1 /*
2 * QEMU crypto TLS Pre-Shared Keys (PSK) support
3 *
4 * Copyright (c) 2018 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "crypto/tlscredspsk.h"
23 #include "tlscredspriv.h"
24 #include "qapi/error.h"
25 #include "qemu/module.h"
26 #include "qom/object_interfaces.h"
27 #include "trace.h"
28
29
30 #ifdef CONFIG_GNUTLS
31
32 #include <gnutls/gnutls.h>
33
34 static int
lookup_key(const char * pskfile,const char * username,gnutls_datum_t * key,Error ** errp)35 lookup_key(const char *pskfile, const char *username, gnutls_datum_t *key,
36 Error **errp)
37 {
38 const size_t ulen = strlen(username);
39 GError *gerr = NULL;
40 char *content = NULL;
41 char **lines = NULL;
42 size_t clen = 0, i;
43 int ret = -1;
44
45 if (!g_file_get_contents(pskfile, &content, &clen, &gerr)) {
46 error_setg(errp, "Cannot read PSK file %s: %s",
47 pskfile, gerr->message);
48 g_error_free(gerr);
49 return -1;
50 }
51
52 lines = g_strsplit(content, "\n", -1);
53 for (i = 0; lines[i] != NULL; ++i) {
54 if (strncmp(lines[i], username, ulen) == 0 && lines[i][ulen] == ':') {
55 key->data = (unsigned char *) g_strdup(&lines[i][ulen + 1]);
56 key->size = strlen(lines[i]) - ulen - 1;
57 ret = 0;
58 goto out;
59 }
60 }
61 error_setg(errp, "Username %s not found in PSK file %s",
62 username, pskfile);
63
64 out:
65 free(content);
66 g_strfreev(lines);
67 return ret;
68 }
69
70 static int
qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK * creds,Error ** errp)71 qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds,
72 Error **errp)
73 {
74 g_autofree char *pskfile = NULL;
75 g_autofree char *dhparams = NULL;
76 const char *username;
77 int ret;
78 int rv = -1;
79 gnutls_datum_t key = { .data = NULL };
80
81 trace_qcrypto_tls_creds_psk_load(creds,
82 creds->parent_obj.dir ? creds->parent_obj.dir : "<nodir>");
83
84 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
85 if (creds->username) {
86 error_setg(errp, "username should not be set when endpoint=server");
87 goto cleanup;
88 }
89
90 if (qcrypto_tls_creds_get_path(&creds->parent_obj,
91 QCRYPTO_TLS_CREDS_DH_PARAMS,
92 false, &dhparams, errp) < 0 ||
93 qcrypto_tls_creds_get_path(&creds->parent_obj,
94 QCRYPTO_TLS_CREDS_PSKFILE,
95 true, &pskfile, errp) < 0) {
96 goto cleanup;
97 }
98
99 ret = gnutls_psk_allocate_server_credentials(&creds->data.server);
100 if (ret < 0) {
101 error_setg(errp, "Cannot allocate credentials: %s",
102 gnutls_strerror(ret));
103 goto cleanup;
104 }
105
106 if (qcrypto_tls_creds_get_dh_params_file(&creds->parent_obj, dhparams,
107 &creds->parent_obj.dh_params,
108 errp) < 0) {
109 goto cleanup;
110 }
111
112 ret = gnutls_psk_set_server_credentials_file(creds->data.server, pskfile);
113 if (ret < 0) {
114 error_setg(errp, "Cannot set PSK server credentials: %s",
115 gnutls_strerror(ret));
116 goto cleanup;
117 }
118 gnutls_psk_set_server_dh_params(creds->data.server,
119 creds->parent_obj.dh_params);
120 } else {
121 if (qcrypto_tls_creds_get_path(&creds->parent_obj,
122 QCRYPTO_TLS_CREDS_PSKFILE,
123 true, &pskfile, errp) < 0) {
124 goto cleanup;
125 }
126
127 if (creds->username) {
128 username = creds->username;
129 } else {
130 username = "qemu";
131 }
132 if (lookup_key(pskfile, username, &key, errp) != 0) {
133 goto cleanup;
134 }
135
136 ret = gnutls_psk_allocate_client_credentials(&creds->data.client);
137 if (ret < 0) {
138 error_setg(errp, "Cannot allocate credentials: %s",
139 gnutls_strerror(ret));
140 goto cleanup;
141 }
142
143 ret = gnutls_psk_set_client_credentials(creds->data.client,
144 username, &key, GNUTLS_PSK_KEY_HEX);
145 if (ret < 0) {
146 error_setg(errp, "Cannot set PSK client credentials: %s",
147 gnutls_strerror(ret));
148 goto cleanup;
149 }
150 }
151
152 rv = 0;
153 cleanup:
154 g_free(key.data);
155 return rv;
156 }
157
158
159 static void
qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK * creds)160 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds)
161 {
162 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
163 if (creds->data.client) {
164 gnutls_psk_free_client_credentials(creds->data.client);
