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 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 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 gnutls_psk_set_server_credentials_file(creds->data.server, pskfile); 113 gnutls_psk_set_server_dh_params(creds->data.server, 114 creds->parent_obj.dh_params); 115 } else { 116 if (qcrypto_tls_creds_get_path(&creds->parent_obj, 117 QCRYPTO_TLS_CREDS_PSKFILE, 118 true, &pskfile, errp) < 0) { 119 goto cleanup; 120 } 121 122 if (creds->username) { 123 username = creds->username; 124 } else { 125 username = "qemu"; 126 } 127 if (lookup_key(pskfile, username, &key, errp) != 0) { 128 goto cleanup; 129 } 130 131 ret = gnutls_psk_allocate_client_credentials(&creds->data.client); 132 if (ret < 0) { 133 error_setg(errp, "Cannot allocate credentials: %s", 134 gnutls_strerror(ret)); 135 goto cleanup; 136 } 137 138 gnutls_psk_set_client_credentials(creds->data.client, 139 username, &key, GNUTLS_PSK_KEY_HEX); 140 } 141 142 rv = 0; 143 cleanup: 144 g_free(key.data); 145 return rv; 146 } 147 148 149 static void 150 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds) 151 { 152 if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT) { 153 if (creds->data.client) { 154 gnutls_psk_free_client_credentials(creds->data.client); 155 creds->data.client = NULL; 156 } 157 } else { 158 if (creds->data.server) { 159 gnutls_psk_free_server_credentials(creds->data.server); 160 creds->data.server = NULL; 161 } 162 } 163 if (creds->parent_obj.dh_params) { 164 gnutls_dh_params_deinit(creds->parent_obj.dh_params); 165 creds->parent_obj.dh_params = NULL; 166 } 167 } 168 169 #else /* ! CONFIG_GNUTLS */ 170 171 172 static void 173 qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED, 174 Error **errp) 175 { 176 error_setg(errp, "TLS credentials support requires GNUTLS"); 177 } 178 179 180 static void 181 qcrypto_tls_creds_psk_unload(QCryptoTLSCredsPSK *creds G_GNUC_UNUSED) 182 { 183 /* nada */ 184 } 185 186 187 #endif /* ! CONFIG_GNUTLS */ 188 189 190 static void 191 qcrypto_tls_creds_psk_prop_set_loaded(Object *obj, 192 bool value, 193 Error **errp) 194 { 195 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 196 197 qcrypto_tls_creds_psk_unload(creds); 198 if (value) { 199 qcrypto_tls_creds_psk_load(creds, errp); 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), "loaded", true, 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 object_class_property_add_str(oc, "username", 281 qcrypto_tls_creds_psk_prop_get_username, 282 qcrypto_tls_creds_psk_prop_set_username); 283 } 284 285 286 static const TypeInfo qcrypto_tls_creds_psk_info = { 287 .parent = TYPE_QCRYPTO_TLS_CREDS, 288 .name = TYPE_QCRYPTO_TLS_CREDS_PSK, 289 .instance_size = sizeof(QCryptoTLSCredsPSK), 290 .instance_finalize = qcrypto_tls_creds_psk_finalize, 291 .class_size = sizeof(QCryptoTLSCredsPSKClass), 292 .class_init = qcrypto_tls_creds_psk_class_init, 293 .interfaces = (InterfaceInfo[]) { 294 { TYPE_USER_CREATABLE }, 295 { } 296 } 297 }; 298 299 300 static void 301 qcrypto_tls_creds_psk_register_types(void) 302 { 303 type_register_static(&qcrypto_tls_creds_psk_info); 304 } 305 306 307 type_init(qcrypto_tls_creds_psk_register_types); 308