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Commit | Line | Data |
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274b6fcc AL |
1 | /* |
2 | * QEMU VNC display driver: TLS helpers | |
3 | * | |
4 | * Copyright (C) 2006 Anthony Liguori <[email protected]> | |
5 | * Copyright (C) 2006 Fabrice Bellard | |
6 | * Copyright (C) 2009 Red Hat, Inc | |
7 | * | |
8 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
9 | * of this software and associated documentation files (the "Software"), to deal | |
10 | * in the Software without restriction, including without limitation the rights | |
11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
12 | * copies of the Software, and to permit persons to whom the Software is | |
13 | * furnished to do so, subject to the following conditions: | |
14 | * | |
15 | * The above copyright notice and this permission notice shall be included in | |
16 | * all copies or substantial portions of the Software. | |
17 | * | |
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
21 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
24 | * THE SOFTWARE. | |
25 | */ | |
26 | ||
de7890db | 27 | #include "qemu-x509.h" |
274b6fcc AL |
28 | #include "vnc.h" |
29 | #include "qemu_socket.h" | |
30 | ||
31 | #if defined(_VNC_DEBUG) && _VNC_DEBUG >= 2 | |
32 | /* Very verbose, so only enabled for _VNC_DEBUG >= 2 */ | |
33 | static void vnc_debug_gnutls_log(int level, const char* str) { | |
34 | VNC_DEBUG("%d %s", level, str); | |
35 | } | |
36 | #endif /* defined(_VNC_DEBUG) && _VNC_DEBUG >= 2 */ | |
37 | ||
38 | ||
39 | #define DH_BITS 1024 | |
40 | static gnutls_dh_params_t dh_params; | |
41 | ||
42 | static int vnc_tls_initialize(void) | |
43 | { | |
44 | static int tlsinitialized = 0; | |
45 | ||
46 | if (tlsinitialized) | |
47 | return 1; | |
48 | ||
49 | if (gnutls_global_init () < 0) | |
50 | return 0; | |
51 | ||
d69eba24 | 52 | /* XXX ought to re-generate diffie-hellman params periodically */ |
274b6fcc AL |
53 | if (gnutls_dh_params_init (&dh_params) < 0) |
54 | return 0; | |
55 | if (gnutls_dh_params_generate2 (dh_params, DH_BITS) < 0) | |
56 | return 0; | |
57 | ||
58 | #if defined(_VNC_DEBUG) && _VNC_DEBUG >= 2 | |
59 | gnutls_global_set_log_level(10); | |
60 | gnutls_global_set_log_function(vnc_debug_gnutls_log); | |
61 | #endif | |
62 | ||
63 | tlsinitialized = 1; | |
64 | ||
65 | return 1; | |
66 | } | |
67 | ||
68 | static ssize_t vnc_tls_push(gnutls_transport_ptr_t transport, | |
69 | const void *data, | |
70 | size_t len) { | |
71 | struct VncState *vs = (struct VncState *)transport; | |
72 | int ret; | |
73 | ||
74 | retry: | |
75 | ret = send(vs->csock, data, len, 0); | |
76 | if (ret < 0) { | |
77 | if (errno == EINTR) | |
78 | goto retry; | |
79 | return -1; | |
80 | } | |
81 | return ret; | |
82 | } | |
83 | ||
84 | ||
85 | static ssize_t vnc_tls_pull(gnutls_transport_ptr_t transport, | |
86 | void *data, | |
87 | size_t len) { | |
88 | struct VncState *vs = (struct VncState *)transport; | |
89 | int ret; | |
90 | ||
91 | retry: | |
00aa0040 | 92 | ret = qemu_recv(vs->csock, data, len, 0); |
274b6fcc AL |
93 | if (ret < 0) { |
94 | if (errno == EINTR) | |
