cryptfs.c revision 9dedfd473dc59e0277004e5b917e4eced02c8af5
1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* TO DO: 18 * 1. Perhaps keep several copies of the encrypted key, in case something 19 * goes horribly wrong? 20 * 21 */ 22 23#include <sys/types.h> 24#include <sys/stat.h> 25#include <fcntl.h> 26#include <unistd.h> 27#include <stdio.h> 28#include <sys/ioctl.h> 29#include <linux/dm-ioctl.h> 30#include <libgen.h> 31#include <stdlib.h> 32#include <sys/param.h> 33#include <string.h> 34#include <sys/mount.h> 35#include <openssl/evp.h> 36#include <openssl/sha.h> 37#include <errno.h> 38#include <cutils/android_reboot.h> 39#include <ext4.h> 40#include <linux/kdev_t.h> 41#include <fs_mgr.h> 42#include "cryptfs.h" 43#define LOG_TAG "Cryptfs" 44#include "cutils/android_reboot.h" 45#include "cutils/log.h" 46#include "cutils/properties.h" 47#include "hardware_legacy/power.h" 48#include "VolumeManager.h" 49 50#define DM_CRYPT_BUF_SIZE 4096 51#define DATA_MNT_POINT "/data" 52 53#define HASH_COUNT 2000 54#define KEY_LEN_BYTES 16 55#define IV_LEN_BYTES 16 56 57#define KEY_IN_FOOTER "footer" 58 59#define EXT4_FS 1 60#define FAT_FS 2 61 62#define TABLE_LOAD_RETRIES 10 63 64char *me = "cryptfs"; 65 66static unsigned char saved_master_key[KEY_LEN_BYTES]; 67static char *saved_data_blkdev; 68static char *saved_mount_point; 69static int master_key_saved = 0; 70#define FSTAB_PREFIX "/fstab." 71static char fstab_filename[PROPERTY_VALUE_MAX + sizeof(FSTAB_PREFIX)]; 72 73static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) 74{ 75 memset(io, 0, dataSize); 76 io->data_size = dataSize; 77 io->data_start = sizeof(struct dm_ioctl); 78 io->version[0] = 4; 79 io->version[1] = 0; 80 io->version[2] = 0; 81 io->flags = flags; 82 if (name) { 83 strncpy(io->name, name, sizeof(io->name)); 84 } 85} 86 87static unsigned int get_fs_size(char *dev) 88{ 89 int fd, block_size; 90 struct ext4_super_block sb; 91 off64_t len; 92 93 if ((fd = open(dev, O_RDONLY)) < 0) { 94 SLOGE("Cannot open device to get filesystem size "); 95 return 0; 96 } 97 98 if (lseek64(fd, 1024, SEEK_SET) < 0) { 99 SLOGE("Cannot seek to superblock"); 100 return 0; 101 } 102 103 if (read(fd, &sb, sizeof(sb)) != sizeof(sb)) { 104 SLOGE("Cannot read superblock"); 105 return 0; 106 } 107 108 close(fd); 109 110 block_size = 1024 << sb.s_log_block_size; 111 /* compute length in bytes */ 112 len = ( ((off64_t)sb.s_blocks_count_hi << 32) + sb.s_blocks_count_lo) * block_size; 113 114 /* return length in sectors */ 115 return (unsigned int) (len / 512); 116} 117 118static unsigned int get_blkdev_size(int fd) 119{ 120 unsigned int nr_sec; 121 122 if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { 123 nr_sec = 0; 124 } 125 126 return nr_sec; 127} 128 129/* Get and cache the name of the fstab file so we don't 130 * keep talking over the socket to the property service. 131 */ 132static char *get_fstab_filename(void) 133{ 134 if (fstab_filename[0] == 0) { 135 strcpy(fstab_filename, FSTAB_PREFIX); 136 property_get("ro.hardware", fstab_filename + sizeof(FSTAB_PREFIX) - 1, ""); 137 } 138 139 return fstab_filename; 140} 141 142/* key or salt can be NULL, in which case just skip writing that value. Useful to 143 * update the failed mount count but not change the key. 144 */ 145static int put_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 146 unsigned char *key, unsigned char *salt) 147{ 148 int fd; 149 unsigned int nr_sec, cnt; 150 off64_t off; 151 int rc = -1; 152 char *fname; 153 char key_loc[PROPERTY_VALUE_MAX]; 154 struct stat statbuf; 155 156 fs_mgr_get_crypt_info(get_fstab_filename(), key_loc, 0, sizeof(key_loc)); 157 158 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 159 fname = real_blk_name; 160 if ( (fd = open(fname, O_RDWR)) < 0) { 161 SLOGE("Cannot open real block device %s\n", fname); 162 return -1; 163 } 164 165 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 166 SLOGE("Cannot get size of block device %s\n", fname); 167 goto errout; 168 } 169 170 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 171 * encryption info footer and key, and plenty of bytes to spare for future 172 * growth. 