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
32static int
33lookup_key(const char *pskfile, const char *username, gnutls_datum_t *key,
34 Error **errp)
35{
36 const size_t ulen = strlen(username);
37 GError *gerr = NULL;
38 char *content = NULL;
39 char **lines = NULL;
40 size_t clen = 0, i;
41 int ret = -1;
42
43 if (!g_file_get_contents(pskfile, &content, &clen, &gerr)) {
44 error_setg(errp, "Cannot read PSK file %s: %s",
45 pskfile, gerr->message);
46 g_error_free(gerr);
47 return -1;
48 }
49
50 lines = g_strsplit(content, "\n", -1);
51 for (i = 0; lines[i] != NULL; ++i) {
52 if (strncmp(lines[i], username, ulen) == 0 && lines[i][ulen] == ':') {
53 key->data = (unsigned char *) g_strdup(&lines[i][ulen + 1]);
54 key->size = strlen(lines[i]) - ulen - 1;
55 ret = 0;
56 goto out;
57 }
58 }
59 error_setg(errp, "Username %s not found in PSK file %s",
60 username, pskfile);
61
62 out:
63 free(content);
64 g_strfreev(lines);
65 return ret;
66}
67
68static int
69qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds,
70 Error **errp)
71{
72 g_autofree char *pskfile = NULL;
73 g_autofree char *dhparams = NULL;
74 const char *username;
75 int ret;
76 int rv = -1;
77 gnutls_datum_t key = { .data = NULL };
78
79 trace_qcrypto_tls_creds_psk_load(creds,
80 creds->parent_obj.dir ? creds->parent_obj.dir : "<nodir>");
81
82 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
83 if (creds->username) {
84 error_setg(errp, "username should not be set when endpoint=server");
85 goto cleanup;
86 }
87
88 if (qcrypto_tls_creds_get_path(&creds->parent_obj,
89 QCRYPTO_TLS_CREDS_DH_PARAMS,
90 false, &dhparams, errp) < 0 ||
91 qcrypto_tls_creds_get_path(&creds->parent_obj,
92 QCRYPTO_TLS_CREDS_PSKFILE,
93 true, &pskfile, errp) < 0) {
94 goto cleanup;
95 }
96
97 ret = gnutls_psk_allocate_server_credentials(&creds->data.server);
98 if (ret < 0) {
99 error_setg(errp, "Cannot allocate credentials: %s",
100 gnutls_strerror(ret));
101 goto cleanup;
102 }
103
104 if (qcrypto_tls_creds_get_dh_params_file(&creds->parent_obj, dhparams,
105 &creds->parent_obj.dh_params,
106 errp) < 0) {
107 goto cleanup;
108 }
109
110 gnutls_psk_set_server_credentials_file(creds->data.server, pskfile);
111 gnutls_psk_set_server_dh_params(creds->data.server,
112 creds->parent_obj.dh_params);
113 } else {
114 if (qcrypto_tls_creds_get_path(&creds->parent_obj,
115 QCRYPTO_TLS_CREDS_PSKFILE,
116 true, &pskfile, errp) < 0) {
117 goto cleanup;
118 }
119
120 if (creds->username) {
121 username = creds->username;
122 } else {
123 username = "qemu";
124 }
125 if (lookup_key(pskfile, username, &key, errp) != 0) {
126 goto cleanup;
127 }
128
129 ret = gnutls_psk_allocate_client_credentials(&creds->data.client);
130 if (ret < 0) {
131 error_setg(errp, "Cannot allocate credentials: %s",
132 gnutls_strerror(ret));
133 goto cleanup;
134 }
135
136 gnutls_psk_set_client_credentials(creds->data.client,
137 username, &key, GNUTLS_PSK_KEY_HEX);
138 }
139
140 rv = 0;
141 cleanup:
142 g_free(key.data);
143 return rv;
144}
145
146
147static void
148qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds)
149{
150 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) {
151 if (creds->data.client) {
152 gnutls_psk_free_client_credentials(creds->data.client);
153 creds->data.client = NULL;
154 }
155 } else {
156 if (creds->data.server) {
157 gnutls_psk_free_server_credentials(creds->data.server);
158 creds->data.server = NULL;
159 }
160 }
161 if (creds->parent_obj.dh_params) {
162 gnutls_dh_params_deinit(creds->parent_obj.dh_params);
163 creds->parent_obj.dh_params = NULL;
164 }
165}
166
167#else /* ! CONFIG_GNUTLS */
168
169
170static void
171qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED,
172 Error **errp)
173{
174 error_setg(errp, "TLS credentials support requires GNUTLS");
175}
176
177
178static void
179qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED)
180{
181 /* nada */
182}
183
184
185#endif /* ! CONFIG_GNUTLS */
186
187
188static void
189qcrypto_tls_creds_psk_prop_set_loaded(Object *obj,
190 bool value,
191 Error **errp)
192{
193 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
194
195 if (value) {
196 qcrypto_tls_creds_psk_load(creds, errp);
197 } else {
198 qcrypto_tls_creds_psk_unload(creds);
199 }
200}
201
202
203#ifdef CONFIG_GNUTLS
204
205
206static bool
207qcrypto_tls_creds_psk_prop_get_loaded(Object *obj,
208 Error **errp G_GNUC_UNUSED)
209{
210 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
211
212 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
213 return creds->data.server != NULL;
214 } else {
215 return creds->data.client != NULL;
216 }
217}
218
219
220#else /* ! CONFIG_GNUTLS */
221
222
223static bool
224qcrypto_tls_creds_psk_prop_get_loaded(Object *obj G_GNUC_UNUSED,
225 Error **errp G_GNUC_UNUSED)
226{
227 return false;
228}
229
230
231#endif /* ! CONFIG_GNUTLS */
232
233
234static void
235qcrypto_tls_creds_psk_complete(UserCreatable *uc, Error **errp)
236{
237 object_property_set_bool(OBJECT(uc), true, "loaded", errp);
238}
239
240
241static void
242qcrypto_tls_creds_psk_finalize(Object *obj)
243{
244 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj);
245
246 qcrypto_tls_creds_psk_unload(creds);
247}
248
249static void
250qcrypto_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
260static char *
261qcrypto_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
269static void
270qcrypto_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 qcrypto_tls_creds_psk_prop_set_loaded,
279 NULL);
280 object_class_property_add_str(oc, "username",
281 qcrypto_tls_creds_psk_prop_get_username,
282 qcrypto_tls_creds_psk_prop_set_username,
283 NULL);
284}
285
286
287static const TypeInfo qcrypto_tls_creds_psk_info = {
288 .parent = TYPE_QCRYPTO_TLS_CREDS,
289 .name = TYPE_QCRYPTO_TLS_CREDS_PSK,
290 .instance_size = sizeof(QCryptoTLSCredsPSK),
291 .instance_finalize = qcrypto_tls_creds_psk_finalize,
292 .class_size = sizeof(QCryptoTLSCredsPSKClass),
293 .class_init = qcrypto_tls_creds_psk_class_init,
294 .interfaces = (InterfaceInfo[]) {
295 { TYPE_USER_CREATABLE },
296 { }
297 }
298};
299
300
301static void
302qcrypto_tls_creds_psk_register_types(void)
303{
304 type_register_static(&qcrypto_tls_creds_psk_info);
305}
306
307
308type_init(qcrypto_tls_creds_psk_register_types);
309