95 | goto retry; | |
96 | return -1; | |
97 | } | |
98 | return ret; | |
99 | } | |
100 | ||
101 | ||
102 | static gnutls_anon_server_credentials vnc_tls_initialize_anon_cred(void) | |
103 | { | |
104 | gnutls_anon_server_credentials anon_cred; | |
105 | int ret; | |
106 | ||
107 | if ((ret = gnutls_anon_allocate_server_credentials(&anon_cred)) < 0) { | |
108 | VNC_DEBUG("Cannot allocate credentials %s\n", gnutls_strerror(ret)); | |
109 | return NULL; | |
110 | } | |
111 | ||
112 | gnutls_anon_set_server_dh_params(anon_cred, dh_params); | |
113 | ||
114 | return anon_cred; | |
115 | } | |
116 | ||
117 | ||
118 | static gnutls_certificate_credentials_t vnc_tls_initialize_x509_cred(VncDisplay *vd) | |
119 | { | |
120 | gnutls_certificate_credentials_t x509_cred; | |
121 | int ret; | |
122 | ||
123 | if (!vd->tls.x509cacert) { | |
124 | VNC_DEBUG("No CA x509 certificate specified\n"); | |
125 | return NULL; | |
126 | } | |
127 | if (!vd->tls.x509cert) { | |
128 | VNC_DEBUG("No server x509 certificate specified\n"); | |
129 | return NULL; | |
130 | } | |
131 | if (!vd->tls.x509key) { | |
132 | VNC_DEBUG("No server private key specified\n"); | |
133 | return NULL; | |
134 | } | |
135 | ||
136 | if ((ret = gnutls_certificate_allocate_credentials(&x509_cred)) < 0) { | |
137 | VNC_DEBUG("Cannot allocate credentials %s\n", gnutls_strerror(ret)); | |
138 | return NULL; | |
139 | } | |
140 | if ((ret = gnutls_certificate_set_x509_trust_file(x509_cred, | |
141 | vd->tls.x509cacert, | |
142 | GNUTLS_X509_FMT_PEM)) < 0) { | |
143 | VNC_DEBUG("Cannot load CA certificate %s\n", gnutls_strerror(ret)); | |
144 | gnutls_certificate_free_credentials(x509_cred); | |
145 | return NULL; | |
146 | } | |
147 | ||
148 | if ((ret = gnutls_certificate_set_x509_key_file (x509_cred, | |
149 | vd->tls.x509cert, | |
150 | vd->tls.x509key, | |
151 | GNUTLS_X509_FMT_PEM)) < 0) { | |
152 | VNC_DEBUG("Cannot load certificate & key %s\n", gnutls_strerror(ret)); | |
153 | gnutls_certificate_free_credentials(x509_cred); | |
154 | return NULL; | |
155 | } | |
156 | ||
157 | if (vd->tls.x509cacrl) { | |
158 | if ((ret = gnutls_certificate_set_x509_crl_file(x509_cred, | |
159 | vd->tls.x509cacrl, | |
160 | GNUTLS_X509_FMT_PEM)) < 0) { | |
161 | VNC_DEBUG("Cannot load CRL %s\n", gnutls_strerror(ret)); | |
162 | gnutls_certificate_free_credentials(x509_cred); | |
163 | return NULL; | |
164 | } | |
165 | } | |
166 | ||
167 | gnutls_certificate_set_dh_params (x509_cred, dh_params); | |
168 | ||
169 | return x509_cred; | |
170 | } | |
171 | ||
172 | ||
173 | int vnc_tls_validate_certificate(struct VncState *vs) | |
174 | { | |
175 | int ret; | |
176 | unsigned int status; | |
177 | const gnutls_datum_t *certs; | |
178 | unsigned int nCerts, i; | |
179 | time_t now; | |
180 | ||
181 | VNC_DEBUG("Validating client certificate\n"); | |
182 | if ((ret = gnutls_certificate_verify_peers2 (vs->tls.session, &status)) < 0) { | |
183 | VNC_DEBUG("Verify failed %s\n", gnutls_strerror(ret)); | |
184 | return -1; | |
185 | } | |
186 | ||
187 | if ((now = time(NULL)) == ((time_t)-1)) { | |
188 | return -1; | |
189 | } | |
190 | ||
