_recv_token.length != 1) {
502 failf(data, "Invalid GSS-API encryption response length (%d).",
503 gss_recv_token.length);
504 gss_release_buffer(&gss_status, &gss_recv_token);
505 gss_delete_sec_context(&gss_status, &gss_context, NULL);
506 return CURLE_COULDNT_CONNECT;
507 }
508
509 memcpy(socksreq, gss_recv_token.value, gss_recv_token.length);
510 gss_release_buffer(&gss_status, &gss_recv_token);
511 }
512
513 infof(data, "SOCKS5 access with%s protection granted.\n",
514 (socksreq[0]==0)?"out GSS-API data":
515 ((socksreq[0]==1)?" GSS-API integrity":" GSS-API confidentiality"));
516
517 conn->socks5_gssapi_enctype = socksreq[0];
518 if(socksreq[0] == 0)
519 gss_delete_sec_context(&gss_status, &gss_context, NULL);
520
521 return CURLE_OK;
522 }
523
524 #endif /* HAVE_GSSAPI && !CURL_DISABLE_PROXY */
525