securityd/securityd_service/securityd_service/main.c

   1 /* Copyright (c) 2012-2014 Apple Inc. All Rights Reserved. */
   2
   3 #include "securityd_service.h"
   4 #include "securityd_service_client.h"
   5 #include <libaks.h>
   6
   7 #include <sandbox.h>
   8 #include <vproc.h>
   9 #include <xpc/xpc.h>
  10 #include <xpc/private.h>
  11 #include <dispatch/dispatch.h>
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <sys/codesign.h>
  15 #include <stdio.h>
  16 #include <errno.h>
  17 #include <assert.h>
  18 #include <syslog.h>
  19 #include <unistd.h>
  20 #include <pwd.h>
  21 #include <uuid/uuid.h>
  22 #include <bsm/libbsm.h>
  23 #include <copyfile.h>
  24 #include <AssertMacros.h>
  25 #include <Security/Security.h>
  26 #include <Security/SecTask.h>
  27 #include <Security/SecTaskPriv.h>
  28 #include <Security/SecKeychainPriv.h>
  29
  30 #include <IOKit/IOKitLib.h>
  31 #include <Kernel/IOKit/crypto/AppleFDEKeyStoreDefs.h>
  32
  33 #if DEBUG
  34 #define LOG(...)    syslog(LOG_ERR, ##__VA_ARGS__);
  35 #else
  36 #define LOG(...)
  37 #endif
  38
  39 static bool check_signature(xpc_connection_t connection);
  40
  41 static pid_t get_caller_pid(audit_token_t * token)
  42 {
  43     pid_t pid = 0;
  44     if (token) {
  45         audit_token_to_au32(*token, NULL, NULL, NULL, NULL, NULL, &pid, NULL, NULL);
  46     }
  47     return pid;
  48 }
  49
  50 // exported from libaks.a
  51 kern_return_t aks_register_for_notifications(mach_port_t server_port, uintptr_t message_id);
  52 kern_return_t aks_stash_escrow(keybag_handle_t handle, bool create, const void * secret, int secret_len, const void * in_data, int in_data_len, void ** out_data, int * out_data_len);
  53
  54 const char * kb_home_path = "Library/Keychains";
  55 const char * kb_user_bag = "user.kb";
  56 const char * kb_stash_bag = "stash.kb";
  57
  58 #define HEXBUF_LEN 2048
  59
  60 typedef struct {
  61     uid_t uid;
  62     gid_t gid;
  63     char * name;
  64     char * home;
  65 } service_user_record_t;
  66
  67 typedef enum {
  68     kb_bag_type_user,
  69     kb_bag_type_stash
  70 } kb_bag_type_t;
  71
  72 static io_connect_t
  73 openiodev(void)
  74 {
  75     io_registry_entry_t service;
  76     io_connect_t conn;
  77     kern_return_t kr;
  78
  79     service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching(kAppleFDEKeyStoreServiceName));
  80     if (service == IO_OBJECT_NULL)
  81         return IO_OBJECT_NULL;
  82
  83     kr = IOServiceOpen(service, mach_task_self(), 0, &conn);
  84     if (kr != KERN_SUCCESS)
  85         return IO_OBJECT_NULL;
  86
  87     kr = IOConnectCallMethod(conn, kAppleFDEKeyStoreUserClientOpen, NULL, 0, NULL, 0, NULL, NULL, NULL, NULL);
  88     if (kr != KERN_SUCCESS) {
  89         IOServiceClose(conn);
  90         return IO_OBJECT_NULL;
  91     }
  92
  93     return conn;
  94 }
  95
  96 static void
  97 closeiodev(io_connect_t conn)
  98 {
  99     kern_return_t kr;
 100     kr = IOConnectCallMethod(conn, kAppleFDEKeyStoreUserClientClose, NULL, 0, NULL, 0, NULL, NULL, NULL, NULL);
 101     if (kr != KERN_SUCCESS)
 102         return;
 103     IOServiceClose(conn);
 104 }
 105
 106 static dispatch_queue_t
 107 _kb_service_get_dispatch_queue()
 108 {
 109     static dispatch_once_t onceToken = 0;
 110     static dispatch_queue_t connection_queue = NULL;
 111
 112     dispatch_once(&onceToken, ^{
 113         connection_queue = dispatch_queue_create("kb-service-queue", DISPATCH_QUEUE_SERIAL);
 114     });
 115
 116     return connection_queue;
 117 }
 118
 119 static service_user_record_t * get_user_record(uid_t uid)
 120 {
 121     service_user_record_t * ur = NULL;
 122     long bufsize = 0;
 123     if ((bufsize = sysconf(_SC_GETPW_R_SIZE_MAX)) == -1) {
 124         bufsize = 4096;
 125     }
 126     char buf[bufsize];
 127     struct passwd pwbuf, *pw = NULL;
 128     if ((getpwuid_r(uid, &pwbuf, buf, bufsize, &pw) == 0) && pw != NULL) {
 129         ur = calloc(1u, sizeof(service_user_record_t));
 130         require(ur, done);
 131         ur->uid = pw->pw_uid;
 132         ur->gid = pw->pw_gid;
 133         ur->home = strdup(pw->pw_dir);
 134         ur->name = strdup(pw->pw_name);
 135     } else {
 136         syslog(LOG_ERR, "failed to lookup user record for uid: %d", uid);
 137     }
 138
 139 done:
 140     return ur;
 141 }
 142
 143 static void free_user_record(service_user_record_t * ur)
 144 {
 145     if (ur != NULL) {
 146         if (ur->home) {
 147             free(ur->home);
 148         }
 149         if (ur->name) {
 150             free(ur->name);
 151         }
 152         free(ur);
 153     }
 154 }
 155
 156 static const char * get_host_uuid()
 157 {
 158     static uuid_string_t hostuuid = {};
 159     static dispatch_once_t onceToken;
 160     dispatch_once(&onceToken, ^{
 161         struct timespec timeout = {30, 0};
 162         uuid_t uuid = {};
 163         if (gethostuuid(uuid, &timeout) == 0) {
 164             uuid_unparse(uuid, hostuuid);
 165         } else {
 166             syslog(LOG_ERR, "failed to get host uuid");
 167         }
 168     });
 169
 170     return hostuuid;
 171 }
 172
 173 static char *
 174 _kb_copy_bag_filename(service_user_record_t * ur, kb_bag_type_t type)
 175 {
 176     char * bag_file = NULL;
