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