root / ui / vnc-auth-sasl.c @ 4d5b97da
History | View | Annotate | Download (18.6 kB)
1 |
/*
|
---|---|
2 |
* QEMU VNC display driver: SASL auth protocol
|
3 |
*
|
4 |
* Copyright (C) 2009 Red Hat, Inc
|
5 |
*
|
6 |
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
7 |
* of this software and associated documentation files (the "Software"), to deal
|
8 |
* in the Software without restriction, including without limitation the rights
|
9 |
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
10 |
* copies of the Software, and to permit persons to whom the Software is
|
11 |
* furnished to do so, subject to the following conditions:
|
12 |
*
|
13 |
* The above copyright notice and this permission notice shall be included in
|
14 |
* all copies or substantial portions of the Software.
|
15 |
*
|
16 |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
17 |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
18 |
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
19 |
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
20 |
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
21 |
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
22 |
* THE SOFTWARE.
|
23 |
*/
|
24 |
|
25 |
#include "vnc.h" |
26 |
|
27 |
/* Max amount of data we send/recv for SASL steps to prevent DOS */
|
28 |
#define SASL_DATA_MAX_LEN (1024 * 1024) |
29 |
|
30 |
|
31 |
void vnc_sasl_client_cleanup(VncState *vs)
|
32 |
{ |
33 |
if (vs->sasl.conn) {
|
34 |
vs->sasl.runSSF = false;
|
35 |
vs->sasl.wantSSF = false;
|
36 |
vs->sasl.waitWriteSSF = 0;
|
37 |
vs->sasl.encodedLength = vs->sasl.encodedOffset = 0;
|
38 |
vs->sasl.encoded = NULL;
|
39 |
g_free(vs->sasl.username); |
40 |
g_free(vs->sasl.mechlist); |
41 |
vs->sasl.username = vs->sasl.mechlist = NULL;
|
42 |
sasl_dispose(&vs->sasl.conn); |
43 |
vs->sasl.conn = NULL;
|
44 |
} |
45 |
} |
46 |
|
47 |
|
48 |
long vnc_client_write_sasl(VncState *vs)
|
49 |
{ |
50 |
long ret;
|
51 |
|
52 |
VNC_DEBUG("Write SASL: Pending output %p size %zd offset %zd "
|
53 |
"Encoded: %p size %d offset %d\n",
|
54 |
vs->output.buffer, vs->output.capacity, vs->output.offset, |
55 |
vs->sasl.encoded, vs->sasl.encodedLength, vs->sasl.encodedOffset); |
56 |
|
57 |
if (!vs->sasl.encoded) {
|
58 |
int err;
|
59 |
err = sasl_encode(vs->sasl.conn, |
60 |
(char *)vs->output.buffer,
|
61 |
vs->output.offset, |
62 |
(const char **)&vs->sasl.encoded, |
63 |
&vs->sasl.encodedLength); |
64 |
if (err != SASL_OK)
|
65 |
return vnc_client_io_error(vs, -1, EIO); |
66 |
|
67 |
vs->sasl.encodedOffset = 0;
|
68 |
} |
69 |
|
70 |
ret = vnc_client_write_buf(vs, |
71 |
vs->sasl.encoded + vs->sasl.encodedOffset, |
72 |
vs->sasl.encodedLength - vs->sasl.encodedOffset); |
73 |
if (!ret)
|
74 |
return 0; |
75 |
|
76 |
vs->sasl.encodedOffset += ret; |
77 |
if (vs->sasl.encodedOffset == vs->sasl.encodedLength) {
|
78 |
vs->output.offset = 0;
|
79 |