 177     const char * name = NULL;
 178
 179     require(ur, done);
 180     switch(type) {
 181         case kb_bag_type_user:
 182             name = kb_user_bag;
 183             break;
 184         case kb_bag_type_stash:
 185             name = kb_stash_bag;
 186             break;
 187         default:
 188             goto done;
 189     }
 190
 191     bag_file = calloc(1u, PATH_MAX);
 192     require(bag_file, done);
 193
 194     snprintf(bag_file, PATH_MAX, "%s/%s/%s/%s", ur->home, kb_home_path, get_host_uuid(), name);
 195
 196 done:
 197     return bag_file;
 198 }
 199
 200 static bool
 201 _kb_verify_create_path(service_user_record_t * ur)
 202 {
 203     bool created = false;
 204     struct stat st_info = {};
 205     char new_path[PATH_MAX] = {};
 206     char kb_path[PATH_MAX] = {};
 207     snprintf(kb_path, sizeof(kb_path), "%s/%s/%s", ur->home, kb_home_path, get_host_uuid());
 208     if (lstat(kb_path, &st_info) == 0) {
 209         if (S_ISDIR(st_info.st_mode)) {
 210             created = true;
 211         } else {
 212             syslog(LOG_ERR, "invalid directory at '%s' moving aside", kb_path);
 213             snprintf(new_path, sizeof(new_path), "%s-invalid", kb_path);
 214             unlink(new_path);
 215             if (rename(kb_path, new_path) != 0) {
 216                 syslog(LOG_ERR, "failed to rename file: %s (%s)", kb_path, strerror(errno));
 217                 goto done;
 218             }
 219         }
 220     }
 221     if (!created) {
 222         require_action(mkpath_np(kb_path, 0700) == 0, done, syslog(LOG_ERR, "could not create path: %s (%s)", kb_path, strerror(errno)));
 223         created = true;
 224     }
 225
 226 done:
 227     return created;
 228 }
 229
 230 static void
 231 _set_thread_credentials(service_user_record_t * ur)
 232 {
 233     int rc = pthread_setugid_np(ur->uid, ur->gid);
 234     if (rc) { syslog(LOG_ERR, "failed to set thread credential: %i (%s)", errno, strerror(errno)); }
 235
 236     rc = initgroups(ur->name, ur->gid);
 237     if (rc) { syslog(LOG_ERR, "failed to initgroups: %i", rc); }
 238 }
 239
 240 static void
 241 _clear_thread_credentials()
 242 {
 243     int rc = pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE);
 244     if (rc) { syslog(LOG_ERR, "failed to reset thread credential: %i (%s)", errno, strerror(errno)); }
 245 }
 246
 247 static bool
 248 _kb_bag_exists(service_user_record_t * ur, const char * bag_file)
 249 {
 250     bool exists = false;
 251     struct stat st_info = {};
 252     char new_file[PATH_MAX] = {};
 253
 254     require(ur, done);
 255
 256     _set_thread_credentials(ur);
 257     if (lstat(bag_file, &st_info) == 0) {
 258         if (S_ISREG(st_info.st_mode)) {
 259             exists = true;
 260         } else {
 261             syslog(LOG_ERR, "invalid file at '%s' moving aside", bag_file);
 262             snprintf(new_file, sizeof(new_file), "%s-invalid", bag_file);
 263             unlink(new_file);
 264             if (rename(bag_file, new_file) != 0) {
 265                 syslog(LOG_ERR, "failed to rename file: %s (%s)", bag_file, strerror(errno));
 266             }
 267         }
 268     }
 269
 270 done:
 271     _clear_thread_credentials();
 272     return exists;
 273 }
 274
 275 static bool
 276 _kb_save_bag_to_disk(service_user_record_t * ur, const char * bag_file, void * data, size_t length)
 277 {
 278     bool result = false;
 279     int fd = -1;
 280
 281     require(bag_file, done);
 282
 283     _set_thread_credentials(ur);
 284     require(_kb_verify_create_path(ur), done);
 285
 286     fd = open(bag_file, O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW, 0600);
 287     require_action(fd != -1, done, syslog(LOG_ERR, "could not create file: %s (%s)", bag_file, strerror(errno)));
 288     require_action(write(fd, data, length) != -1, done, syslog(LOG_ERR, "failed to write keybag to disk %s", strerror(errno)));
 289
 290     result = true;
 291
 292 done:
 293     if (fd != -1) { close(fd); }
 294     _clear_thread_credentials();
 295     return result;
 296 }
 297
 298 static bool
 299 _kb_load_bag_from_disk(service_user_record_t * ur, const char * bag_file, uint8_t ** data, size_t * length)
 300 {
 301     bool result = false;
 302     int fd = -1;
 303     uint8_t * buf = NULL;
 304     size_t buf_size = 0;
 305     struct stat st_info = {};
 306
 307     require(bag_file, done);
 308
 309     _set_thread_credentials(ur);
 310     require(_kb_verify_create_path(ur), done);
 311     require_quiet(lstat(bag_file, &st_info) == 0, done);
 312     require_action(S_ISREG(st_info.st_mode), done, syslog(LOG_ERR, "failed to load, not a file: %s", bag_file));
 313     buf_size = (size_t)st_info.st_size;
 314
 315     fd = open(bag_file, O_RDONLY | O_NOFOLLOW);
 316     require_action(fd != -1, done, syslog(LOG_ERR, "could not open file: %s (%s)", bag_file, strerror(errno)));
 317
 318     buf = (uint8_t *)calloc(1u, buf_size);
 319     require(buf != NULL, done);
 320     require(read(fd, buf, buf_size) == buf_size, done);
 321
 322     *data = buf;
 323     *length = buf_size;
 324     buf = NULL;
 325     result = true;
 326
 327 done:
 328     if (fd != -1) { close(fd); }
 329     if (buf) { free(buf); }
 330     _clear_thread_credentials();