173 */ 174 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 175 176 if (lseek64(fd, off, SEEK_SET) == -1) { 177 SLOGE("Cannot seek to real block device footer\n"); 178 goto errout; 179 } 180 } else if (key_loc[0] == '/') { 181 fname = key_loc; 182 if ( (fd = open(fname, O_RDWR | O_CREAT, 0600)) < 0) { 183 SLOGE("Cannot open footer file %s\n", fname); 184 return -1; 185 } 186 } else { 187 SLOGE("Unexpected value for crypto key location\n"); 188 return -1;; 189 } 190 191 if ((cnt = write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 192 SLOGE("Cannot write real block device footer\n"); 193 goto errout; 194 } 195 196 if (key) { 197 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 198 SLOGE("Keysize of %d bits not supported for real block device %s\n", 199 crypt_ftr->keysize*8, fname); 200 goto errout; 201 } 202 203 if ( (cnt = write(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 204 SLOGE("Cannot write key for real block device %s\n", fname); 205 goto errout; 206 } 207 } 208 209 if (salt) { 210 /* Compute the offset from the last write to the salt */ 211 off = KEY_TO_SALT_PADDING; 212 if (! key) 213 off += crypt_ftr->keysize; 214 215 if (lseek64(fd, off, SEEK_CUR) == -1) { 216 SLOGE("Cannot seek to real block device salt \n"); 217 goto errout; 218 } 219 220 if ( (cnt = write(fd, salt, SALT_LEN)) != SALT_LEN) { 221 SLOGE("Cannot write salt for real block device %s\n", fname); 222 goto errout; 223 } 224 } 225 226 fstat(fd, &statbuf); 227 /* If the keys are kept on a raw block device, do not try to truncate it. */ 228 if (S_ISREG(statbuf.st_mode) && (key_loc[0] == '/')) { 229 if (ftruncate(fd, 0x4000)) { 230 SLOGE("Cannot set footer file size\n", fname); 231 goto errout; 232 } 233 } 234 235 /* Success! */ 236 rc = 0; 237 238errout: 239 close(fd); 240 return rc; 241 242} 243 244static int get_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 245 unsigned char *key, unsigned char *salt) 246{ 247 int fd; 248 unsigned int nr_sec, cnt; 249 off64_t off; 250 int rc = -1; 251 char key_loc[PROPERTY_VALUE_MAX]; 252 char *fname; 253 struct stat statbuf; 254 255 fs_mgr_get_crypt_info(get_fstab_filename(), key_loc, 0, sizeof(key_loc)); 256 257 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 258 fname = real_blk_name; 259 if ( (fd = open(fname, O_RDONLY)) < 0) { 260 SLOGE("Cannot open real block device %s\n", fname); 261 return -1; 262 } 263 264 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 265 SLOGE("Cannot get size of block device %s\n", fname); 266 goto errout; 267 } 268 269 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 270 * encryption info footer and key, and plenty of bytes to spare for future 271 * growth. 272 */ 273 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 274 275 if (lseek64(fd, off, SEEK_SET) == -1) { 276 SLOGE("Cannot seek to real block device footer\n"); 277 goto errout; 278 } 279 } else if (key_loc[0] == '/') { 280 fname = key_loc; 281 if ( (fd = open(fname, O_RDONLY)) < 0) { 282 SLOGE("Cannot open footer file %s\n", fname); 283 return -1; 284 } 285 286 /* Make sure it's 16 Kbytes in length */ 287 fstat(fd, &statbuf); 288 if (S_ISREG(statbuf.st_mode) && (statbuf.st_size != 0x4000)) { 289 SLOGE("footer file %s is not the expected size!\n", fname); 290 goto errout; 291 } 292 } else { 293 SLOGE("Unexpected value for crypto key location\n"); 294 return -1;; 295 } 296 297 if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 298 SLOGE("Cannot read real block device footer\n"); 299 goto errout; 300 } 301 302 if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { 303 SLOGE("Bad magic for real block device %s\n", fname); 304 goto errout; 305 } 306 307 if (crypt_ftr->major_version != 1) { 308 SLOGE("Cannot understand major version %d real block device footer\n", 309 crypt_ftr->major_version); 310 goto errout; 311 } 312 313 if (crypt_ftr->minor_version != 0) { 314 SLOGW("Warning: crypto footer minor version %d, expected 0, continuing...\n", 315 crypt_ftr->minor_version); 316 } 317 318 if (crypt_ftr->ftr_size > sizeof(struct crypt_mnt_ftr)) { 319 /* the footer size is bigger than we expected. 