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 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 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 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 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 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 static void 210 qcrypto_tls_creds_psk_finalize(Object *obj) 211 { 212 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 213 214 qcrypto_tls_creds_psk_unload(creds); 215 g_free(creds->username); 216 } 217 218 static void 219 qcrypto_tls_creds_psk_prop_set_username(Object *obj, 220 const char *value, 221 Error **errp G_GNUC_UNUSED) 222 { 223 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 224 225 creds->username = g_strdup(value); 226 } 227 228 229 static char * 230 qcrypto_tls_creds_psk_prop_get_username(Object *obj, 231 Error **errp G_GNUC_UNUSED) 232 { 233 QCryptoTLSCredsPSK *creds = QCRYPTO_TLS_CREDS_PSK(obj); 234 235 return g_strdup(creds->username); 236 } 237 238 static void 239 qcrypto_tls_creds_psk_class_init(ObjectClass *oc, void *data) 240 { 241 UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc); 242 243 ucc->complete = qcrypto_tls_creds_psk_complete; 244 245 object_class_property_add_str(oc, "username", 246 qcrypto_tls_creds_psk_prop_get_username, 247 qcrypto_tls_creds_psk_prop_set_username); 248 } 249 250 251 static const TypeInfo qcrypto_tls_creds_psk_info = { 252 .parent = TYPE_QCRYPTO_TLS_CREDS, 253 .name = TYPE_QCRYPTO_TLS_CREDS_PSK, 254 .instance_size = sizeof(QCryptoTLSCredsPSK), 255 .instance_finalize = qcrypto_tls_creds_psk_finalize, 256 .class_size = sizeof(QCryptoTLSCredsPSKClass), 257 .class_init = qcrypto_tls_creds_psk_class_init, 258 .interfaces = (InterfaceInfo[]) { 259 { TYPE_USER_CREATABLE }, 260 { } 261 } 262 }; 263 264 265 static void 266 qcrypto_tls_creds_psk_register_types(void) 267 { 268 type_register_static(&qcrypto_tls_creds_psk_info); 269 } 270 271 272 type_init(qcrypto_tls_creds_psk_register_types); 273