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 static int 33 lookup_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 68 static int 69 qcrypto_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 } 145 146 147 static void 148 qcrypto_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 */ 168 169 170 static void 171 qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED, 172 Error **errp) 173 { 174 error_setg(errp, "TLS credentials support requires GNUTLS"); 175 } 176 177 178 static void 179 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED) 180 { 181 /* nada */ 182 } 183 184 185 #endif /* ! CONFIG_GNUTLS */ 186 187 188 static void 189 qcrypto_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 204 205 206 static bool 207 qcrypto_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 */ 221 222 223 static bool 224 qcrypto_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 */ 232 233 234 static void 235 qcrypto_tls_creds_psk_complete(UserCreatable *uc, Error **errp) 236 { 237 object_property_set_bool(OBJECT(uc), true, "loaded", errp); 238 } 239 240 241 static void 242 qcrypto_tls_creds_psk_finalize(Object *obj) 243 { 244 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 245 246 qcrypto_tls_creds_psk_unload(creds); 247 } 248 249 static void 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 * 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 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 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 } 285 286 287 static 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 }; 299 300 301 static void 302 qcrypto_tls_creds_psk_register_types(void) 303 { 304 type_register_static(&qcrypto_tls_creds_psk_info); 305 } 306 307 308 type_init(qcrypto_tls_creds_psk_register_types); 309