vs->sasl.encoded = NULL;
|
80 |
vs->sasl.encodedOffset = vs->sasl.encodedLength = 0;
|
81 |
} |
82 |
|
83 |
/* Can't merge this block with one above, because
|
84 |
* someone might have written more unencrypted
|
85 |
* data in vs->output while we were processing
|
86 |
* SASL encoded output
|
87 |
*/
|
88 |
if (vs->output.offset == 0) { |
89 |
qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs); |
90 |
} |
91 |
|
92 |
return ret;
|
93 |
} |
94 |
|
95 |
|
96 |
long vnc_client_read_sasl(VncState *vs)
|
97 |
{ |
98 |
long ret;
|
99 |
uint8_t encoded[4096];
|
100 |
const char *decoded; |
101 |
unsigned int decodedLen; |
102 |
int err;
|
103 |
|
104 |
ret = vnc_client_read_buf(vs, encoded, sizeof(encoded));
|
105 |
if (!ret)
|
106 |
return 0; |
107 |
|
108 |
err = sasl_decode(vs->sasl.conn, |
109 |
(char *)encoded, ret,
|
110 |
&decoded, &decodedLen); |
111 |
|
112 |
if (err != SASL_OK)
|
113 |
return vnc_client_io_error(vs, -1, -EIO); |
114 |
VNC_DEBUG("Read SASL Encoded %p size %ld Decoded %p size %d\n",
|
115 |
encoded, ret, decoded, decodedLen); |
116 |
buffer_reserve(&vs->input, decodedLen); |
117 |
buffer_append(&vs->input, decoded, decodedLen); |
118 |
return decodedLen;
|
119 |
} |
120 |
|
121 |
|
122 |
static int vnc_auth_sasl_check_access(VncState *vs) |
123 |
{ |
124 |
const void *val; |
125 |
int err;
|
126 |
int allow;
|
127 |
|
128 |
err = sasl_getprop(vs->sasl.conn, SASL_USERNAME, &val); |
129 |
if (err != SASL_OK) {
|
130 |
VNC_DEBUG("cannot query SASL username on connection %d (%s), denying access\n",
|
131 |
err, sasl_errstring(err, NULL, NULL)); |
132 |
return -1; |
133 |
} |
134 |
if (val == NULL) { |
135 |
VNC_DEBUG("no client username was found, denying access\n");
|
136 |
return -1; |
137 |
} |
138 |
VNC_DEBUG("SASL client username %s\n", (const char *)val); |
139 |
|
140 |
vs->sasl.username = g_strdup((const char*)val); |
141 |
|
142 |
if (vs->vd->sasl.acl == NULL) { |
143 |
VNC_DEBUG("no ACL activated, allowing access\n");
|
144 |
return 0; |
145 |
} |
146 |
|
147 |
allow = qemu_acl_party_is_allowed(vs->vd->sasl.acl, vs->sasl.username); |
148 |
|
149 |
VNC_DEBUG("SASL client %s %s by ACL\n", vs->sasl.username,
|
150 |
allow ? "allowed" : "denied"); |
151 |
return allow ? 0 : -1; |
152 |
} |
153 |
|
154 |
static int vnc_auth_sasl_check_ssf(VncState *vs) |
155 |
{ |
156 |
const void *val; |
157 |
int err, ssf;
|
158 |
|
159 |
if (!vs->sasl.wantSSF)
|
160 |
return 1; |
161 |
|
162 |
err = sasl_getprop(vs->sasl.conn, SASL_SSF, &val); |
163 |
if (err != SASL_OK)
|
164 |
return 0; |
165 |
|
166 |
ssf = *(const int *)val; |
167 |
VNC_DEBUG("negotiated an SSF of %d\n", ssf);
|
168 |
if (ssf < 56) |
169 |
return 0; /* 56 is good for Kerberos */ |
170 |
|
171 |
/* Only setup for read initially, because we're about to send an RPC
|
172 |
* reply which must be in plain text. When the next incoming RPC
|
173 |
* arrives, we'll switch on writes too