 331     return result;
 332 }
 333
 334 static void
 335 _kb_rename_bag_on_disk(service_user_record_t * ur, const char * bag_file)
 336 {
 337     char new_file[PATH_MAX] = {};
 338     if (bag_file) {
 339         _set_thread_credentials(ur);
 340         snprintf(new_file, sizeof(new_file), "%s-invalid", bag_file);
 341         unlink(new_file);
 342         rename(bag_file, new_file);
 343         _clear_thread_credentials();
 344     }
 345 }
 346
 347 static void
 348 _kb_delete_bag_on_disk(service_user_record_t * ur, const char * bag_file)
 349 {
 350     if (bag_file) {
 351         _set_thread_credentials(ur);
 352         unlink(bag_file);
 353         _clear_thread_credentials();
 354     }
 355 }
 356
 357 static int
 358 _kb_get_session_handle(service_context_t * context, keybag_handle_t * handle_out)
 359 {
 360     int rc = KB_BagNotLoaded;
 361     keybag_handle_t session_handle = bad_keybag_handle;
 362     require_noerr_quiet(aks_get_system(context->s_uid, &session_handle), done);
 363
 364     *handle_out = session_handle;
 365     rc = KB_Success;
 366
 367 done:
 368     return rc;
 369 }
 370
 371 static void update_keybag_handle(keybag_handle_t handle)
 372 {
 373     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 374         uid_t uid = abs(handle);
 375         uint8_t * buf = NULL;
 376         size_t buf_size = 0;
 377         service_user_record_t * ur = NULL;
 378         char * bag_file = NULL;
 379
 380         require_noerr(aks_save_bag(handle, (void**)&buf, (int*)&buf_size), done);
 381         require(ur = get_user_record(uid), done);
 382         require(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user), done);
 383         require(_kb_save_bag_to_disk(ur, bag_file, buf, buf_size), done);
 384
 385         syslog(LOG_NOTICE, "successfully updated handle %d", handle);
 386
 387     done:
 388         if (buf) free(buf);
 389         if (ur) free_user_record(ur);
 390         if (bag_file) free(bag_file);
 391     });
 392 }
 393
 394 static int
 395 service_kb_create(service_context_t * context, const void * secret, int secret_len)
 396 {
 397     __block int rc = KB_GeneralError;
 398
 399     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 400         uint8_t * buf = NULL;
 401         size_t buf_size = 0;
 402         keybag_handle_t session_handle = bad_keybag_handle;
 403         service_user_record_t * ur = get_user_record(context->s_uid);
 404         char * bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user);
 405
 406         require(bag_file, done);
 407
 408         // check for the existance of the bagfile
 409         require_action(!_kb_bag_exists(ur, bag_file), done, rc = KB_BagExists);
 410
 411         require_noerr(rc = aks_create_bag(secret, secret_len, kAppleKeyStoreDeviceBag, &session_handle), done);
 412         require_noerr(rc = aks_save_bag(session_handle, (void**)&buf, (int*)&buf_size), done);
 413         require_action(_kb_save_bag_to_disk(ur, bag_file, buf, buf_size), done, rc = KB_BagError);
 414         require_noerr(rc = aks_set_system(session_handle, context->s_uid), done);
 415         aks_unload_bag(session_handle);
 416         require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 417
 418         if (secret && rc == KB_Success) {
 419             aks_unlock_bag(session_handle, secret, secret_len);
 420         }
 421
 422     done:
 423         if (buf) free(buf);
 424         if (bag_file) { free(bag_file); }
 425         if (ur) free_user_record(ur);
 426     });
 427
 428     return rc;
 429 }
 430
 431 static int
 432 service_kb_load(service_context_t * context)
 433 {
 434     __block int rc = KB_GeneralError;
 435
 436     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 437         uint8_t * buf = NULL;
 438         size_t buf_size = 0;
 439         keybag_handle_t session_handle = bad_keybag_handle;
 440         service_user_record_t * ur = NULL;
 441         char * bag_file = NULL;
 442
 443         rc = aks_get_system(context->s_uid, &session_handle);
 444         if (rc == kIOReturnNotFound) {
 445             require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 446             require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user), done, rc = KB_GeneralError);
 447             require_action_quiet(_kb_load_bag_from_disk(ur, bag_file, &buf, &buf_size), done, rc = KB_BagNotFound);
 448             rc = aks_load_bag(buf, (int)buf_size, &session_handle);
 449             if (rc == kIOReturnNotPermitted) {
 450                 syslog(LOG_ERR, "error loading keybag for uid (%i) in session (%i)", context->s_uid, context->s_id);
 451                 _kb_rename_bag_on_disk(ur, bag_file);
 452                 rc = KB_BagNotFound;
 453             }
 454             require_noerr(rc, done);
 455             require_noerr(rc = aks_set_system(session_handle, context->s_uid), done);
 456             aks_unload_bag(session_handle);
 457         }
 458         require(rc == KB_Success, done);
 459
 460     done:
 461         if (buf) free(buf);
 462         if (ur) free_user_record(ur);
 463         if (bag_file) free(bag_file);
 464     });
 465
 466     return rc;
 467 }
 468
 469 static int
 470 service_kb_unload(service_context_t *context)
 471 {
 472     __block int rc = KB_GeneralError;