165 creds->data.client = NULL;
166 }
167 } else {
168 if (creds->data.server) {
169 gnutls_psk_free_server_credentials(creds->data.server);
170 creds->data.server = NULL;
171 }
172 }
173 if (creds->parent_obj.dh_params) {
174 gnutls_dh_params_deinit(creds->parent_obj.dh_params);
175 creds->parent_obj.dh_params = NULL;
176 }
177 }
178
179 #else /* ! CONFIG_GNUTLS */
180
181
182 static void
qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK * creds G_GNUC_UNUSED,Error ** errp)183 qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED,
184 Error **errp)
185 {
186 error_setg(errp, "TLS credentials support requires GNUTLS");
187 }
188
189
190 static void
qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK * creds G_GNUC_UNUSED)191 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED)
192 {
193 /* nada */
194 }
195
196
197 #endif /* ! CONFIG_GNUTLS */
198
199
200 static void
qcrypto_tls_creds_psk_complete(UserCreatable * uc,Error ** errp)201 qcrypto_tls_creds_psk_complete(UserCreatable *uc, Error **errp)
202 {
203 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(uc);
204
205 qcrypto_tls_creds_psk_load(creds, errp);
206 }
207
208
209 #ifdef CONFIG_GNUTLS
210
211
212 static bool
qcrypto_tls_creds_psk_prop_get_loaded(Object * obj,Error ** errp G_GNUC_UNUSED)213 qcrypto_tls_creds_psk_prop_get_loaded(Object *obj,
214 Error **errp G_GNUC_UNUSED)
215 {
216 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
217
218 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
219 return creds->data.server != NULL;
220 } else {
221 return creds->data.client != NULL;
222 }
223 }
224
225
226 #else /* ! CONFIG_GNUTLS */
227
228
229 static bool
qcrypto_tls_creds_psk_prop_get_loaded(Object * obj G_GNUC_UNUSED,Error ** errp G_GNUC_UNUSED)230 qcrypto_tls_creds_psk_prop_get_loaded(Object *obj G_GNUC_UNUSED,
231 Error **errp G_GNUC_UNUSED)
232 {
233 return false;
234 }
235
236
237 #endif /* ! CONFIG_GNUTLS */
238
239
240 static void
qcrypto_tls_creds_psk_finalize(Object * obj)241 qcrypto_tls_creds_psk_finalize(Object *obj)
242 {
243 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
244
245 qcrypto_tls_creds_psk_unload(creds);
246 g_free(creds->username);
247 }
248
249 static void
qcrypto_tls_creds_psk_prop_set_username(Object * obj,const char * value,Error ** errp G_GNUC_UNUSED)250 qcrypto_tls_creds_psk_prop_set_username(Object *obj,
251 const char *value,
252 Error **errp G_GNUC_UNUSED)
253 {
254 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
255
256 creds->username = g_strdup(value);
257 }
258
259
260 static char *
qcrypto_tls_creds_psk_prop_get_username(Object * obj,Error ** errp G_GNUC_UNUSED)261 qcrypto_tls_creds_psk_prop_get_username(Object *obj,
262 Error **errp G_GNUC_UNUSED)
263 {
264 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
265
266 return g_strdup(creds->username);
267 }
268
269 static void
qcrypto_tls_creds_psk_class_init(ObjectClass * oc,void * data)270 qcrypto_tls_creds_psk_class_init(ObjectClass *oc, void *data)
271 {
272 UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
273
274 ucc->complete = qcrypto_tls_creds_psk_complete;
275
276 object_class_property_add_bool(oc, "loaded",
277 qcrypto_tls_creds_psk_prop_get_loaded,
278 NULL);
279 object_class_property_add_str(oc, "username",
280 qcrypto_tls_creds_psk_prop_get_username,
281 qcrypto_tls_creds_psk_prop_set_username);
282 }
283
284
285 static const TypeInfo qcrypto_tls_creds_psk_info = {
286 .parent = TYPE_QCRYPTO_TLS_CREDS,
287 .name = TYPE_QCRYPTO_TLS_CREDS_PSK,
288 .instance_size = sizeof(QCryptoTLSCredsPSK),
289 .instance_finalize = qcrypto_tls_creds_psk_finalize,
290 .class_size = sizeof(QCryptoTLSCredsPSKClass),
291 .class_init = qcrypto_tls_creds_psk_class_init,
292 .interfaces = (InterfaceInfo[]) {
293 { TYPE_USER_CREATABLE },
294 { }
295 }
296 };
297
298
299 static void
qcrypto_tls_creds_psk_register_types(void)300 qcrypto_tls_creds_psk_register_types(void)
301 {
302 type_register_static(&qcrypto_tls_creds_psk_info);
303 }
304
305
306 type_init(qcrypto_tls_creds_psk_register_types);
307