320 * Skip to it's stated end so we can read the key. 321 */ 322 if (lseek(fd, crypt_ftr->ftr_size - sizeof(struct crypt_mnt_ftr), SEEK_CUR) == -1) { 323 SLOGE("Cannot seek to start of key\n"); 324 goto errout; 325 } 326 } 327 328 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 329 SLOGE("Keysize of %d bits not supported for real block device %s\n", 330 crypt_ftr->keysize * 8, fname); 331 goto errout; 332 } 333 334 if ( (cnt = read(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 335 SLOGE("Cannot read key for real block device %s\n", fname); 336 goto errout; 337 } 338 339 if (lseek64(fd, KEY_TO_SALT_PADDING, SEEK_CUR) == -1) { 340 SLOGE("Cannot seek to real block device salt\n"); 341 goto errout; 342 } 343 344 if ( (cnt = read(fd, salt, SALT_LEN)) != SALT_LEN) { 345 SLOGE("Cannot read salt for real block device %s\n", fname); 346 goto errout; 347 } 348 349 /* Success! */ 350 rc = 0; 351 352errout: 353 close(fd); 354 return rc; 355} 356 357/* Convert a binary key of specified length into an ascii hex string equivalent, 358 * without the leading 0x and with null termination 359 */ 360void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, 361 char *master_key_ascii) 362{ 363 unsigned int i, a; 364 unsigned char nibble; 365 366 for (i=0, a=0; i<keysize; i++, a+=2) { 367 /* For each byte, write out two ascii hex digits */ 368 nibble = (master_key[i] >> 4) & 0xf; 369 master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); 370 371 nibble = master_key[i] & 0xf; 372 master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); 373 } 374 375 /* Add the null termination */ 376 master_key_ascii[a] = '\0'; 377 378} 379 380static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, 381 char *real_blk_name, char *crypto_blk_name, const char *name) 382{ 383 char buffer[DM_CRYPT_BUF_SIZE]; 384 char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ 385 char *crypt_params; 386 struct dm_ioctl *io; 387 struct dm_target_spec *tgt; 388 unsigned int minor; 389 int fd; 390 int i; 391 int retval = -1; 392 393 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 394 SLOGE("Cannot open device-mapper\n"); 395 goto errout; 396 } 397 398 io = (struct dm_ioctl *) buffer; 399 400 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 401 if (ioctl(fd, DM_DEV_CREATE, io)) { 402 SLOGE("Cannot create dm-crypt device\n"); 403 goto errout; 404 } 405 406 /* Get the device status, in particular, the name of it's device file */ 407 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 408 if (ioctl(fd, DM_DEV_STATUS, io)) { 409 SLOGE("Cannot retrieve dm-crypt device status\n"); 410 goto errout; 411 } 412 minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); 413 snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); 414 415 /* Load the mapping table for this device */ 416 tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; 417 418 ioctl_init(io, 4096, name, 0); 419 io->target_count = 1; 420 tgt->status = 0; 421 tgt->sector_start = 0; 422 tgt->length = crypt_ftr->fs_size; 423 strcpy(tgt->target_type, "crypt"); 424 425 crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); 426 convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); 427 sprintf(crypt_params, "%s %s 0 %s 0", crypt_ftr->crypto_type_name, 428 master_key_ascii, real_blk_name); 429 crypt_params += strlen(crypt_params) + 1; 430 crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ 431 tgt->next = crypt_params - buffer; 432 433 for (i = 0; i < TABLE_LOAD_RETRIES; i++) { 434 if (! ioctl(fd, DM_TABLE_LOAD, io)) { 435 break; 436 } 437 usleep(500000); 438 } 439 440 if (i == TABLE_LOAD_RETRIES) { 441 SLOGE("Cannot load dm-crypt mapping table.\n"); 442 goto errout; 443 } else if (i) { 444 SLOGI("Took %d tries to load dmcrypt table.