 473
 474     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 475         keybag_handle_t session_handle = bad_keybag_handle;
 476
 477         rc = aks_get_system(context->s_uid, &session_handle);
 478         if (rc == kIOReturnNotFound) {
 479             // No session bag, nothing to do
 480             rc = KB_Success;
 481             return;
 482         } else if (rc != kIOReturnSuccess) {
 483             syslog(LOG_ERR, "error locating session keybag for uid (%i) in session (%i)", context->s_uid, context->s_id);
 484             rc = KB_BagError;
 485             return;
 486         }
 487
 488         rc = aks_unload_bag(session_handle);
 489         if (rc != kAKSReturnSuccess) {
 490             syslog(LOG_ERR, "error unloading keybag for uid (%i) in session (%i)", context->s_uid, context->s_id);
 491             rc = KB_BagError;
 492         } else {
 493             syslog(LOG_ERR, "successfully unloaded keybag (%ld) for uid (%i) in session (%i)", (long)session_handle, context->s_uid, context->s_id);
 494         }
 495     });
 496
 497     return rc;
 498 }
 499
 500 static int
 501 service_kb_save(service_context_t * context)
 502 {
 503     __block int rc = KB_GeneralError;
 504     keybag_handle_t session_handle;
 505     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 506
 507     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 508         uint8_t * buf = NULL;
 509         size_t buf_size = 0;
 510         service_user_record_t * ur = NULL;
 511         char * bag_file = NULL;
 512
 513         require_noerr(rc = aks_save_bag(session_handle, (void**)&buf, (int*)&buf_size), done);
 514         require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 515         require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user), done, rc = KB_GeneralError);
 516         require_action(_kb_save_bag_to_disk(ur, bag_file, buf, buf_size), done, rc = KB_BagError);
 517
 518         rc = KB_Success;
 519
 520     done:
 521         if (buf) free(buf);
 522         if (ur) free_user_record(ur);
 523         if (bag_file) free(bag_file);
 524         return;
 525     });
 526
 527 done:
 528     return rc;
 529 }
 530
 531 static int
 532 service_kb_unlock(service_context_t * context, const void * secret, int secret_len)
 533 {
 534     int rc = KB_GeneralError;
 535     keybag_handle_t session_handle;
 536     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 537
 538     rc = aks_unlock_bag(session_handle, secret, secret_len);
 539
 540 done:
 541     return rc;
 542 }
 543
 544 static int
 545 service_kb_lock(service_context_t * context)
 546 {
 547     // this call has been disabled
 548     return -1;
 549 }
 550
 551 static int
 552 service_kb_change_secret(service_context_t * context, const void * secret, int secret_len, const void * new_secret, int new_secret_len)
 553 {
 554     __block int rc = KB_GeneralError;
 555     keybag_handle_t session_handle;
 556     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 557
 558     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 559         uint8_t * buf = NULL;
 560         size_t buf_size = 0;
 561         service_user_record_t * ur = NULL;
 562         char * bag_file = NULL;
 563
 564         require_noerr(rc = aks_change_secret(session_handle, secret, secret_len, new_secret, new_secret_len, NULL, NULL), done);
 565         require_noerr(rc = aks_save_bag(session_handle, (void**)&buf, (int*)&buf_size), done);
 566         require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 567         require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user), done, rc = KB_GeneralError);
 568         require_action(_kb_save_bag_to_disk(ur, bag_file, buf, buf_size), done, rc = KB_BagError);
 569
 570         rc = KB_Success;
 571
 572     done:
 573         if (buf) free(buf);
 574         if (ur) free_user_record(ur);
 575         if (bag_file) free(bag_file);
 576         return;
 577     });
 578
 579 done:
 580     return rc;
 581 }
 582
 583 static int
 584 service_kb_reset(service_context_t * context, const void * secret, int secret_len)
 585 {
 586     __block int rc = KB_GeneralError;
 587     service_user_record_t * ur = NULL;
 588     char * bag_file = NULL;
 589
 590     require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 591     require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_user), done, rc = KB_GeneralError);
 592
 593     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 594         uint8_t * buf = NULL;
 595         size_t buf_size = 0;
 596         keybag_handle_t session_handle = bad_keybag_handle;
 597
 598         syslog(LOG_ERR, "resetting keybag for uid (%i) in session (%i)", context->s_uid, context->s_id);
 599         _kb_rename_bag_on_disk(ur, bag_file);
 600
 601         require_noerr(rc = aks_create_bag(secret, secret_len, kAppleKeyStoreDeviceBag, &session_handle), done);
 602         require_noerr(rc = aks_save_bag(session_handle, (void**)&buf, (int*)&buf_size), done);
 603         require_action(_kb_save_bag_to_disk(ur, bag_file, buf, buf_size), done, rc = KB_BagError);
 604         require_noerr(rc = aks_set_system(session_handle, context->s_uid), done);
 605         aks_unload_bag(session_handle);
 606         require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 607
