crypto/secret.c

   1 /*
   2  * QEMU crypto secret support
   3  *
   4  * Copyright (c) 2015 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/secret.h"
  23 #include "crypto/cipher.h"
  24 #include "qapi/error.h"
  25 #include "qom/object_interfaces.h"
  26 #include "qemu/base64.h"
  27 #include "trace.h"
  28
  29
  30 static void
  31 qcrypto_secret_load_data(QCryptoSecret *secret,
  32                          uint8_t **output,
  33                          size_t *outputlen,
  34                          Error **errp)
  35 {
  36     char *data = NULL;
  37     size_t length = 0;
  38     GError *gerr = NULL;
  39
  40     *output = NULL;
  41     *outputlen = 0;
  42
  43     if (secret->file) {
  44         if (secret->data) {
  45             error_setg(errp,
  46                        "'file' and 'data' are mutually exclusive");
  47             return;
  48         }
  49         if (!g_file_get_contents(secret->file, &data, &length, &gerr)) {
  50             error_setg(errp,
  51                        "Unable to read %s: %s",
  52                        secret->file, gerr->message);
  53             g_error_free(gerr);
  54             return;
  55         }
  56         *output = (uint8_t *)data;
  57         *outputlen = length;
  58     } else if (secret->data) {
  59         *outputlen = strlen(secret->data);
  60         *output = (uint8_t *)g_strdup(secret->data);
  61     } else {
  62         error_setg(errp, "Either 'file' or 'data' must be provided");
  63     }
  64 }
  65
  66
  67 static void qcrypto_secret_decrypt(QCryptoSecret *secret,
  68                                    const uint8_t *input,
  69                                    size_t inputlen,
  70                                    uint8_t **output,
  71                                    size_t *outputlen,
  72                                    Error **errp)
  73 {
  74     uint8_t *key = NULL, *ciphertext = NULL, *iv = NULL;
  75     size_t keylen, ciphertextlen, ivlen;
  76     QCryptoCipher *aes = NULL;
  77     uint8_t *plaintext = NULL;
  78
  79     *output = NULL;
  80     *outputlen = 0;
  81
  82     if (qcrypto_secret_lookup(secret->keyid,
  83                               &key, &keylen,
  84                               errp) < 0) {
  85         goto cleanup;
  86     }
  87
  88     if (keylen != 32) {
  89         error_setg(errp, "Key should be 32 bytes in length");
  90         goto cleanup;
  91     }
  92
  93     if (!secret->iv) {
  94         error_setg(errp, "IV is required to decrypt secret");
  95         goto cleanup;
  96     }
  97
  98     iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
  99     if (!iv) {
 100         goto cleanup;
 101     }
 102     if (ivlen != 16) {
 103         error_setg(errp, "IV should be 16 bytes in length not %zu",
 104                    ivlen);
 105         goto cleanup;
 106     }
 107
 108     aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_256,
 109                              QCRYPTO_CIPHER_MODE_CBC,
 110                              key, keylen,
 111                              errp);
 112     if (!aes) {
 113         goto cleanup;
 114     }
 115
 116     if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
 117         goto cleanup;
 118     }
 119
 120     if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
 121         ciphertext = qbase64_decode((const gchar*)input,
 122                                     inputlen,
 123                                     &ciphertextlen,
 124                                     errp);
 125         if (!ciphertext) {
 126             goto cleanup;
 127         }
 128         plaintext = g_new0(uint8_t, ciphertextlen + 1);
 129     } else {
 130         ciphertextlen = inputlen;
 131         plaintext = g_new0(uint8_t, inputlen + 1);
 132     }
 133     if (qcrypto_cipher_decrypt(aes,
 134                                ciphertext ? ciphertext : input,
 135                                plaintext,
 136                                ciphertextlen,
 137                                errp) < 0) {
 138         plaintext = NULL;
 139         goto cleanup;
 140     }
 141
 142     if (plaintext[ciphertextlen - 1] > 16 ||
 143         plaintext[ciphertextlen - 1] > ciphertextlen) {
 144         error_setg(errp, "Incorrect number of padding bytes (%d) "
 145                    "found on decrypted data",
 146                    (int)plaintext[ciphertextlen - 1]);
 147         g_free(plaintext);
 148         plaintext = NULL;
 149         goto cleanup;
 150     }
 151
 152     /* Even though plaintext may contain arbitrary NUL
 153      * ensure it is explicitly NUL terminated.