\n", i + 1); 445 } 446 447 /* Resume this device to activate it */ 448 ioctl_init(io, 4096, name, 0); 449 450 if (ioctl(fd, DM_DEV_SUSPEND, io)) { 451 SLOGE("Cannot resume the dm-crypt device\n"); 452 goto errout; 453 } 454 455 /* We made it here with no errors. Woot! */ 456 retval = 0; 457 458errout: 459 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 460 461 return retval; 462} 463 464static int delete_crypto_blk_dev(char *name) 465{ 466 int fd; 467 char buffer[DM_CRYPT_BUF_SIZE]; 468 struct dm_ioctl *io; 469 int retval = -1; 470 471 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 472 SLOGE("Cannot open device-mapper\n"); 473 goto errout; 474 } 475 476 io = (struct dm_ioctl *) buffer; 477 478 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 479 if (ioctl(fd, DM_DEV_REMOVE, io)) { 480 SLOGE("Cannot remove dm-crypt device\n"); 481 goto errout; 482 } 483 484 /* We made it here with no errors. Woot! */ 485 retval = 0; 486 487errout: 488 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 489 490 return retval; 491 492} 493 494static void pbkdf2(char *passwd, unsigned char *salt, unsigned char *ikey) 495{ 496 /* Turn the password into a key and IV that can decrypt the master key */ 497 PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN, 498 HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); 499} 500 501static int encrypt_master_key(char *passwd, unsigned char *salt, 502 unsigned char *decrypted_master_key, 503 unsigned char *encrypted_master_key) 504{ 505 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 506 EVP_CIPHER_CTX e_ctx; 507 int encrypted_len, final_len; 508 509 /* Turn the password into a key and IV that can decrypt the master key */ 510 pbkdf2(passwd, salt, ikey); 511 512 /* Initialize the decryption engine */ 513 if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 514 SLOGE("EVP_EncryptInit failed\n"); 515 return -1; 516 } 517 EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ 518 519 /* Encrypt the master key */ 520 if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len, 521 decrypted_master_key, KEY_LEN_BYTES)) { 522 SLOGE("EVP_EncryptUpdate failed\n"); 523 return -1; 524 } 525 if (! EVP_EncryptFinal(&e_ctx, encrypted_master_key + encrypted_len, &final_len)) { 526 SLOGE("EVP_EncryptFinal failed\n"); 527 return -1; 528 } 529 530 if (encrypted_len + final_len != KEY_LEN_BYTES) { 531 SLOGE("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); 532 return -1; 533 } else { 534 return 0; 535 } 536} 537 538static int decrypt_master_key(char *passwd, unsigned char *salt, 539 unsigned char *encrypted_master_key, 540 unsigned char *decrypted_master_key) 541{ 542 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 543 EVP_CIPHER_CTX d_ctx; 544 int decrypted_len, final_len; 545 546 /* Turn the password into a key and IV that can decrypt the master key */ 547 pbkdf2(passwd, salt, ikey); 548 549 /* Initialize the decryption engine */ 550 if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 551 return -1; 552 } 553 EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ 554 /* Decrypt the master key */ 555 if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, 556 encrypted_master_key, KEY_LEN_BYTES)) { 557 return -1; 558 } 559 if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { 560 return -1; 561 } 562 563 if (decrypted_len + final_len != KEY_LEN_BYTES) { 564 return -1; 565 } else { 566 return 0; 567 } 568} 569 570static int create_encrypted_random_key(char *passwd, unsigned char *master_key, unsigned char *salt) 571{ 572 int fd; 573 unsigned char key_buf[KEY_LEN_BYTES]; 574 EVP_CIPHER_CTX e_ctx; 575 int encrypted_len, final_len; 576 577 /* Get some random bits for a key */ 578 fd = open("/dev/urandom", O_RDONLY); 579 read(fd, key_buf, sizeof(key_buf)); 580 read(fd, salt, SALT_LEN); 581 close(fd); 582 583 /* Now encrypt it with the password */ 584 return encrypt_master_key(passwd, salt, key_buf, master_key); 585} 586 587static int wait_and_unmount(char *mountpoint) 588{ 589 int i, rc; 590#define WAIT_UNMOUNT_COUNT 20 591 592 /* Now umount the tmpfs filesystem */ 593 for (i=0; i<WAIT_UNMOUNT_COUNT; i++) { 594 if (umount(mountpoint)) { 595 if (errno == EINVAL) { 596 /* EINVAL is returned if the directory is not a mountpoint, 597 * i.e. there is no filesystem mounted there. So just get out. 598 */ 599 break; 600 } 601 sleep(1); 602 i++; 603 } else { 604 break; 605 } 606 } 607 608 if (i < WAIT_UNMOUNT_COUNT) { 609 SLOGD("unmounting %s succeeded\n", mountpoint); 610 rc = 0; 611 } else { 612 SLOGE("unmounting %s failed\n", mountpoint); 613 rc = -1; 614 } 615 616 return rc; 617} 618 619#define DATA_PREP_TIMEOUT 100 620static int prep_data_fs(void) 621{ 622 int i; 623 