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