|
174 |
*
|
175 |
* cf qemudClientReadSASL in qemud.c
|
176 |
*/
|
177 |
vs->sasl.runSSF = 1;
|
178 |
|
179 |
/* We have a SSF that's good enough */
|
180 |
return 1; |
181 |
} |
182 |
|
183 |
/*
|
184 |
* Step Msg
|
185 |
*
|
186 |
* Input from client:
|
187 |
*
|
188 |
* u32 clientin-length
|
189 |
* u8-array clientin-string
|
190 |
*
|
191 |
* Output to client:
|
192 |
*
|
193 |
* u32 serverout-length
|
194 |
* u8-array serverout-strin
|
195 |
* u8 continue
|
196 |
*/
|
197 |
|
198 |
static int protocol_client_auth_sasl_step_len(VncState *vs, uint8_t *data, size_t len); |
199 |
|
200 |
static int protocol_client_auth_sasl_step(VncState *vs, uint8_t *data, size_t len) |
201 |
{ |
202 |
uint32_t datalen = len; |
203 |
const char *serverout; |
204 |
unsigned int serveroutlen; |
205 |
int err;
|
206 |
char *clientdata = NULL; |
207 |
|
208 |
/* NB, distinction of NULL vs "" is *critical* in SASL */
|
209 |
if (datalen) {
|
210 |
clientdata = (char*)data;
|
211 |
clientdata[datalen-1] = '\0'; /* Wire includes '\0', but make sure */ |
212 |
datalen--; /* Don't count NULL byte when passing to _start() */
|
213 |
} |
214 |
|
215 |
VNC_DEBUG("Step using SASL Data %p (%d bytes)\n",
|
216 |
clientdata, datalen); |
217 |
err = sasl_server_step(vs->sasl.conn, |
218 |
clientdata, |
219 |
datalen, |
220 |
&serverout, |
221 |
&serveroutlen); |
222 |
if (err != SASL_OK &&
|
223 |
err != SASL_CONTINUE) { |
224 |
VNC_DEBUG("sasl step failed %d (%s)\n",
|
225 |
err, sasl_errdetail(vs->sasl.conn)); |
226 |
sasl_dispose(&vs->sasl.conn); |
227 |
vs->sasl.conn = NULL;
|
228 |
goto authabort;
|
229 |
} |
230 |
|
231 |
if (serveroutlen > SASL_DATA_MAX_LEN) {
|
232 |
VNC_DEBUG("sasl step reply data too long %d\n",
|
233 |
serveroutlen); |
234 |
sasl_dispose(&vs->sasl.conn); |
235 |
vs->sasl.conn = NULL;
|
236 |
goto authabort;
|
237 |
} |
238 |
|
239 |
VNC_DEBUG("SASL return data %d bytes, nil; %d\n",
|
240 |
serveroutlen, serverout ? 0 : 1); |
241 |
|
242 |
if (serveroutlen) {
|
243 |
vnc_write_u32(vs, serveroutlen + 1);
|
244 |
vnc_write(vs, serverout, serveroutlen + 1);
|
245 |
} else {
|
246 |
vnc_write_u32(vs, 0);
|
247 |
} |
248 |
|
249 |
/* Whether auth is complete */
|
250 |
vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1); |
251 |
|
252 |
if (err == SASL_CONTINUE) {
|
253 |
VNC_DEBUG("%s", "Authentication must continue\n"); |
254 |
/* Wait for step length */
|
255 |
vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4);
|
256 |
} else {
|
257 |
if (!vnc_auth_sasl_check_ssf(vs)) {
|
258 |
VNC_DEBUG("Authentication rejected for weak SSF %d\n", vs->csock);
|
259 |
goto authreject;
|
260 |
} |
261 |
|
262 |
/* Check username whitelist ACL */
|
263 |
if (vnc_auth_sasl_check_access(vs) < 0) { |
264 |
VNC_DEBUG("Authentication rejected for ACL %d\n", vs->csock);
|
265 |
goto authreject;
|
266 |
} |
267 |
|
268 |