624 /* Do the prep of the /data filesystem */ 625 property_set("vold.post_fs_data_done", "0"); 626 property_set("vold.decrypt", "trigger_post_fs_data"); 627 SLOGD("Just triggered post_fs_data\n"); 628 629 /* Wait a max of 25 seconds, hopefully it takes much less */ 630 for (i=0; i<DATA_PREP_TIMEOUT; i++) { 631 char p[PROPERTY_VALUE_MAX]; 632 633 property_get("vold.post_fs_data_done", p, "0"); 634 if (*p == '1') { 635 break; 636 } else { 637 usleep(250000); 638 } 639 } 640 if (i == DATA_PREP_TIMEOUT) { 641 /* Ugh, we failed to prep /data in time. Bail. */ 642 return -1; 643 } else { 644 SLOGD("post_fs_data done\n"); 645 return 0; 646 } 647} 648 649int cryptfs_restart(void) 650{ 651 char fs_type[32]; 652 char real_blkdev[MAXPATHLEN]; 653 char crypto_blkdev[MAXPATHLEN]; 654 char fs_options[256]; 655 unsigned long mnt_flags; 656 struct stat statbuf; 657 int rc = -1, i; 658 static int restart_successful = 0; 659 660 /* Validate that it's OK to call this routine */ 661 if (! master_key_saved) { 662 SLOGE("Encrypted filesystem not validated, aborting"); 663 return -1; 664 } 665 666 if (restart_successful) { 667 SLOGE("System already restarted with encrypted disk, aborting"); 668 return -1; 669 } 670 671 /* Here is where we shut down the framework. The init scripts 672 * start all services in one of three classes: core, main or late_start. 673 * On boot, we start core and main. Now, we stop main, but not core, 674 * as core includes vold and a few other really important things that 675 * we need to keep running. Once main has stopped, we should be able 676 * to umount the tmpfs /data, then mount the encrypted /data. 677 * We then restart the class main, and also the class late_start. 678 * At the moment, I've only put a few things in late_start that I know 679 * are not needed to bring up the framework, and that also cause problems 680 * with unmounting the tmpfs /data, but I hope to add add more services 681 * to the late_start class as we optimize this to decrease the delay 682 * till the user is asked for the password to the filesystem. 683 */ 684 685 /* The init files are setup to stop the class main when vold.decrypt is 686 * set to trigger_reset_main. 687 */ 688 property_set("vold.decrypt", "trigger_reset_main"); 689 SLOGD("Just asked init to shut down class main\n"); 690 691 /* Give everything a chance to shutdown */ 692 sleep(1); 693 694 /* Now that the framework is shutdown, we should be able to umount() 695 * the tmpfs filesystem, and mount the real one. 696 */ 697 698 property_get("ro.crypto.fs_crypto_blkdev", crypto_blkdev, ""); 699 if (strlen(crypto_blkdev) == 0) { 700 SLOGE("fs_crypto_blkdev not set\n"); 701 return -1; 702 } 703 704 if (! (rc = wait_and_unmount(DATA_MNT_POINT)) ) { 705 /* If that succeeded, then mount the decrypted filesystem */ 706 fs_mgr_do_mount(get_fstab_filename(), DATA_MNT_POINT, crypto_blkdev, 0); 707 708 property_set("vold.decrypt", "trigger_load_persist_props"); 709 /* Create necessary paths on /data */ 710 if (prep_data_fs()) { 711 return -1; 712 } 713 714 /* startup service classes main and late_start */ 715 property_set("vold.decrypt", "trigger_restart_framework"); 716 SLOGD("Just triggered restart_framework\n"); 717 718 /* Give it a few moments to get started */ 719 sleep(1); 720 } 721 722 if (rc == 0) { 723 restart_successful = 1; 724 } 725 726 return rc; 727} 728 729static int do_crypto_complete(char *mount_point) 730{ 731 struct crypt_mnt_ftr crypt_ftr; 732 unsigned char encrypted_master_key[32]; 733 unsigned char salt[SALT_LEN]; 734 char real_blkdev[MAXPATHLEN]; 735 char encrypted_state[PROPERTY_VALUE_MAX]; 736 char key_loc[PROPERTY_VALUE_MAX]; 737 738 property_get("ro.crypto.state", encrypted_state, ""); 739 if (strcmp(encrypted_state, "encrypted") ) { 740 SLOGE("not running with encryption, aborting"); 741 return 1; 742 } 743 744 fs_mgr_get_crypt_info(get_fstab_filename(), 0, real_blkdev, sizeof(real_blkdev)); 745 746 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 747 fs_mgr_get_crypt_info(get_fstab_filename(), key_loc, 0, sizeof(key_loc)); 748 749 /* 750 * Only report this error if key_loc is a file and it exists. 