Bug Summary

File:ui/vnc-tls.c
Location:line 136, column 10
Description:Although the value stored to 'ret' is used in the enclosing expression, the value is never actually read from 'ret'

Annotated Source Code

1/*
2 * QEMU VNC display driver: TLS helpers
3 *
4 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
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
27#include "qemu-x509.h"
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 */
33static void vnc_debug_gnutls_log(int level, const char* str) {
34 VNC_DEBUG("%d %s", level, str)do { } while (0);
35}
36#endif /* defined(_VNC_DEBUG) && _VNC_DEBUG >= 2 */
37
38
39#define DH_BITS1024 1024
40static gnutls_dh_params_t dh_params;
41
42static 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
52 /* XXX ought to re-generate diffie-hellmen params periodically */
53 if (gnutls_dh_params_init (&dh_params) < 0)
54 return 0;
55 if (gnutls_dh_params_generate2 (dh_params, DH_BITS1024) < 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
68static 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(*__errno_location ()) == EINTR4)
78 goto retry;
79 return -1;
80 }
81 return ret;
82}
83
84
85static 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:
92 ret = qemu_recv(vs->csock, data, len, 0)recv(vs->csock, data, len, 0);
93 if (ret < 0) {
94 if (errno(*__errno_location ()) == EINTR4)
95 goto retry;
96 return -1;
97 }
98 return ret;
99}
100
101
102static gnutls_anon_server_credentialsgnutls_anon_server_credentials_t vnc_tls_initialize_anon_cred(void)
103{
104 gnutls_anon_server_credentialsgnutls_anon_server_credentials_t 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))do { } while (0);
109 return NULL((void*)0);
110 }
111
112 gnutls_anon_set_server_dh_params(anon_cred, dh_params);
113
114 return anon_cred;
115}
116
117
118static 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")do { } while (0);
125 return NULL((void*)0);
126 }
127 if (!vd->tls.x509cert) {
128 VNC_DEBUG("No server x509 certificate specified\n")do { } while (0);
129 return NULL((void*)0);
130 }
131 if (!vd->tls.x509key) {
132 VNC_DEBUG("No server private key specified\n")do { } while (0);
133 return NULL((void*)0);
134 }
135
136 if ((ret = gnutls_certificate_allocate_credentials(&x509_cred)) < 0) {
Although the value stored to 'ret' is used in the enclosing expression, the value is never actually read from 'ret'
137 VNC_DEBUG("Cannot allocate credentials %s\n", gnutls_strerror(ret))do { } while (0);
138 return NULL((void*)0);
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))do { } while (0);
144 gnutls_certificate_free_credentials(x509_cred);
145 return NULL((void*)0);
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))do { } while (0);
153 gnutls_certificate_free_credentials(x509_cred);
154 return NULL((void*)0);
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))do { } while (0);
162 gnutls_certificate_free_credentials(x509_cred);
163 return NULL((void*)0);
164 }
165 }
166
167 gnutls_certificate_set_dh_params (x509_cred, dh_params);
168
169 return x509_cred;
170}
171
172
173int 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")do { } while (0);
182 if ((ret = gnutls_certificate_verify_peers2 (vs->tls.session, &status)) < 0) {
183 VNC_DEBUG("Verify failed %s\n", gnutls_strerror(ret))do { } while (0);
184 return -1;
185 }
186
187 if ((now = time(NULL((void*)0))) == ((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")do { } while (0);
194
195 if (status & GNUTLS_CERT_SIGNER_NOT_FOUND)
196 VNC_DEBUG("The certificate hasn't got a known issuer.\n")do { } while (0);
197
198 if (status & GNUTLS_CERT_REVOKED)
199 VNC_DEBUG("The certificate has been revoked.\n")do { } while (0);
200
201 if (status & GNUTLS_CERT_INSECURE_ALGORITHM)
202 VNC_DEBUG("The certificate uses an insecure algorithm\n")do { } while (0);
203
204 return -1;
205 } else {
206 VNC_DEBUG("Certificate is valid!\n")do { } while (0);
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)do { } while (0);
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")do { } while (0);
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")do { } while (0);
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")do { } while (0);