 608         if (secret && rc == KB_Success) {
 609             aks_unlock_bag(session_handle, secret, secret_len);
 610         }
 611
 612     done:
 613         if (buf) free(buf);
 614         return;
 615     });
 616
 617 done:
 618     if (ur) free_user_record(ur);
 619     if (bag_file) free(bag_file);
 620     return rc;
 621 }
 622
 623 static int
 624 service_kb_is_locked(service_context_t * context, xpc_object_t reply)
 625 {
 626     int rc = KB_GeneralError;
 627     keybag_state_t state;
 628     keybag_handle_t session_handle;
 629     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 630
 631     require_noerr(rc = aks_get_lock_state(session_handle, &state), done);
 632
 633     xpc_dictionary_set_bool(reply, SERVICE_XPC_LOCKED, state & keybag_state_locked);
 634     xpc_dictionary_set_bool(reply, SERVICE_XPC_NO_PIN, state & keybag_state_no_pin);
 635
 636 done:
 637     return rc;
 638 }
 639
 640 static int
 641 service_kb_stash_create(service_context_t * context, const void * key, unsigned key_size)
 642 {
 643     int rc = KB_GeneralError;
 644     char * bag_file = NULL;
 645     keybag_handle_t session_handle;
 646     service_user_record_t * ur = NULL;
 647     void * stashbag = NULL;
 648     int stashbag_size = 0;
 649     __block bool saved = false;
 650
 651     require(key, done);
 652     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 653     require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 654     require_noerr(rc = aks_stash_escrow(session_handle, true, key, key_size, NULL, 0, (void**)&stashbag, &stashbag_size), done);
 655     require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_stash), done, rc = KB_GeneralError);
 656
 657     // sync writing the bag to disk
 658     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 659         saved = _kb_save_bag_to_disk(ur, bag_file, stashbag, stashbag_size);
 660     });
 661     require_action(saved, done, rc = KB_BagError);
 662     rc = KB_Success;
 663
 664 done:
 665     if (stashbag) { free(stashbag); }
 666     if (bag_file) { free(bag_file); }
 667     if (ur) free_user_record(ur);
 668     return rc;
 669 }
 670
 671 static int
 672 service_kb_stash_load(service_context_t * context, const void * key, unsigned key_size, bool nondestructive)
 673 {
 674     __block int rc = KB_GeneralError;
 675     char * bag_file = NULL;
 676     keybag_handle_t session_handle;
 677     service_user_record_t * ur = NULL;
 678     __block uint8_t * stashbag = NULL;
 679     __block size_t stashbag_size = 0;
 680
 681     require(key, done);
 682     require_noerr(rc = _kb_get_session_handle(context, &session_handle), done);
 683     require_action(ur = get_user_record(context->s_uid), done, rc = KB_GeneralError);
 684     require_action(bag_file = _kb_copy_bag_filename(ur, kb_bag_type_stash), done, rc = KB_GeneralError);
 685
 686     // sync loading the bag from disk
 687     dispatch_sync(_kb_service_get_dispatch_queue(), ^{
 688         if (!_kb_load_bag_from_disk(ur, bag_file, &stashbag, &stashbag_size)) {
 689             rc = KB_BagError;
 690         }
 691     });
 692     require_noerr(rc, done);
 693
 694     require_noerr(rc = aks_stash_escrow(session_handle, false, key, key_size, stashbag, (int)stashbag_size, NULL, NULL), done);
 695     rc = KB_Success;
 696
 697 done:
 698     if (stashbag) { free(stashbag); }
 699     if ((bag_file) && (!nondestructive)) {
 700         _kb_delete_bag_on_disk(ur, bag_file);
 701         free(bag_file);
 702     }
 703     if (ur) free_user_record(ur);
 704     return rc;
 705 }
 706
 707 //
 708 // Get the keychain master key from the AppleFDEKeyStore.
 709 // Note that this is a one-time call - the master key is
 710 // removed from the keystore after it is returned.
 711 // Requires the entitlement: com.apple.private.securityd.keychain
 712 //
 713 OSStatus service_stash_get_key(service_context_t * context, xpc_object_t event, xpc_object_t reply)
 714 {
 715     getStashKey_InStruct_t inStruct;
 716     getStashKey_OutStruct_t outStruct;
 717     size_t outSize = sizeof(outStruct);
 718     kern_return_t kr = KERN_INVALID_ARGUMENT;
 719
 720     io_connect_t conn = openiodev();
 721     require(conn, done);
 722     inStruct.type = kAppleFDEKeyStoreStash_master;
 723
 724     kr = IOConnectCallMethod(conn, kAppleFDEKeyStore_getStashKey,
 725                              NULL, 0,
 726                              &inStruct, sizeof(inStruct),
 727                              NULL, NULL,
 728                              &outStruct, &outSize);
 729
 730     if (kr == KERN_SUCCESS) {
 731         xpc_dictionary_set_data(reply, SERVICE_XPC_KEY, outStruct.outBuf.key.key, outStruct.outBuf.key.keysize);
 732         service_kb_stash_load(context, outStruct.outBuf.key.key, outStruct.outBuf.key.keysize, false);
 733     }
 734
 735 done:
 736     if (conn)
 737         closeiodev(conn);
 738
 739     return kr;
 740 }
 741
 742 //
 743 // Stash the keychain master key in the AppleFDEKeyStore and
 744 // flag it as the keychain master key to be added to the
 745 // reboot NVRAM blob.
 746 // This requires two calls to the AKS: the first to store the
 747 // key and get its uuid.  The second uses the uuid to flag the
 748 // key for blob inclusion.