VNC_DEBUG("Authentication successful %d\n", vs->csock);
|
269 |
vnc_write_u32(vs, 0); /* Accept auth */ |
270 |
/*
|
271 |
* Delay writing in SSF encoded mode until pending output
|
272 |
* buffer is written
|
273 |
*/
|
274 |
if (vs->sasl.runSSF)
|
275 |
vs->sasl.waitWriteSSF = vs->output.offset; |
276 |
start_client_init(vs); |
277 |
} |
278 |
|
279 |
return 0; |
280 |
|
281 |
authreject:
|
282 |
vnc_write_u32(vs, 1); /* Reject auth */ |
283 |
vnc_write_u32(vs, sizeof("Authentication failed")); |
284 |
vnc_write(vs, "Authentication failed", sizeof("Authentication failed")); |
285 |
vnc_flush(vs); |
286 |
vnc_client_error(vs); |
287 |
return -1; |
288 |
|
289 |
authabort:
|
290 |
vnc_client_error(vs); |
291 |
return -1; |
292 |
} |
293 |
|
294 |
static int protocol_client_auth_sasl_step_len(VncState *vs, uint8_t *data, size_t len) |
295 |
{ |
296 |
uint32_t steplen = read_u32(data, 0);
|
297 |
VNC_DEBUG("Got client step len %d\n", steplen);
|
298 |
if (steplen > SASL_DATA_MAX_LEN) {
|
299 |
VNC_DEBUG("Too much SASL data %d\n", steplen);
|
300 |
vnc_client_error(vs); |
301 |
return -1; |
302 |
} |
303 |
|
304 |
if (steplen == 0) |
305 |
return protocol_client_auth_sasl_step(vs, NULL, 0); |
306 |
else
|
307 |
vnc_read_when(vs, protocol_client_auth_sasl_step, steplen); |
308 |
return 0; |
309 |
} |
310 |
|
311 |
/*
|
312 |
* Start Msg
|
313 |
*
|
314 |
* Input from client:
|
315 |
*
|
316 |
* u32 clientin-length
|
317 |
* u8-array clientin-string
|
318 |
*
|
319 |
* Output to client:
|
320 |
*
|
321 |
* u32 serverout-length
|
322 |
* u8-array serverout-strin
|
323 |
* u8 continue
|
324 |
*/
|
325 |
|
326 |
#define SASL_DATA_MAX_LEN (1024 * 1024) |
327 |
|
328 |
static int protocol_client_auth_sasl_start(VncState *vs, uint8_t *data, size_t len) |
329 |
{ |
330 |
uint32_t datalen = len; |
331 |
const char *serverout; |
332 |
unsigned int serveroutlen; |
333 |
int err;
|
334 |
char *clientdata = NULL; |
335 |
|
336 |
/* NB, distinction of NULL vs "" is *critical* in SASL */
|
337 |
if (datalen) {
|
338 |
clientdata = (char*)data;
|
339 |
clientdata[datalen-1] = '\0'; /* Should be on wire, but make sure */ |
340 |
datalen--; /* Don't count NULL byte when passing to _start() */
|
341 |
} |
342 |
|
343 |
VNC_DEBUG("Start SASL auth with mechanism %s. Data %p (%d bytes)\n",
|
344 |
vs->sasl.mechlist, clientdata, datalen); |
345 |
err = sasl_server_start(vs->sasl.conn, |
346 |
vs->sasl.mechlist, |
347 |
clientdata, |
348 |
datalen, |
349 |
&serverout, |
350 |
&serveroutlen); |
351 |
if (err != SASL_OK &&
|
352 |
err != SASL_CONTINUE) { |
353 |
VNC_DEBUG("sasl start failed %d (%s)\n",
|
354 |
err, sasl_errdetail(vs->sasl.conn)); |
355 |
sasl_dispose(&vs->sasl.conn); |
356 |
vs->sasl.conn = NULL;
|
357 |
goto authabort;
|
358 |
} |
359 |
if (serveroutlen > SASL_DATA_MAX_LEN) {
|
360 |
VNC_DEBUG("sasl start reply data too long %d\n",
|
361 |
serveroutlen); |
362 |