 154      */
 155     ciphertextlen -= plaintext[ciphertextlen - 1];
 156     plaintext[ciphertextlen] = '\0';
 157
 158     *output = plaintext;
 159     *outputlen = ciphertextlen;
 160
 161  cleanup:
 162     g_free(ciphertext);
 163     g_free(iv);
 164     g_free(key);
 165     qcrypto_cipher_free(aes);
 166 }
 167
 168
 169 static void qcrypto_secret_decode(const uint8_t *input,
 170                                   size_t inputlen,
 171                                   uint8_t **output,
 172                                   size_t *outputlen,
 173                                   Error **errp)
 174 {
 175     *output = qbase64_decode((const gchar*)input,
 176                              inputlen,
 177                              outputlen,
 178                              errp);
 179 }
 180
 181
 182 static void
 183 qcrypto_secret_prop_set_loaded(Object *obj,
 184                                bool value,
 185                                Error **errp)
 186 {
 187     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 188
 189     if (value) {
 190         Error *local_err = NULL;
 191         uint8_t *input = NULL;
 192         size_t inputlen = 0;
 193         uint8_t *output = NULL;
 194         size_t outputlen = 0;
 195
 196         qcrypto_secret_load_data(secret, &input, &inputlen, &local_err);
 197         if (local_err) {
 198             error_propagate(errp, local_err);
 199             return;
 200         }
 201
 202         if (secret->keyid) {
 203             qcrypto_secret_decrypt(secret, input, inputlen,
 204                                    &output, &outputlen, &local_err);
 205             g_free(input);
 206             if (local_err) {
 207                 error_propagate(errp, local_err);
 208                 return;
 209             }
 210             input = output;
 211             inputlen = outputlen;
 212         } else {
 213             if (secret->format != QCRYPTO_SECRET_FORMAT_RAW) {
 214                 qcrypto_secret_decode(input, inputlen,
 215                                       &output, &outputlen, &local_err);
 216                 g_free(input);
 217                 if (local_err) {
 218                     error_propagate(errp, local_err);
 219                     return;
 220                 }
 221                 input = output;
 222                 inputlen = outputlen;
 223             }
 224         }
 225
 226         secret->rawdata = input;
 227         secret->rawlen = inputlen;
 228     } else {
 229         g_free(secret->rawdata);
 230         secret->rawlen = 0;
 231     }
 232 }
 233
 234
 235 static bool
 236 qcrypto_secret_prop_get_loaded(Object *obj,
 237                                Error **errp G_GNUC_UNUSED)
 238 {
 239     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 240     return secret->data != NULL;
 241 }
 242
 243
 244 static void
 245 qcrypto_secret_prop_set_format(Object *obj,
 246                                int value,
 247                                Error **errp G_GNUC_UNUSED)
 248 {
 249     QCryptoSecret *creds = QCRYPTO_SECRET(obj);
 250
 251     creds->format = value;
 252 }
 253
 254
 255 static int
 256 qcrypto_secret_prop_get_format(Object *obj,
 257                                Error **errp G_GNUC_UNUSED)
 258 {
 259     QCryptoSecret *creds = QCRYPTO_SECRET(obj);
 260
 261     return creds->format;
 262 }
 263
 264
 265 static void
 266 qcrypto_secret_prop_set_data(Object *obj,
 267                              const char *value,
 268                              Error **errp)
 269 {
 270     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 271
 272     g_free(secret->data);
 273     secret->data = g_strdup(value);
 274 }
 275
 276
 277 static char *
 278 qcrypto_secret_prop_get_data(Object *obj,
 279                              Error **errp)
 280 {
 281     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 282     return g_strdup(secret->data);
 283 }
 284
 285
 286 static void
 287 qcrypto_secret_prop_set_file(Object *obj,
 288                              const char *value,
 289                              Error **errp)
 290 {
 291     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 292
 293     g_free(secret->file);
 294     secret->file = g_strdup(value);
 295 }
 296
 297
 298 static char *
 299 qcrypto_secret_prop_get_file(Object *obj,
 300                              Error **errp)
 301 {
 302     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 303     return g_strdup(secret->file);
 304 }
 305
 306
 307 static void
 308 qcrypto_secret_prop_set_iv(Object *obj,
 309                            const char *value,
 310                            Error **errp)
 311 {
 312     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 313
 314     g_free(secret->iv);
 315     secret->iv = g_strdup(value);
 316 }
 317
 318
 319 static char *
 320 qcrypto_secret_prop_get_iv(Object *obj,
 321                            Error **errp)
 322 {
 323     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 324     return g_strdup(secret->iv);
 325 }
 326
 327
 328 static void
 329 qcrypto_secret_prop_set_keyid(Object *obj,
 330                               const char *value,
 331                               Error **errp)
 332 {
 333     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 334
 335     g_free(secret->keyid);
 336     secret->keyid = g_strdup(value);
 337 }
 338
 339
 340 static char *
 341 qcrypto_secret_prop_get_keyid(Object *obj,