 749 //
 750 OSStatus service_stash_set_key(service_context_t * context, xpc_object_t event, xpc_object_t reply)
 751 {
 752     kern_return_t kr = KERN_INVALID_ARGUMENT;
 753     io_connect_t conn = IO_OBJECT_NULL;
 754     size_t keydata_len = 0;
 755     size_t len;
 756
 757     keybag_state_t state;
 758     keybag_handle_t session_handle;
 759     require_noerr(_kb_get_session_handle(context, &session_handle), done);
 760     require_noerr(aks_get_lock_state(session_handle, &state), done);
 761     require_action(!(state & keybag_lock_locked), done, kr = CSSMERR_CSP_OS_ACCESS_DENIED; LOG("stash failed keybag locked"));
 762
 763     conn = openiodev();
 764     require(conn, done);
 765
 766     // Store the key in the keystore and get its uuid
 767     setKeyGetUUID_InStruct_t inStruct1;
 768     uuid_OutStruct_t outStruct1;
 769
 770
 771     const uint8_t *keydata = xpc_dictionary_get_data(event, SERVICE_XPC_KEY, &keydata_len);
 772     require(keydata, done);
 773
 774     memcpy(&inStruct1.inKey.key.key, keydata, keydata_len);
 775     inStruct1.inKey.key.keysize = (cryptosize_t) keydata_len;
 776     len = sizeof(outStruct1);
 777     kr = IOConnectCallMethod(conn, kAppleFDEKeyStore_setKeyGetUUID,
 778                              NULL, 0,
 779                              &inStruct1, sizeof(inStruct1),
 780                              NULL, NULL,
 781                              &outStruct1, &len);
 782     require(kr == KERN_SUCCESS, done);
 783
 784     // Now using the uuid stash it as the master key
 785     setStashKey_InStruct_t inStruct2;
 786     memcpy(&inStruct2.uuid, &outStruct1.uuid, sizeof(outStruct1.uuid));
 787     inStruct2.type  = kAppleFDEKeyStoreStash_master;
 788
 789     kr = IOConnectCallMethod(conn, kAppleFDEKeyStore_setStashKey,
 790                              NULL, 0,
 791                              &inStruct2, sizeof(inStruct2),
 792                              NULL, NULL,
 793                              NULL, NULL);
 794
 795     if  (kr == KERN_SUCCESS) {
 796         service_kb_stash_create(context, keydata, (unsigned)keydata_len);
 797     }
 798 done:
 799     if (conn)
 800         closeiodev(conn);
 801
 802     return kr;
 803 }
 804
 805 //
 806 // Load the master stash key
 807 //
 808 OSStatus service_stash_load_key(service_context_t * context, xpc_object_t event, xpc_object_t reply)
 809 {
 810     kern_return_t kr = KERN_SUCCESS;
 811     size_t keydata_len = 0;
 812
 813     const uint8_t *keydata = xpc_dictionary_get_data(event, SERVICE_XPC_KEY, &keydata_len);
 814     require(keydata, done);
 815
 816     kr = service_kb_stash_load(context, keydata, (cryptosize_t) keydata_len, true);
 817 done:
 818
 819     return kr;
 820 }
 821
 822 //
 823 // Signal the AppleFDEKeyStore to take the tagged FDE key
 824 // and keychain master key, stash them in an encrypted
 825 // blob structure and write the blob to NVRAM.  The random
 826 // encryption key is written to the SMC.
 827 //
 828 #if DEBUG
 829 OSStatus service_stash_blob(xpc_object_t event, xpc_object_t reply)
 830 {
 831     kern_return_t kr = KERN_INVALID_ARGUMENT;
 832
 833     io_connect_t conn = openiodev();
 834     require(conn, done);
 835
 836     kr = IOConnectCallMethod(conn, kAppleFDEKeyStore_commitStash,
 837                              NULL, 0,
 838                              NULL, 0,
 839                              NULL, NULL,
 840                              NULL, NULL);
 841 done:
 842     if (conn)
 843         closeiodev(conn);
 844
 845     return kr;
 846 }
 847 #endif
 848
 849 bool peer_has_entitlement(xpc_connection_t peer, const char * entitlement)
 850 {
 851     bool entitled = false;
 852
 853     xpc_object_t value = xpc_connection_copy_entitlement_value(peer, entitlement);
 854     if (value && (xpc_get_type(value) == XPC_TYPE_BOOL)) {
 855         entitled = xpc_bool_get_value(value);
 856     }
 857
 858     if (value) xpc_release(value);
 859     return entitled;
 860 }
 861
 862 static char * sel_to_char(uint64_t sel)
 863 {
 864     switch (sel) {
 865         case SERVICE_STASH_SET_KEY:
 866             return "set_key";
 867         case SERVICE_STASH_GET_KEY:
 868             return "get_key";
 869         case SERVICE_STASH_BLOB:
 870             return "stash_blob";
 871         case SERVICE_KB_LOAD:
 872             return "kb_load";
 873         case SERVICE_KB_SAVE:
 874             return "kb_save";
 875         case SERVICE_KB_UNLOCK:
 876             return "kb_unlock";
 877         case SERVICE_KB_LOCK:
 878             return "kb_lock";
 879         case SERVICE_KB_CHANGE_SECRET:
 880             return "kb_change_secret";
 881         case SERVICE_KB_CREATE:
 882             return "kb_create";
 883         case SERVICE_KB_IS_LOCKED:
 884             return "kb_is_locked";
 885         case SERVICE_KB_RESET:
 886             return "kb_reset";
 887         case SERVICE_KB_UNLOAD:
 888             return "kb_unload";
 889         default:
 890             return "unknown";
 891     }
 892 }
 893
 894 static char * err_to_char(int err)
 895 {
 896     switch (err) {
 897         case KB_Success:
 898             return "success";
 899         case KB_GeneralError:
 900             return "general error";
 901         case KB_BagNotFound:
 902             return "bag not found";
 903         case KB_BagError:
 904             return "bag error";
 905         case KB_BagNotLoaded:
 906             return "bag not loaded";
 907         case KB_BagExists:
 908             return "bag exists";
 909         case KB_InvalidSession:
 910             return "invalid session";
 911         default:
 912             return "";
 913     }
 914 }
 915
 916 void service_peer_event_handler(xpc_connection_t connection, xpc_object_t event)
 917 {
 918     xpc_type_t type = xpc_get_type(event);
 919
 920     if (type == XPC_TYPE_ERROR) {
 921                 if (event == XPC_ERROR_CONNECTION_INVALID) {
 922         }
 923     } else {
 924         assert(type == XPC_TYPE_DICTIONARY);
 925
 926         int rc = KB_GeneralError;
 927         uint64_t request = 0;
 928         const uint8_t * secret = NULL, * new_secret = NULL;
 929         size_t secret_len = 0, new_secret_len = 0, data_len = 0;
 930         service_context_t * context = NULL;
 931         bool free_context = false;
 932         const void * data;
 933
 934         xpc_object_t reply = xpc_dictionary_create_reply(event);
 935
 936         request = xpc_dictionary_get_uint64(event, SERVICE_XPC_REQUEST);
 937
 938         // For SERVICE_KB_UNLOAD only, allow non-securityd, non-root but
 939         // entitled callers.