sasl_dispose(&vs->sasl.conn); |
363 |
vs->sasl.conn = NULL;
|
364 |
goto authabort;
|
365 |
} |
366 |
|
367 |
VNC_DEBUG("SASL return data %d bytes, nil; %d\n",
|
368 |
serveroutlen, serverout ? 0 : 1); |
369 |
|
370 |
if (serveroutlen) {
|
371 |
vnc_write_u32(vs, serveroutlen + 1);
|
372 |
vnc_write(vs, serverout, serveroutlen + 1);
|
373 |
} else {
|
374 |
vnc_write_u32(vs, 0);
|
375 |
} |
376 |
|
377 |
/* Whether auth is complete */
|
378 |
vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1); |
379 |
|
380 |
if (err == SASL_CONTINUE) {
|
381 |
VNC_DEBUG("%s", "Authentication must continue\n"); |
382 |
/* Wait for step length */
|
383 |
vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4);
|
384 |
} else {
|
385 |
if (!vnc_auth_sasl_check_ssf(vs)) {
|
386 |
VNC_DEBUG("Authentication rejected for weak SSF %d\n", vs->csock);
|
387 |
goto authreject;
|
388 |
} |
389 |
|
390 |
/* Check username whitelist ACL */
|
391 |
if (vnc_auth_sasl_check_access(vs) < 0) { |
392 |
VNC_DEBUG("Authentication rejected for ACL %d\n", vs->csock);
|
393 |
goto authreject;
|
394 |
} |
395 |
|
396 |
VNC_DEBUG("Authentication successful %d\n", vs->csock);
|
397 |
vnc_write_u32(vs, 0); /* Accept auth */ |
398 |
start_client_init(vs); |
399 |
} |
400 |
|
401 |
return 0; |
402 |
|
403 |
authreject:
|
404 |
vnc_write_u32(vs, 1); /* Reject auth */ |
405 |
vnc_write_u32(vs, sizeof("Authentication failed")); |
406 |
vnc_write(vs, "Authentication failed", sizeof("Authentication failed")); |
407 |
vnc_flush(vs); |
408 |
vnc_client_error(vs); |
409 |
return -1; |
410 |
|
411 |
authabort:
|
412 |
vnc_client_error(vs); |
413 |
return -1; |
414 |
} |
415 |
|
416 |
static int protocol_client_auth_sasl_start_len(VncState *vs, uint8_t *data, size_t len) |
417 |
{ |
418 |
uint32_t startlen = read_u32(data, 0);
|
419 |
VNC_DEBUG("Got client start len %d\n", startlen);
|
420 |
if (startlen > SASL_DATA_MAX_LEN) {
|
421 |
VNC_DEBUG("Too much SASL data %d\n", startlen);
|
422 |
vnc_client_error(vs); |
423 |
return -1; |
424 |
} |
425 |
|
426 |
if (startlen == 0) |
427 |
return protocol_client_auth_sasl_start(vs, NULL, 0); |
428 |
|
429 |
vnc_read_when(vs, protocol_client_auth_sasl_start, startlen); |
430 |
return 0; |
431 |
} |
432 |
|
433 |
static int protocol_client_auth_sasl_mechname(VncState *vs, uint8_t *data, size_t len) |
434 |
{ |
435 |
char *mechname = g_malloc(len + 1); |
436 |
strncpy(mechname, (char*)data, len);
|
437 |
mechname[len] = '\0';
|
438 |
VNC_DEBUG("Got client mechname '%s' check against '%s'\n",
|
439 |
mechname, vs->sasl.mechlist); |
440 |
|
441 |
if (strncmp(vs->sasl.mechlist, mechname, len) == 0) { |
442 |
if (vs->sasl.mechlist[len] != '\0' && |
443 |
vs->sasl.mechlist[len] != ',') {
|
444 |
VNC_DEBUG("One %d", vs->sasl.mechlist[len]);
|
445 |
goto fail;
|
446 |
} |
447 |
} else {
|
448 |
char *offset = strstr(vs->sasl.mechlist, mechname);
|
449 |
