qemu/crypto/tlscredspsk.c
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   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 "qom/object_interfaces.h"
  26#include "trace.h"
  27
  28
  29#ifdef CONFIG_GNUTLS
  30
  31static int
  32lookup_key(const char *pskfile, const char *username, gnutls_datum_t *key,
  33           Error **errp)
  34{
  35    const size_t ulen = strlen(username);
  36    GError *gerr = NULL;
  37    char *content = NULL;
  38    char **lines = NULL;
  39    size_t clen = 0, i;
  40    int ret = -1;
  41
  42    if (!g_file_get_contents(pskfile, &content, &clen, &gerr)) {
  43        error_setg(errp, "Cannot read PSK file %s: %s",
  44                   pskfile, gerr->message);
  45        g_error_free(gerr);
  46        return -1;
  47    }
  48
  49    lines = g_strsplit(content, "\n", -1);
  50    for (i = 0; lines[i] != NULL; ++i) {
  51        if (strncmp(lines[i], username, ulen) == 0 && lines[i][ulen] == ':') {
  52            key->data = (unsigned char *) g_strdup(&lines[i][ulen + 1]);
  53            key->size = strlen(lines[i]) - ulen - 1;
  54            ret = 0;
  55            goto out;
  56        }
  57    }
  58    error_setg(errp, "Username %s not found in PSK file %s",
  59               username, pskfile);
  60
  61 out:
  62    free(content);
  63    g_strfreev(lines);
  64    return ret;
  65}
  66
  67static int
  68qcrypto_tls_creds_psk_load(QCryptoTLSCredsPSK *creds,
  69                           Error **errp)
  70{
  71    char *pskfile = NULL, *dhparams = NULL;
  72    const char *username;
  73    int ret;
  74    int rv = -1;
  75    gnutls_datum_t key = { .data = NULL };
  76
  77    trace_qcrypto_tls_creds_psk_load(creds,
  78            creds->parent_obj.dir ? creds->parent_obj.dir : "<nodir>");
  79
  80    if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
  81        if (creds->username) {
  82            error_setg(errp, "username should not be set when endpoint=server");
  83            goto cleanup;
  84        }
  85
  86        if (qcrypto_tls_creds_get_path(&creds->parent_obj,
  87                                       QCRYPTO_TLS_CREDS_DH_PARAMS,
  88                                       false, &dhparams, errp) < 0 ||
  89            qcrypto_tls_creds_get_path(&creds->parent_obj,
  90                                       QCRYPTO_TLS_CREDS_PSKFILE,
  91                                       true, &pskfile, errp) < 0) {
  92            goto cleanup;
  93        }
  94
  95        ret = gnutls_psk_allocate_server_credentials(&creds->data.server);
  96        if (ret < 0) {
  97            error_setg(errp, "Cannot allocate credentials: %s",
  98                       gnutls_strerror(ret));
  99            goto cleanup;
 100        }
 101
 102        if (qcrypto_tls_creds_get_dh_params_file(&creds->parent_obj, dhparams,
 103                                                 &creds->parent_obj.dh_params,
 104                                                 errp) < 0) {
 105            goto cleanup;
 106        }
 107
 108        gnutls_psk_set_server_credentials_file(creds->data.server, pskfile);
 109        gnutls_psk_set_server_dh_params(creds->data.server,
 110                                        creds->parent_obj.dh_params);
 111    } else {
 112        if (qcrypto_tls_creds_get_path(&creds->parent_obj,
 113                                       QCRYPTO_TLS_CREDS_PSKFILE,
 114                                       true, &pskfile, errp) < 0) {
 115            goto cleanup;
 116        }
 117
 118        if (creds->username) {
 119            username = creds->username;
 120        } else {
 121            username = "qemu";
 122        }
 123        if (lookup_key(pskfile, username, &key, errp) != 0) {
 124            goto cleanup;
 125        }
 126
 127        ret = gnutls_psk_allocate_client_credentials(&creds->data.client);
 128        if (ret < 0) {
 129            error_setg(errp, "Cannot allocate credentials: %s",
 130                       gnutls_strerror(ret));
 131            goto cleanup;
 132        }
 133
 134        gnutls_psk_set_client_credentials(creds->data.client,
 135                                          username, &key, GNUTLS_PSK_KEY_HEX);
 136    }
 137
 138    rv = 0;
 139 cleanup:
 140    g_free(key.data);
 141    g_free(pskfile);
 142    g_free(dhparams);
 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