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 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 char *pskfile = NULL, *dhparams = NULL; 73 const char *username; 74 int ret; 75 int rv = -1; 76 gnutls_datum_t key = { .data = NULL }; 77 78 trace_qcrypto_tls_creds_psk_load(creds, 79 creds->parent_obj.dir ? creds->parent_obj.dir : "<nodir>"); 80 81 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { 82 if (creds->username) { 83 error_setg(errp, "username should not be set when endpoint=server"); 84 goto cleanup; 85 } 86 87 if (qcrypto_tls_creds_get_path(&creds->parent_obj, 88 QCRYPTO_TLS_CREDS_DH_PARAMS, 89 false, &dhparams, errp) < 0 || 90 qcrypto_tls_creds_get_path(&creds->parent_obj, 91 QCRYPTO_TLS_CREDS_PSKFILE, 92 true, &pskfile, errp) < 0) { 93 goto cleanup; 94 } 95 96 ret = gnutls_psk_allocate_server_credentials(&creds->data.server); 97 if (ret < 0) { 98 error_setg(errp, "Cannot allocate credentials: %s", 99 gnutls_strerror(ret)); 100 goto cleanup; 101 } 102 103 if (qcrypto_tls_creds_get_dh_params_file(&creds->parent_obj, dhparams, 104 &creds->parent_obj.dh_params, 105 errp) < 0) { 106 goto cleanup; 107 } 108 109 gnutls_psk_set_server_credentials_file(creds->data.server, pskfile); 110 gnutls_psk_set_server_dh_params(creds->data.server, 111 creds->parent_obj.dh_params); 112 } else { 113 if (qcrypto_tls_creds_get_path(&creds->parent_obj, 114 QCRYPTO_TLS_CREDS_PSKFILE, 115 true, &pskfile, errp) < 0) { 116 goto cleanup; 117 } 118 119 if (creds->username) { 120 username = creds->username; 121 } else { 122 username = "qemu"; 123 } 124 if (lookup_key(pskfile, username, &key, errp) != 0) { 125 goto cleanup; 126 } 127 128 ret = gnutls_psk_allocate_client_credentials(&creds->data.client); 129 if (ret < 0) { 130 error_setg(errp, "Cannot allocate credentials: %s", 131 gnutls_strerror(ret)); 132 goto cleanup; 133 } 134 135 gnutls_psk_set_client_credentials(creds->data.client, 136 username, &key, GNUTLS_PSK_KEY_HEX); 137 } 138 139 rv = 0; 140 cleanup: 141 g_free(key.data); 142 g_free(pskfile); 143 g_free(dhparams); 144 return rv; 145 } 146 147 148 static void 149 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds) 150 { 151 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) { 152 if (creds->data.client) { 153 gnutls_psk_free_client_credentials(creds->data.client); 154 creds->data.client = NULL; 155 } 156 } else { 157 if (creds->data.server) { 158 gnutls_psk_free_server_credentials(creds->data.server); 159 creds->data.server = NULL; 160 } 161 } 162 if (creds->parent_obj.dh_params) { 163 gnutls_dh_params_deinit(creds->parent_obj.dh_params); 164 creds->parent_obj.dh_params = NULL; 165 } 166 } 167 168 #else /* ! CONFIG_GNUTLS */ 169 170 171 static void 172 qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED, 173 Error **errp) 174 { 175 error_setg(errp, "TLS credentials support requires GNUTLS"); 176 } 177 178 179 static void 180 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED) 181 { 182 /* nada */ 183 } 184 185 186 #endif /* ! CONFIG_GNUTLS */ 187 188 189 static void 190 qcrypto_tls_creds_psk_prop_set_loaded(Object *obj, 191 bool value, 192 Error **errp) 193 { 194 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 195 196 if (value) { 197 qcrypto_tls_creds_psk_load(creds, errp); 198 } else { 199 qcrypto_tls_creds_psk_unload(creds); 200 } 201 } 202 203 204 #ifdef CONFIG_GNUTLS 205 206 207 static bool 208 qcrypto_tls_creds_psk_prop_get_loaded(Object *obj, 209 Error **errp G_GNUC_UNUSED) 210 { 211 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 212 213 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) { 214 return creds->data.server != NULL; 215 } else { 216 return creds->data.client != NULL; 217 } 218 } 219 220 221 #else /* ! CONFIG_GNUTLS */ 222 223 224 static bool 225 qcrypto_tls_creds_psk_prop_get_loaded(Object *obj G_GNUC_UNUSED, 226 Error **errp G_GNUC_UNUSED) 227 { 228 return false; 229 } 230 231 232 #endif /* ! CONFIG_GNUTLS */ 233 234 235 static void 236 qcrypto_tls_creds_psk_complete(UserCreatable *uc, Error **errp) 237 { 238 object_property_set_bool(OBJECT(uc), true, "loaded", errp); 239 } 240 241 242 static void 243 qcrypto_tls_creds_psk_finalize(Object *obj) 244 { 245 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 246 247 qcrypto_tls_creds_psk_unload(creds); 248 } 249 250 static void 251 qcrypto_tls_creds_psk_prop_set_username(Object *obj, 252 const char *value, 253 Error **errp G_GNUC_UNUSED) 254 { 255 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 256 257 creds->username = g_strdup(value); 258 } 259 260 261 static char * 262 qcrypto_tls_creds_psk_prop_get_username(Object *obj, 263 Error **errp G_GNUC_UNUSED) 264 { 265 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 266 267 return g_strdup(creds->username); 268 } 269 270 static void 271 qcrypto_tls_creds_psk_class_init(ObjectClass *oc, void *data) 272 { 273 UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); 274 275 ucc->complete = qcrypto_tls_creds_psk_complete; 276 277 object_class_property_add_bool(oc, "loaded", 278 qcrypto_tls_creds_psk_prop_get_loaded, 279 qcrypto_tls_creds_psk_prop_set_loaded, 280 NULL); 281 object_class_property_add_str(oc, "username", 282 qcrypto_tls_creds_psk_prop_get_username, 283 qcrypto_tls_creds_psk_prop_set_username, 284 NULL); 285 } 286 287 288 static const TypeInfo qcrypto_tls_creds_psk_info = { 289 .parent = TYPE_QCRYPTO_TLS_CREDS, 290 .name = TYPE_QCRYPTO_TLS_CREDS_PSK, 291 .instance_size = sizeof(QCryptoTLSCredsPSK), 292 .instance_finalize = qcrypto_tls_creds_psk_finalize, 293 .class_size = sizeof(QCryptoTLSCredsPSKClass), 294 .class_init = qcrypto_tls_creds_psk_class_init, 295 .interfaces = (InterfaceInfo[]) { 296 { TYPE_USER_CREATABLE }, 297 { } 298 } 299 }; 300 301 302 static void 303 qcrypto_tls_creds_psk_register_types(void) 304 { 305 type_register_static(&qcrypto_tls_creds_psk_info); 306 } 307 308 309 type_init(qcrypto_tls_creds_psk_register_types); 310