191 | if (status != 0) { | |
192 | if (status & GNUTLS_CERT_INVALID) | |
193 | VNC_DEBUG("The certificate is not trusted.\n"); | |
194 | ||
195 | if (status & GNUTLS_CERT_SIGNER_NOT_FOUND) | |
196 | VNC_DEBUG("The certificate hasn't got a known issuer.\n"); | |
197 | ||
198 | if (status & GNUTLS_CERT_REVOKED) | |
199 | VNC_DEBUG("The certificate has been revoked.\n"); | |
200 | ||
201 | if (status & GNUTLS_CERT_INSECURE_ALGORITHM) | |
202 | VNC_DEBUG("The certificate uses an insecure algorithm\n"); | |
203 | ||
204 | return -1; | |
205 | } else { | |
206 | VNC_DEBUG("Certificate is valid!\n"); | |
207 | } | |
208 | ||
209 | /* Only support x509 for now */ | |
210 | if (gnutls_certificate_type_get(vs->tls.session) != GNUTLS_CRT_X509) | |
211 | return -1; | |
212 | ||
213 | if (!(certs = gnutls_certificate_get_peers(vs->tls.session, &nCerts))) | |
214 | return -1; | |
215 | ||
216 | for (i = 0 ; i < nCerts ; i++) { | |
217 | gnutls_x509_crt_t cert; | |
218 | VNC_DEBUG ("Checking certificate chain %d\n", i); | |
219 | if (gnutls_x509_crt_init (&cert) < 0) | |
220 | return -1; | |
221 | ||
222 | if (gnutls_x509_crt_import(cert, &certs[i], GNUTLS_X509_FMT_DER) < 0) { | |
223 | gnutls_x509_crt_deinit (cert); | |
224 | return -1; | |
225 | } | |
226 | ||
227 | if (gnutls_x509_crt_get_expiration_time (cert) < now) { | |
228 | VNC_DEBUG("The certificate has expired\n"); | |
229 | gnutls_x509_crt_deinit (cert); | |
230 | return -1; | |
231 | } | |
232 | ||
233 | if (gnutls_x509_crt_get_activation_time (cert) > now) { | |
234 | VNC_DEBUG("The certificate is not yet activated\n"); | |
235 | gnutls_x509_crt_deinit (cert); | |
236 | return -1; | |
237 | } | |
238 | ||
239 | if (gnutls_x509_crt_get_activation_time (cert) > now) { | |
240 | VNC_DEBUG("The certificate is not yet activated\n"); | |
241 | gnutls_x509_crt_deinit (cert); | |
242 | return -1; | |
243 | } | |
244 | ||
245 | if (i == 0) { | |
246 | size_t dnameSize = 1024; | |
7267c094 | 247 | vs->tls.dname = g_malloc(dnameSize); |
274b6fcc AL |
248 | requery: |
249 | if ((ret = gnutls_x509_crt_get_dn (cert, vs->tls.dname, &dnameSize)) != 0) { | |
250 | if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER) { | |
7267c094 | 251 | vs->tls.dname = g_realloc(vs->tls.dname, dnameSize); |
274b6fcc AL |
252 | goto requery; |
253 | } | |
254 | gnutls_x509_crt_deinit (cert); | |
255 | VNC_DEBUG("Cannot get client distinguished name: %s", | |
256 | gnutls_strerror (ret)); | |
257 | return -1; | |
258 | } | |
259 | ||
260 | if (vs->vd->tls.x509verify) { | |
261 | int allow; | |
262 | if (!vs->vd->tls.acl) { | |
263 | VNC_DEBUG("no ACL activated, allowing access"); | |
264 | gnutls_x509_crt_deinit (cert); | |
265 | continue; | |
266 | } | |
267 | ||
268 | allow = qemu_acl_party_is_allowed(vs->vd->tls.acl, | |
269 | vs->tls.dname); | |
270 | ||
271 | VNC_DEBUG("TLS x509 ACL check for %s is %s\n", | |
272 | vs->tls.dname, allow ? "allowed" : "denied"); | |
273 | if (!allow) { | |
274 | gnutls_x509_crt_deinit (cert); | |
275 | return -1; | |
276 | } | |
277 | } | |
278 | } | |
279 | ||
280 | gnutls_x509_crt_deinit (cert); | |
281 | } | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