751 * If the device was never encrypted, and /data is not mountable for 752 * some reason, returning 1 should prevent the UI from presenting the 753 * a "enter password" screen, or worse, a "press button to wipe the 754 * device" screen. 755 */ 756 if ((key_loc[0] == '/') && (access("key_loc", F_OK) == -1)) { 757 SLOGE("master key file does not exist, aborting"); 758 return 1; 759 } else { 760 SLOGE("Error getting crypt footer and key\n"); 761 return -1; 762 } 763 } 764 765 if (crypt_ftr.flags & CRYPT_ENCRYPTION_IN_PROGRESS) { 766 SLOGE("Encryption process didn't finish successfully\n"); 767 return -2; /* -2 is the clue to the UI that there is no usable data on the disk, 768 * and give the user an option to wipe the disk */ 769 } 770 771 /* We passed the test! We shall diminish, and return to the west */ 772 return 0; 773} 774 775static int test_mount_encrypted_fs(char *passwd, char *mount_point, char *label) 776{ 777 struct crypt_mnt_ftr crypt_ftr; 778 /* Allocate enough space for a 256 bit key, but we may use less */ 779 unsigned char encrypted_master_key[32], decrypted_master_key[32]; 780 unsigned char salt[SALT_LEN]; 781 char crypto_blkdev[MAXPATHLEN]; 782 char real_blkdev[MAXPATHLEN]; 783 char tmp_mount_point[64]; 784 unsigned int orig_failed_decrypt_count; 785 char encrypted_state[PROPERTY_VALUE_MAX]; 786 int rc; 787 788 property_get("ro.crypto.state", encrypted_state, ""); 789 if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) { 790 SLOGE("encrypted fs already validated or not running with encryption, aborting"); 791 return -1; 792 } 793 794 fs_mgr_get_crypt_info(get_fstab_filename(), 0, real_blkdev, sizeof(real_blkdev)); 795 796 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 797 SLOGE("Error getting crypt footer and key\n"); 798 return -1; 799 } 800 801 SLOGD("crypt_ftr->fs_size = %lld\n", crypt_ftr.fs_size); 802 orig_failed_decrypt_count = crypt_ftr.failed_decrypt_count; 803 804 if (! (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { 805 decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); 806 } 807 808 if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, 809 real_blkdev, crypto_blkdev, label)) { 810 SLOGE("Error creating decrypted block device\n"); 811 return -1; 812 } 813 814 /* If init detects an encrypted filesystme, it writes a file for each such 815 * encrypted fs into the tmpfs /data filesystem, and then the framework finds those 816 * files and passes that data to me */ 817 /* Create a tmp mount point to try mounting the decryptd fs 818 * Since we're here, the mount_point should be a tmpfs filesystem, so make 819 * a directory in it to test mount the decrypted filesystem. 820 */ 821 sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); 822 mkdir(tmp_mount_point, 0755); 823 if (fs_mgr_do_mount(get_fstab_filename(), DATA_MNT_POINT, crypto_blkdev, tmp_mount_point)) { 824 SLOGE("Error temp mounting decrypted block device\n"); 825 delete_crypto_blk_dev(label); 826 crypt_ftr.failed_decrypt_count++; 827 } else { 828 /* Success, so just umount and we'll mount it properly when we restart 829 * the framework. 830 */ 831 umount(tmp_mount_point); 832 crypt_ftr.failed_decrypt_count = 0; 833 } 834 835 if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) { 836 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 837 } 838 839 if (crypt_ftr.failed_decrypt_count) { 840 /* We failed to mount the device, so return an error */ 841 rc = crypt_ftr.failed_decrypt_count; 842 843 } else { 844 /* Woot! Success! Save the name of the crypto block device 845 * so we can mount it when restarting the framework. 846 */ 847 property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); 848 849 /* Also save a the master key so we can reencrypted the key 850 * the key when we want to change the password on it. 851 */ 852 memcpy(saved_master_key, decrypted_master_key, KEY_LEN_BYTES); 853 saved_data_blkdev = strdup(real_blkdev); 854 saved_mount_point = strdup(mount_point); 855 master_key_saved = 1; 856 rc = 0; 857 } 858 859 return rc; 860} 861 862/* Called by vold when it wants to undo the crypto mapping of a volume it 863 * manages. This is usually in response to a factory reset, when we want 864 * to undo the crypto mapping so the volume is formatted in the clear. 