 342                               Error **errp)
 343 {
 344     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 345     return g_strdup(secret->keyid);
 346 }
 347
 348
 349 static void
 350 qcrypto_secret_complete(UserCreatable *uc, Error **errp)
 351 {
 352     object_property_set_bool(OBJECT(uc), true, "loaded", errp);
 353 }
 354
 355
 356 static void
 357 qcrypto_secret_finalize(Object *obj)
 358 {
 359     QCryptoSecret *secret = QCRYPTO_SECRET(obj);
 360
 361     g_free(secret->iv);
 362     g_free(secret->file);
 363     g_free(secret->keyid);
 364     g_free(secret->rawdata);
 365     g_free(secret->data);
 366 }
 367
 368 static void
 369 qcrypto_secret_class_init(ObjectClass *oc, void *data)
 370 {
 371     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 372
 373     ucc->complete = qcrypto_secret_complete;
 374
 375     object_class_property_add_bool(oc, "loaded",
 376                                    qcrypto_secret_prop_get_loaded,
 377                                    qcrypto_secret_prop_set_loaded,
 378                                    NULL);
 379     object_class_property_add_enum(oc, "format",
 380                                    "QCryptoSecretFormat",
 381                                    &QCryptoSecretFormat_lookup,
 382                                    qcrypto_secret_prop_get_format,
 383                                    qcrypto_secret_prop_set_format,
 384                                    NULL);
 385     object_class_property_add_str(oc, "data",
 386                                   qcrypto_secret_prop_get_data,
 387                                   qcrypto_secret_prop_set_data,
 388                                   NULL);
 389     object_class_property_add_str(oc, "file",
 390                                   qcrypto_secret_prop_get_file,
 391                                   qcrypto_secret_prop_set_file,
 392                                   NULL);
 393     object_class_property_add_str(oc, "keyid",
 394                                   qcrypto_secret_prop_get_keyid,
 395                                   qcrypto_secret_prop_set_keyid,
 396                                   NULL);
 397     object_class_property_add_str(oc, "iv",
 398                                   qcrypto_secret_prop_get_iv,
 399                                   qcrypto_secret_prop_set_iv,
 400                                   NULL);
 401 }
 402
 403
 404 int qcrypto_secret_lookup(const char *secretid,
 405                           uint8_t **data,
 406                           size_t *datalen,
 407                           Error **errp)
 408 {
 409     Object *obj;
 410     QCryptoSecret *secret;
 411
 412     obj = object_resolve_path_component(
 413         object_get_objects_root(), secretid);
 414     if (!obj) {
 415         error_setg(errp, "No secret with id '%s'", secretid);
 416         return -1;
 417     }
 418
 419     secret = (QCryptoSecret *)
 420         object_dynamic_cast(obj,
 421                             TYPE_QCRYPTO_SECRET);
 422     if (!secret) {
 423         error_setg(errp, "Object with id '%s' is not a secret",
 424                    secretid);
 425         return -1;
 426     }
 427
 428     if (!secret->rawdata) {
 429         error_setg(errp, "Secret with id '%s' has no data",
 430                    secretid);
 431         return -1;
 432     }
 433
 434     *data = g_new0(uint8_t, secret->rawlen + 1);
 435     memcpy(*data, secret->rawdata, secret->rawlen);
 436     (*data)[secret->rawlen] = '\0';
 437     *datalen = secret->rawlen;
 438
 439     return 0;
 440 }
 441
 442
 443 char *qcrypto_secret_lookup_as_utf8(const char *secretid,
 444                                     Error **errp)
 445 {
 446     uint8_t *data;
 447     size_t datalen;
 448
 449     if (qcrypto_secret_lookup(secretid,
 450                               &data,
 451                               &datalen,
 452                               errp) < 0) {
 453         return NULL;
 454     }
 455
 456     if (!g_utf8_validate((const gchar*)data, datalen, NULL)) {
 457         error_setg(errp,
 458                    "Data from secret %s is not valid UTF-8",
 459                    secretid);
 460         g_free(data);
 461         return NULL;
 462     }
 463
 464     return (char *)data;
 465 }
 466
 467
 468 char *qcrypto_secret_lookup_as_base64(const char *secretid,
 469                                       Error **errp)
 470 {
 471     uint8_t *data;
 472     size_t datalen;
 473     char *ret;
 474
 475     if (qcrypto_secret_lookup(secretid,
 476                               &data,
 477                               &datalen,
 478                               errp) < 0) {
 479         return NULL;
 480     }
 481
 482     ret = g_base64_encode(data, datalen);
 483     g_free(data);
 484     return ret;
 485 }
 486
 487
 488 static const TypeInfo qcrypto_secret_info = {
 489     .parent = TYPE_OBJECT,
 490     .name = TYPE_QCRYPTO_SECRET,
 491     .instance_size = sizeof(QCryptoSecret),
 492     .instance_finalize = qcrypto_secret_finalize,
 493     .class_size = sizeof(QCryptoSecretClass),
 494     .class_init = qcrypto_secret_class_init,
 495     .interfaces = (InterfaceInfo[]) {
 496         { TYPE_USER_CREATABLE },
 497         { }
 498     }
 499 };
 500
 501
 502 static void
 503 qcrypto_secret_register_types(void)
 504 {
 505     type_register_static(&qcrypto_secret_info);
 506 }
 507
 508
 509 type_init(qcrypto_secret_register_types);