f40d5508 GH |
286 | #if defined(GNUTLS_VERSION_NUMBER) && \ |
287 | GNUTLS_VERSION_NUMBER >= 0x020200 /* 2.2.0 */ | |
288 | ||
289 | static int vnc_set_gnutls_priority(gnutls_session_t s, int x509) | |
290 | { | |
291 | const char *priority = x509 ? "NORMAL" : "NORMAL:+ANON-DH"; | |
292 | int rc; | |
293 | ||
294 | rc = gnutls_priority_set_direct(s, priority, NULL); | |
295 | if (rc != GNUTLS_E_SUCCESS) { | |
296 | return -1; | |
297 | } | |
298 | return 0; | |
299 | } | |
300 | ||
301 | #else | |
302 | ||
303 | static int vnc_set_gnutls_priority(gnutls_session_t s, int x509) | |
304 | { | |
305 | static const int cert_types[] = { GNUTLS_CRT_X509, 0 }; | |
306 | static const int protocols[] = { | |
307 | GNUTLS_TLS1_1, GNUTLS_TLS1_0, GNUTLS_SSL3, 0 | |
308 | }; | |
309 | static const int kx_anon[] = { GNUTLS_KX_ANON_DH, 0 }; | |
310 | static const int kx_x509[] = { | |
311 | GNUTLS_KX_DHE_DSS, GNUTLS_KX_RSA, | |
312 | GNUTLS_KX_DHE_RSA, GNUTLS_KX_SRP, 0 | |
313 | }; | |
314 | int rc; | |
315 | ||
316 | rc = gnutls_kx_set_priority(s, x509 ? kx_x509 : kx_anon); | |
317 | if (rc != GNUTLS_E_SUCCESS) { | |
318 | return -1; | |
319 | } | |
320 | ||
321 | rc = gnutls_certificate_type_set_priority(s, cert_types); | |
322 | if (rc != GNUTLS_E_SUCCESS) { | |
323 | return -1; | |
324 | } | |
325 | ||
326 | rc = gnutls_protocol_set_priority(s, protocols); | |
327 | if (rc != GNUTLS_E_SUCCESS) { | |
328 | return -1; | |
329 | } | |
330 | return 0; | |
331 | } | |
332 | ||
333 | #endif | |
274b6fcc AL |
334 | |
335 | int vnc_tls_client_setup(struct VncState *vs, | |
336 | int needX509Creds) { | |
274b6fcc AL |
337 | |
338 | VNC_DEBUG("Do TLS setup\n"); | |
339 | if (vnc_tls_initialize() < 0) { | |
340 | VNC_DEBUG("Failed to init TLS\n"); | |
341 | vnc_client_error(vs); | |
342 | return -1; | |
343 | } | |
344 | if (vs->tls.session == NULL) { | |
345 | if (gnutls_init(&vs->tls.session, GNUTLS_SERVER) < 0) { | |
346 | vnc_client_error(vs); | |
347 | return -1; | |
348 | } | |
349 | ||
350 | if (gnutls_set_default_priority(vs->tls.session) < 0) { | |
351 | gnutls_deinit(vs->tls.session); | |
352 | vs->tls.session = NULL; | |
353 | vnc_client_error(vs); | |
354 | return -1; | |
355 | } | |
356 | ||
f40d5508 | 357 | if (vnc_set_gnutls_priority(vs->tls.session, needX509Creds) < 0) { |
274b6fcc AL |
358 | gnutls_deinit(vs->tls.session); |
359 | vs->tls.session = NULL; | |
360 | vnc_client_error(vs); | |
361 | return -1; | |
362 | } | |
363 | ||
364 | if (needX509Creds) { | |
365 | gnutls_certificate_server_credentials x509_cred = vnc_tls_initialize_x509_cred(vs->vd); | |
366 | if (!x509_cred) { | |
367 | gnutls_deinit(vs->tls.session); | |
368 | vs->tls.session = NULL; | |
369 | vnc_client_error(vs); | |
370 | return -1; | |
371 | } | |
372 | if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_CERTIFICATE, x509_cred) < 0) { | |
373 | gnutls_deinit(vs->tls.session); | |
374 | vs->tls.session = NULL; | |
375 | gnutls_certificate_free_credentials(x509_cred); | |
376 | vnc_client_error(vs); | |
377 | return -1; | |
378 | } | |
379 | if (vs->vd->tls.x509verify) { | |
380 | VNC_DEBUG("Requesting a client certificate\n"); | |