VNC_DEBUG("Two %p\n", offset);
|
450 |
if (!offset) {
|
451 |
goto fail;
|
452 |
} |
453 |
VNC_DEBUG("Two '%s'\n", offset);
|
454 |
if (offset[-1] != ',' || |
455 |
(offset[len] != '\0'&&
|
456 |
offset[len] != ',')) {
|
457 |
goto fail;
|
458 |
} |
459 |
} |
460 |
|
461 |
g_free(vs->sasl.mechlist); |
462 |
vs->sasl.mechlist = mechname; |
463 |
|
464 |
VNC_DEBUG("Validated mechname '%s'\n", mechname);
|
465 |
vnc_read_when(vs, protocol_client_auth_sasl_start_len, 4);
|
466 |
return 0; |
467 |
|
468 |
fail:
|
469 |
vnc_client_error(vs); |
470 |
g_free(mechname); |
471 |
return -1; |
472 |
} |
473 |
|
474 |
static int protocol_client_auth_sasl_mechname_len(VncState *vs, uint8_t *data, size_t len) |
475 |
{ |
476 |
uint32_t mechlen = read_u32(data, 0);
|
477 |
VNC_DEBUG("Got client mechname len %d\n", mechlen);
|
478 |
if (mechlen > 100) { |
479 |
VNC_DEBUG("Too long SASL mechname data %d\n", mechlen);
|
480 |
vnc_client_error(vs); |
481 |
return -1; |
482 |
} |
483 |
if (mechlen < 1) { |
484 |
VNC_DEBUG("Too short SASL mechname %d\n", mechlen);
|
485 |
vnc_client_error(vs); |
486 |
return -1; |
487 |
} |
488 |
vnc_read_when(vs, protocol_client_auth_sasl_mechname,mechlen); |
489 |
return 0; |
490 |
} |
491 |
|
492 |
void start_auth_sasl(VncState *vs)
|
493 |
{ |
494 |
const char *mechlist = NULL; |
495 |
sasl_security_properties_t secprops; |
496 |
int err;
|
497 |
char *localAddr, *remoteAddr;
|
498 |
int mechlistlen;
|
499 |
|
500 |
VNC_DEBUG("Initialize SASL auth %d\n", vs->csock);
|
501 |
|
502 |
/* Get local & remote client addresses in form IPADDR;PORT */
|
503 |
if (!(localAddr = vnc_socket_local_addr("%s;%s", vs->csock))) |
504 |
goto authabort;
|
505 |
|
506 |
if (!(remoteAddr = vnc_socket_remote_addr("%s;%s", vs->csock))) { |
507 |
g_free(localAddr); |
508 |
goto authabort;
|
509 |
} |
510 |
|
511 |
err = sasl_server_new("vnc",
|
512 |
NULL, /* FQDN - just delegates to gethostname */ |
513 |
NULL, /* User realm */ |
514 |
localAddr, |
515 |
remoteAddr, |
516 |
NULL, /* Callbacks, not needed */ |
517 |
SASL_SUCCESS_DATA, |
518 |
&vs->sasl.conn); |
519 |
g_free(localAddr); |
520 |
g_free(remoteAddr); |
521 |
localAddr = remoteAddr = NULL;
|
522 |
|
523 |
if (err != SASL_OK) {
|
524 |
VNC_DEBUG("sasl context setup failed %d (%s)",
|
525 |
err, sasl_errstring(err, NULL, NULL)); |
526 |
vs->sasl.conn = NULL;
|
527 |
goto authabort;
|
528 |
} |
529 |
|
530 |
#ifdef CONFIG_VNC_TLS
|
531 |
/* Inform SASL that we've got an external SSF layer from TLS/x509 */
|
532 |
if (vs->auth == VNC_AUTH_VENCRYPT &&
|
533 |
vs->subauth == VNC_AUTH_VENCRYPT_X509SASL) { |
534 |
gnutls_cipher_algorithm_t cipher; |
535 |
sasl_ssf_t ssf; |
536 |
|
537 |
cipher = gnutls_cipher_get(vs->tls.session); |
538 |
if (!(ssf = (sasl_ssf_t)gnutls_cipher_get_key_size(cipher))) {
|
539 |
VNC_DEBUG("%s", "cannot TLS get cipher size\n"); |
540 |
sasl_dispose(&vs->sasl.conn); |