 940         if (request == SERVICE_KB_UNLOAD) {
 941             if (!peer_has_entitlement(connection, "com.apple.private.securityd.keybag-unload")) {
 942                 xpc_connection_cancel(connection);
 943                 return;
 944             }
 945         } else {
 946             if (xpc_connection_get_euid(connection) != 0) {
 947                 xpc_connection_cancel(connection);
 948                 return;
 949             }
 950             if (!check_signature(connection)) {
 951                 xpc_connection_cancel(connection);
 952                 return;
 953             }
 954         }
 955
 956         data = xpc_dictionary_get_data(event, SERVICE_XPC_CONTEXT, &data_len);
 957         require_action(data || request == SERVICE_KB_UNLOAD, done, rc = KB_GeneralError);
 958         if (data) {
 959             require(data_len == sizeof(service_context_t), done);
 960             context = (service_context_t*)data;
 961         } else {
 962             audit_token_t audit_token = { 0 };
 963             xpc_connection_get_audit_token(connection, &audit_token);
 964             context = calloc(1, sizeof(service_context_t));
 965             context->s_id = xpc_connection_get_asid(connection);
 966             context->s_uid = xpc_connection_get_euid(connection);
 967             context->procToken = audit_token;
 968             free_context = true;
 969         }
 970
 971         require_action(context->s_id != AU_DEFAUDITSID, done, rc = KB_InvalidSession);
 972         require_action(context->s_uid != AU_DEFAUDITID, done, rc = KB_InvalidSession); // we only want to work in actual user sessions.
 973
 974         switch (request) {
 975             case SERVICE_KB_CREATE:
 976                 //                if (kb_service_has_entitlement(peer, "com.apple.keystore.device")) {
 977                 secret = xpc_dictionary_get_data(event, SERVICE_XPC_SECRET, &secret_len);
 978                 rc = service_kb_create(context, secret, (int)secret_len);
 979                 //                }
 980                 break;
 981             case SERVICE_KB_LOAD:
 982                 rc = service_kb_load(context);
 983                 break;
 984             case SERVICE_KB_UNLOAD:
 985                 rc = service_kb_unload(context);
 986                 break;
 987             case SERVICE_KB_SAVE:
 988                 rc = service_kb_save(context);
 989                 break;
 990             case SERVICE_KB_UNLOCK:
 991                 secret = xpc_dictionary_get_data(event, SERVICE_XPC_SECRET, &secret_len);
 992                 rc = service_kb_unlock(context, secret, (int)secret_len);
 993                 break;
 994             case SERVICE_KB_LOCK:
 995                 rc = service_kb_lock(context);
 996                 break;
 997             case SERVICE_KB_CHANGE_SECRET:
 998                 secret = xpc_dictionary_get_data(event, SERVICE_XPC_SECRET, &secret_len);
 999                 new_secret = xpc_dictionary_get_data(event, SERVICE_XPC_SECRET_NEW, &new_secret_len);
1000                 rc = service_kb_change_secret(context, secret, (int)secret_len, new_secret, (int)new_secret_len);
1001                 break;
1002             case SERVICE_KB_RESET:
1003                 secret = xpc_dictionary_get_data(event, SERVICE_XPC_SECRET, &secret_len);
1004                 rc = service_kb_reset(context, secret, (int)secret_len);
1005                 break;
1006             case SERVICE_KB_IS_LOCKED:
1007                 rc = service_kb_is_locked(context, reply);
1008                 break;
1009             case SERVICE_STASH_GET_KEY:
1010                 rc = service_stash_get_key(context, event, reply);
1011                 break;
1012             case SERVICE_STASH_SET_KEY:
1013                 rc = service_stash_set_key(context, event, reply);
1014                 break;
1015             case SERVICE_STASH_LOAD_KEY:
1016                 rc = service_stash_load_key(context, event, reply);
1017                 break;
1018 #if DEBUG
1019             case SERVICE_STASH_BLOB:
1020                 rc = service_stash_blob(event, reply);
1021                 break;
1022 #endif
1023             default:
1024                 LOG("unknown service type");
1025                 break;
1026         }
1027
1028     done:
1029 #if DEBUG
1030         LOG("selector: %s (%llu), error: %s (%x), sid: %d, suid: %d, pid: %d", sel_to_char(request), request, err_to_char(rc), rc, context ? context->s_id : 0, context ? context->s_uid : 0, context ? get_caller_pid(&context->procToken) : 0);
1031 #else
1032         if (rc != 0) {
1033             syslog(LOG_NOTICE, "selector: %s (%llu), error: %s (%x), sid: %d, suid: %d, pid: %d", sel_to_char(request), request, err_to_char(rc), rc, context ? context->s_id : 0, context ? context->s_uid : 0, context ? get_caller_pid(&context->procToken) : 0);