241 gnutls_x509_crt_deinit (cert);
242 return -1;
243 }
244
245 if (i == 0) {
246 size_t dnameSize = 1024;
247 vs->tls.dname = g_malloc(dnameSize);
248 requery:
249 if ((ret = gnutls_x509_crt_get_dn (cert, vs->tls.dname, &dnameSize)) != 0) {
250 if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER-51) {
251 vs->tls.dname = g_realloc(vs->tls.dname, dnameSize);
252 goto requery;
253 }
254 gnutls_x509_crt_deinit (cert);
255 VNC_DEBUG("Cannot get client distinguished name: %s",do { } while (0)
256 gnutls_strerror (ret))do { } while (0);
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")do { } while (0);
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",do { } while (0)
272 vs->tls.dname, allow ? "allowed" : "denied")do { } while (0);
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
286#if defined(GNUTLS_VERSION_NUMBER0x020806) && \
287 GNUTLS_VERSION_NUMBER0x020806 >= 0x020200 /* 2.2.0 */
288
289static 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((void*)0));
295 if (rc != GNUTLS_E_SUCCESS0) {
296 return -1;
297 }
298 return 0;
299}
300
301#else
302
303static 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_SUCCESS0) {
318 return -1;
319 }
320
321 rc = gnutls_certificate_type_set_priority(s, cert_types);
322 if (rc != GNUTLS_E_SUCCESS0) {
323 return -1;
324 }
325
326 rc = gnutls_protocol_set_priority(s, protocols);
327 if (rc != GNUTLS_E_SUCCESS0) {
328 return -1;
329 }
330 return 0;
331}
332
333#endif
334
335int vnc_tls_client_setup(struct VncState *vs,
336 int needX509Creds) {
337
338 VNC_DEBUG("Do TLS setup\n")do { } while (0);
339 if (vnc_tls_initialize() < 0) {
340 VNC_DEBUG("Failed to init TLS\n")do { } while (0);
341 vnc_client_error(vs);
342 return -1;
343 }
344 if (vs->tls.session == NULL((void*)0)) {
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((void*)0);
353 vnc_client_error(vs);
354 return -1;
355 }
356
357 if (vnc_set_gnutls_priority(vs->tls.session, needX509Creds) < 0) {
358 gnutls_deinit(vs->tls.session);
359 vs->tls.session = NULL((void*)0);
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((void*)0);
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((void*)0);
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")do { } while (0);
381 gnutls_certificate_server_set_request (vs->tls.session, GNUTLS_CERT_REQUEST);
382 }
383
384 } else {
385 gnutls_anon_server_credentialsgnutls_anon_server_credentials_t anon_cred = vnc_tls_initialize_anon_cred();
386 if (!anon_cred) {
387 gnutls_deinit(vs->tls.session);
388 vs->tls.session = NULL((void*)0);
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((void*)0);
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
409void vnc_tls_client_cleanup(struct VncState *vs)
410{
411 if (vs->tls.session) {
412 gnutls_deinit(vs->tls.session);
413 vs->tls.session = NULL((void*)0);
414 }
415 vs->tls.wiremode = VNC_WIREMODE_CLEAR;
416 g_free(vs->tls.dname);
417}
418
419
420
421static 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) {
430 g_free(*cred);
431 *cred = NULL((void*)0);
432 }
433
434 *cred = g_malloc(strlen(certdir) + strlen(filename) + 2);
435
436 strcpy(*cred, certdir);
437 strcat(*cred, "/");
438 strcat(*cred, filename);
439
440 VNC_DEBUG("Check %s\n", *cred)do { } while (0);
441 if (stat(*cred, &sb) < 0) {
442 g_free(*cred);
443 *cred = NULL((void*)0);
444 if (ignoreMissing && errno(*__errno_location ()) == ENOENT2)
445 return 0;
446 return -1;
447 }
448
449 return 0;
450}
451
452
453int 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"ca-cert.pem", &vd->tls.x509cacert, 0) < 0)
457 goto cleanup;
458 if (vnc_set_x509_credential(vd, certdir, X509_CA_CRL_FILE"ca-crl.pem", &vd->tls.x509cacrl, 1) < 0)
459 goto cleanup;
460 if (vnc_set_x509_credential(vd, certdir, X509_SERVER_CERT_FILE"server-cert.pem", &vd->tls.x509cert, 0) < 0)
461 goto cleanup;
462 if (vnc_set_x509_credential(vd, certdir, X509_SERVER_KEY_FILE"server-key.pem", &vd->tls.x509key, 0) < 0)
463 goto cleanup;
464
465 return 0;
466
467 cleanup:
468 g_free(vd->tls.x509cacert);
469 g_free(vd->tls.x509cacrl);
470 g_free(vd->tls.x509cert);
471 g_free(vd->tls.x509key);
472 vd->tls.x509cacert = vd->tls.x509cacrl = vd->tls.x509cert = vd->tls.x509key = NULL((void*)0);
473 return -1;
474}
475