381 | gnutls_certificate_server_set_request (vs->tls.session, GNUTLS_CERT_REQUEST); | |
382 | } | |
383 | ||
384 | } else { | |
385 | gnutls_anon_server_credentials anon_cred = vnc_tls_initialize_anon_cred(); | |
386 | if (!anon_cred) { | |
387 | gnutls_deinit(vs->tls.session); | |
388 | vs->tls.session = NULL; | |
389 | vnc_client_error(vs); | |
390 | return -1; | |
391 | } | |
392 | if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_ANON, anon_cred) < 0) { | |
393 | gnutls_deinit(vs->tls.session); | |
394 | vs->tls.session = NULL; | |
395 | gnutls_anon_free_server_credentials(anon_cred); | |
396 | vnc_client_error(vs); | |
397 | return -1; | |
398 | } | |
399 | } | |
400 | ||
401 | gnutls_transport_set_ptr(vs->tls.session, (gnutls_transport_ptr_t)vs); | |
402 | gnutls_transport_set_push_function(vs->tls.session, vnc_tls_push); | |
403 | gnutls_transport_set_pull_function(vs->tls.session, vnc_tls_pull); | |
404 | } | |
405 | return 0; | |
406 | } | |
407 | ||
408 | ||
409 | void vnc_tls_client_cleanup(struct VncState *vs) | |
410 | { | |
411 | if (vs->tls.session) { | |
412 | gnutls_deinit(vs->tls.session); | |
413 | vs->tls.session = NULL; | |
414 | } | |
415 | vs->tls.wiremode = VNC_WIREMODE_CLEAR; | |
ae878b17 | 416 | g_free(vs->tls.dname); |
274b6fcc AL |
417 | } |
418 | ||
419 | ||
420 | ||
421 | static int vnc_set_x509_credential(VncDisplay *vd, | |
422 | const char *certdir, | |
423 | const char *filename, | |
424 | char **cred, | |
425 | int ignoreMissing) | |
426 | { | |
427 | struct stat sb; | |
428 | ||
429 | if (*cred) { | |
7267c094 | 430 | g_free(*cred); |
274b6fcc AL |
431 | *cred = NULL; |
432 | } | |
433 | ||
7267c094 | 434 | *cred = g_malloc(strlen(certdir) + strlen(filename) + 2); |
274b6fcc AL |
435 | |
436 | strcpy(*cred, certdir); | |
437 | strcat(*cred, "/"); | |
438 | strcat(*cred, filename); | |
439 | ||
440 | VNC_DEBUG("Check %s\n", *cred); | |
441 | if (stat(*cred, &sb) < 0) { | |
7267c094 | 442 | g_free(*cred); |
274b6fcc AL |
443 | *cred = NULL; |
444 | if (ignoreMissing && errno == ENOENT) | |
445 | return 0; | |
446 | return -1; | |
447 | } | |
448 | ||
449 | return 0; | |
450 | } | |
451 | ||
452 | ||
274b6fcc AL |
453 | int vnc_tls_set_x509_creds_dir(VncDisplay *vd, |
454 | const char *certdir) | |
455 | { | |
456 | if (vnc_set_x509_credential(vd, certdir, X509_CA_CERT_FILE, &vd->tls.x509cacert, 0) < 0) | |
457 | goto cleanup; | |
458 | if (vnc_set_x509_credential(vd, certdir, X509_CA_CRL_FILE, &vd->tls.x509cacrl, 1) < 0) | |
459 | goto cleanup; | |
460 | if (vnc_set_x509_credential(vd, certdir, X509_SERVER_CERT_FILE, &vd->tls.x509cert, 0) < 0) | |
461 | goto cleanup; | |
462 | if (vnc_set_x509_credential(vd, certdir, X509_SERVER_KEY_FILE, &vd->tls.x509key, 0) < 0) | |
463 | goto cleanup; | |
464 | ||
465 | return 0; | |
466 | ||
467 | cleanup: | |
7267c094 AL |
468 | g_free(vd->tls.x509cacert); |
469 | g_free(vd->tls.x509cacrl); | |
470 | g_free(vd->tls.x509cert); | |
471 | g_free(vd->tls.x509key); | |
274b6fcc AL |
472 | vd->tls.x509cacert = vd->tls.x509cacrl = vd->tls.x509cert = vd->tls.x509key = NULL; |
473 | return -1; | |
474 | } | |
475 |