541 |
vs->sasl.conn = NULL;
|
542 |
goto authabort;
|
543 |
} |
544 |
ssf *= 8; /* tls key size is bytes, sasl wants bits */ |
545 |
|
546 |
err = sasl_setprop(vs->sasl.conn, SASL_SSF_EXTERNAL, &ssf); |
547 |
if (err != SASL_OK) {
|
548 |
VNC_DEBUG("cannot set SASL external SSF %d (%s)\n",
|
549 |
err, sasl_errstring(err, NULL, NULL)); |
550 |
sasl_dispose(&vs->sasl.conn); |
551 |
vs->sasl.conn = NULL;
|
552 |
goto authabort;
|
553 |
} |
554 |
} else
|
555 |
#endif /* CONFIG_VNC_TLS */ |
556 |
vs->sasl.wantSSF = 1;
|
557 |
|
558 |
memset (&secprops, 0, sizeof secprops); |
559 |
/* Inform SASL that we've got an external SSF layer from TLS */
|
560 |
if (strncmp(vs->vd->display, "unix:", 5) == 0 |
561 |
#ifdef CONFIG_VNC_TLS
|
562 |
/* Disable SSF, if using TLS+x509+SASL only. TLS without x509
|
563 |
is not sufficiently strong */
|
564 |
|| (vs->auth == VNC_AUTH_VENCRYPT && |
565 |
vs->subauth == VNC_AUTH_VENCRYPT_X509SASL) |
566 |
#endif /* CONFIG_VNC_TLS */ |
567 |
) { |
568 |
/* If we've got TLS or UNIX domain sock, we don't care about SSF */
|
569 |
secprops.min_ssf = 0;
|
570 |
secprops.max_ssf = 0;
|
571 |
secprops.maxbufsize = 8192;
|
572 |
secprops.security_flags = 0;
|
573 |
} else {
|
574 |
/* Plain TCP, better get an SSF layer */
|
575 |
secprops.min_ssf = 56; /* Good enough to require kerberos */ |
576 |
secprops.max_ssf = 100000; /* Arbitrary big number */ |
577 |
secprops.maxbufsize = 8192;
|
578 |
/* Forbid any anonymous or trivially crackable auth */
|
579 |
secprops.security_flags = |
580 |
SASL_SEC_NOANONYMOUS | SASL_SEC_NOPLAINTEXT; |
581 |
} |
582 |
|
583 |
err = sasl_setprop(vs->sasl.conn, SASL_SEC_PROPS, &secprops); |
584 |
if (err != SASL_OK) {
|
585 |
VNC_DEBUG("cannot set SASL security props %d (%s)\n",
|
586 |
err, sasl_errstring(err, NULL, NULL)); |
587 |
sasl_dispose(&vs->sasl.conn); |
588 |
vs->sasl.conn = NULL;
|
589 |
goto authabort;
|
590 |
} |
591 |
|
592 |
err = sasl_listmech(vs->sasl.conn, |
593 |
NULL, /* Don't need to set user */ |
594 |
"", /* Prefix */ |
595 |
",", /* Separator */ |
596 |
"", /* Suffix */ |
597 |
&mechlist, |
598 |
NULL,
|
599 |
NULL);
|
600 |
if (err != SASL_OK) {
|
601 |
VNC_DEBUG("cannot list SASL mechanisms %d (%s)\n",
|
602 |
err, sasl_errdetail(vs->sasl.conn)); |
603 |
sasl_dispose(&vs->sasl.conn); |
604 |
vs->sasl.conn = NULL;
|
605 |
goto authabort;
|
606 |
} |
607 |
VNC_DEBUG("Available mechanisms for client: '%s'\n", mechlist);
|
608 |
|
609 |
vs->sasl.mechlist = g_strdup(mechlist); |
610 |
mechlistlen = strlen(mechlist); |
611 |
vnc_write_u32(vs, mechlistlen); |
612 |
vnc_write(vs, mechlist, mechlistlen); |
613 |
vnc_flush(vs); |
614 |
|
615 |
VNC_DEBUG("Wait for client mechname length\n");
|
616 |
vnc_read_when(vs, protocol_client_auth_sasl_mechname_len, 4);
|
617 |
|
618 |
return;
|
619 |
|
620 |
authabort:
|
621 |
vnc_client_error(vs); |
622 |
} |
623 |
|
624 |
|