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 2.1 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
  32static int
  33lookup_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
  68static int
  69qcrypto_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
 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