1034         }
1035 #endif
1036         xpc_dictionary_set_int64(reply, SERVICE_XPC_RC, rc);
1037         xpc_connection_send_message(connection, reply);
1038         xpc_release(reply);
1039         if (free_context) {
1040             free(context);
1041         }
1042     }
1043 }
1044
1045 bool check_signature(xpc_connection_t connection)
1046 {
1047 #if !(DEBUG || RC_BUILDIT_YES)
1048     audit_token_t token;
1049
1050     xpc_connection_get_audit_token(connection, &token);
1051
1052     SecTaskRef task = SecTaskCreateWithAuditToken(NULL, token);
1053     if (task == NULL) {
1054         syslog(LOG_NOTICE, "failed getting SecTaskRef of the client");
1055         return false;
1056     }
1057
1058     uint32_t flags = SecTaskGetCodeSignStatus(task);
1059     /* check if valid and platform binary, but not platform path */
1060     if ((flags & (CS_VALID | CS_PLATFORM_BINARY | CS_PLATFORM_PATH)) != (CS_VALID | CS_PLATFORM_BINARY)) {
1061         syslog(LOG_NOTICE, "client is not a platform binary: %0x08x", flags);
1062         CFRelease(task);
1063         return false;
1064     }
1065
1066     CFStringRef signingIdentity = SecTaskCopySigningIdentifier(task, NULL);
1067     CFRelease(task);
1068     if (signingIdentity == NULL) {
1069         syslog(LOG_NOTICE, "client have no code sign identity");
1070         return false;
1071     }
1072
1073     bool res = CFEqual(signingIdentity, CFSTR("com.apple.securityd"));
1074     CFRelease(signingIdentity);
1075
1076     if (!res)
1077         syslog(LOG_NOTICE, "client is not not securityd");
1078
1079     return res;
1080 #else
1081     return true;
1082 #endif
1083 }
1084
1085 static void register_for_notifications()
1086 {
1087     __block kern_return_t kr;
1088     static mach_port_t mp = MACH_PORT_NULL;
1089
1090     static dispatch_once_t onceToken = 0;
1091     dispatch_once(&onceToken, ^{
1092         kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &mp);
1093         if (kr == KERN_SUCCESS) {
1094             dispatch_source_t mach_src = dispatch_source_create(DISPATCH_SOURCE_TYPE_MACH_RECV, mp, 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
1095             dispatch_source_set_event_handler(mach_src, ^{
1096                 mach_msg_return_t mr;
1097                 uint8_t buf[sizeof(aks_notification_msg_t) + MAX_TRAILER_SIZE] = {};
1098                 aks_notification_msg_t * msg = (aks_notification_msg_t*)buf;
1099                 mr = mach_msg((mach_msg_header_t*)&buf, MACH_RCV_MSG, 0, sizeof(buf), mp, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
1100                 if (mr == MACH_MSG_SUCCESS && msg->hdr.msgh_id == AKS_NOTIFICATION_MSGID) {
1101                     // ignored for now
1102                 } else if (mr == MACH_MSG_SUCCESS && msg->hdr.msgh_id == AKS_NOTIFICATION_WRITE_SYSTEM_KEYBAG) {
1103                     syslog(LOG_NOTICE, "request to update handle %d", msg->handle);
1104                     update_keybag_handle(msg->handle);
1105                 } else {
1106                     syslog(LOG_ERR, "mach_msg error: %x", mr);
1107                 }
1108             });
1109             dispatch_resume(mach_src);
1110         } else {
1111             syslog(LOG_NOTICE, "failed to create notification port");
1112         }
1113
1114     });
1115
1116     kr = aks_register_for_notifications(mp, AKS_NOTIFICATION_WRITE_SYSTEM_KEYBAG);
1117     if (kr == KERN_SUCCESS) {
1118         syslog(LOG_NOTICE, "registered for notifications");
1119     } else {
1120         syslog(LOG_NOTICE, "failed to register for notifications %d", kr);
1121     }
1122 }
1123
1124 int main(int argc, const char * argv[])
1125 {
1126     char * errorbuf;
1127     if (sandbox_init(SECURITYD_SERVICE_NAME, SANDBOX_NAMED, &errorbuf) != 0) {
1128         syslog(LOG_ERR, "sandbox_init failed %s", errorbuf);
1129         sandbox_free_error(errorbuf);
1130 #ifndef DEBUG
1131         abort();
1132 #endif
1133     }
1134
1135     register_for_notifications();
1136
1137     xpc_connection_t listener = xpc_connection_create_mach_service(SECURITYD_SERVICE_NAME, NULL, XPC_CONNECTION_MACH_SERVICE_LISTENER);
1138     xpc_connection_set_event_handler(listener, ^(xpc_object_t peer) {
1139         // It is safe to cast 'peer' to xpc_connection_t assuming
1140         // we have a correct configuration in our launchd.plist.
1141         xpc_connection_set_event_handler(peer, ^(xpc_object_t event) {
1142             vproc_transaction_t transaction = vproc_transaction_begin(NULL);
1143             service_peer_event_handler(peer, event);
1144             vproc_transaction_end(NULL, transaction);
1145         });
1146         xpc_connection_resume(peer);
1147     });
1148     xpc_connection_resume(listener);
1149
1150     dispatch_main();
1151     exit(EXIT_FAILURE);
1152 }
1153