865 */ 866int cryptfs_revert_volume(const char *label) 867{ 868 return delete_crypto_blk_dev((char *)label); 869} 870 871/* 872 * Called by vold when it's asked to mount an encrypted, nonremovable volume. 873 * Setup a dm-crypt mapping, use the saved master key from 874 * setting up the /data mapping, and return the new device path. 875 */ 876int cryptfs_setup_volume(const char *label, int major, int minor, 877 char *crypto_sys_path, unsigned int max_path, 878 int *new_major, int *new_minor) 879{ 880 char real_blkdev[MAXPATHLEN], crypto_blkdev[MAXPATHLEN]; 881 struct crypt_mnt_ftr sd_crypt_ftr; 882 unsigned char key[32], salt[32]; 883 struct stat statbuf; 884 int nr_sec, fd; 885 886 sprintf(real_blkdev, "/dev/block/vold/%d:%d", major, minor); 887 888 /* Just want the footer, but gotta get it all */ 889 get_crypt_ftr_and_key(saved_data_blkdev, &sd_crypt_ftr, key, salt); 890 891 /* Update the fs_size field to be the size of the volume */ 892 fd = open(real_blkdev, O_RDONLY); 893 nr_sec = get_blkdev_size(fd); 894 close(fd); 895 if (nr_sec == 0) { 896 SLOGE("Cannot get size of volume %s\n", real_blkdev); 897 return -1; 898 } 899 900 sd_crypt_ftr.fs_size = nr_sec; 901 create_crypto_blk_dev(&sd_crypt_ftr, saved_master_key, real_blkdev, 902 crypto_blkdev, label); 903 904 stat(crypto_blkdev, &statbuf); 905 *new_major = MAJOR(statbuf.st_rdev); 906 *new_minor = MINOR(statbuf.st_rdev); 907 908 /* Create path to sys entry for this block device */ 909 snprintf(crypto_sys_path, max_path, "/devices/virtual/block/%s", strrchr(crypto_blkdev, '/')+1); 910 911 return 0; 912} 913 914int cryptfs_crypto_complete(void) 915{ 916 return do_crypto_complete("/data"); 917} 918 919int cryptfs_check_passwd(char *passwd) 920{ 921 int rc = -1; 922 923 rc = test_mount_encrypted_fs(passwd, DATA_MNT_POINT, "userdata"); 924 925 return rc; 926} 927 928int cryptfs_verify_passwd(char *passwd) 929{ 930 struct crypt_mnt_ftr crypt_ftr; 931 /* Allocate enough space for a 256 bit key, but we may use less */ 932 unsigned char encrypted_master_key[32], decrypted_master_key[32]; 933 unsigned char salt[SALT_LEN]; 934 char real_blkdev[MAXPATHLEN]; 935 char encrypted_state[PROPERTY_VALUE_MAX]; 936 int rc; 937 938 property_get("ro.crypto.state", encrypted_state, ""); 939 if (strcmp(encrypted_state, "encrypted") ) { 940 SLOGE("device not encrypted, aborting"); 941 return -2; 942 } 943 944 if (!master_key_saved) { 945 SLOGE("encrypted fs not yet mounted, aborting"); 946 return -1; 947 } 948 949 if (!saved_mount_point) { 950 SLOGE("encrypted fs failed to save mount point, aborting"); 951 return -1; 952 } 953 954 fs_mgr_get_crypt_info(get_fstab_filename(), 0, real_blkdev, sizeof(real_blkdev)); 955 956 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 957 SLOGE("Error getting crypt footer and key\n"); 958 return -1; 959 } 960 961 if (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) { 962 /* If the device has no password, then just say the password is valid */ 963 rc = 0; 964 } else { 965 decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); 966 if (!memcmp(decrypted_master_key, saved_master_key, crypt_ftr.keysize)) { 967 /* They match, the password is correct */ 968 rc = 0; 969 } else { 970 /* If incorrect, sleep for a bit to prevent dictionary attacks */ 971 sleep(1); 972 rc = 1; 973 } 974 } 975 976 return rc; 977} 978 979/* Initialize a crypt_mnt_ftr structure. The keysize is 980 * defaulted to 16 bytes, and the filesystem size to 0. 981 * Presumably, at a minimum, the caller will update the 982 * filesystem size and crypto_type_name after calling this function. 983 */ 984static void cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) 985{ 986 ftr->magic = CRYPT_MNT_MAGIC; 987 ftr->major_version = 1; 988 ftr->minor_version = 0; 989 ftr->ftr_size = sizeof(struct crypt_mnt_ftr); 990 ftr->flags = 0; 991 ftr->keysize = KEY_LEN_BYTES; 992 ftr->spare1 = 0; 993 ftr->fs_size = 0; 994 ftr->failed_decrypt_count = 0; 995 ftr->crypto_type_name[0] = '\0'; 996} 997 998static int cryptfs_enable_wipe(char *crypto_blkdev, off64_t size, int type) 999{ 1000 char cmdline[256]; 1001 int rc = -1; 1002 1003 if (type == EXT4_FS) { 1004 snprintf(cmdline, sizeof(cmdline), "/system/bin/make_ext4fs -a /data -l %lld %s", 1005 size * 512, crypto_blkdev); 1006 SLOGI("Making empty filesystem with command %s\n", cmdline); 1007 } else if (type== FAT_FS) { 1008 snprintf(cmdline, sizeof(cmdline), "/system/bin/newfs_msdos -F 32 -O android -c 8 -s %lld %s", 1009 size, crypto_blkdev); 1010 SLOGI("Making empty filesystem with command %s\n", cmdline); 1011 } else { 1012 SLOGE("cryptfs_enable_wipe(): unknown filesystem type %d\n", type); 1013 return -1; 1014 } 1015 1016 if (system(cmdline)) { 1017 SLOGE("Error creating empty filesystem on %s\n", crypto_blkdev); 1018 } else { 1019 SLOGD("Successfully created empty filesystem on %s\n", crypto_blkdev); 1020 rc = 0; 1021 } 1022 1023 return rc; 1024} 1025 1026static inline int unix_read(int fd, void* buff, int len) 1027{ 1028 int ret; 1029 do { ret = read(fd, buff, len); } while (ret < 0 && errno == EINTR); 1030 return ret; 1031} 1032 1033static inline int unix_write(int fd, const void* buff, int len) 1034{ 1035 int ret; 1036 do { ret = write(fd, buff, len); } while (ret < 0 && errno == EINTR); 1037 return ret; 1038} 1039 1040#define CRYPT_INPLACE_BUFSIZE 4096 1041#define CRYPT_SECTORS_PER_BUFSIZE (CRYPT_INPLACE_BUFSIZE / 512) 1042static int cryptfs_enable_inplace(char *crypto_blkdev, char *real_blkdev, off64_t size, 1043 off64_t *size_already_done, off64_t tot_size) 1044{ 1045 int realfd, cryptofd; 1046 char *buf[CRYPT_INPLACE_BUFSIZE]; 1047 int rc = -1; 1048 off64_t numblocks, i, remainder; 1049 off64_t one_pct, cur_pct, new_pct; 1050 off64_t blocks_already_done, tot_numblocks; 1051 1052 if ( (realfd = open(real_blkdev, O_RDONLY)) < 0) { 1053 SLOGE("Error opening real_blkdev %s for inplace encrypt\n", real_blkdev); 1054 return -1; 1055 } 1056 1057 if ( (cryptofd = open(crypto_blkdev, O_WRONLY)) < 0) { 1058 SLOGE("Error opening crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1059 close(realfd); 1060 return -1; 1061 } 1062 1063 /* This is pretty much a simple loop of reading 4K, and writing 4K. 1064 * The size passed in is the number of 512 byte sectors in the filesystem. 1065 * So compute the number of whole 4K blocks we should read/write, 1066 * and the remainder. 1067 */ 1068 numblocks = size / CRYPT_SECTORS_PER_BUFSIZE; 1069 remainder = size % CRYPT_SECTORS_PER_BUFSIZE; 1070 tot_numblocks = tot_size / CRYPT_SECTORS_PER_BUFSIZE; 1071 blocks_already_done = *size_already_done / CRYPT_SECTORS_PER_BUFSIZE; 1072 1073 SLOGE("Encrypting filesystem in place..."); 1074 1075 one_pct = tot_numblocks / 100; 1076 cur_pct = 0; 1077 /* process the majority of the filesystem in blocks */ 1078 for (i=0; i<numblocks; i++) { 1079 new_pct = (i + blocks_already_done) / one_pct; 1080 if (new_pct > cur_pct) { 1081 char buf[8]; 1082 1083 cur_pct = new_pct; 1084 snprintf(buf, sizeof(buf), "%lld", cur_pct); 1085 property_set("vold.encrypt_progress", buf); 1086 } 1087 if (unix_read(realfd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 1088 SLOGE("Error reading real_blkdev %s for inplace encrypt\n", crypto_blkdev); 1089 goto errout; 1090 } 1091 if (unix_write(cryptofd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 1092 SLOGE("Error writing crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1093 goto errout; 1094 } 1095 } 1096 1097 /* Do any remaining sectors */ 1098 for (i=0; i<remainder; i++) { 1099 if (unix_read(realfd, buf, 512) <= 0) { 1100 SLOGE("Error reading rival sectors from real_blkdev %s for inplace encrypt\n", crypto_blkdev); 1101 goto errout; 1102 } 1103 if (unix_write(cryptofd, buf, 512) <= 0) { 1104 SLOGE("Error writing final sectors to crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1105 goto errout; 1106 } 1107 } 1108 1109 *size_already_done += size; 1110 rc = 0; 1111 1112errout: 1113 close(realfd); 1114 close(cryptofd); 1115 1116 return rc; 1117} 1118 1119#define CRYPTO_ENABLE_WIPE 1 1120#define CRYPTO_ENABLE_INPLACE 2 1121 1122#define FRAMEWORK_BOOT_WAIT 60 1123 1124static inline int should_encrypt(struct volume_info *volume) 1125{ 1126 return (volume->flags & (VOL_ENCRYPTABLE | VOL_NONREMOVABLE)) == 1127 (VOL_ENCRYPTABLE | VOL_NONREMOVABLE); 1128} 1129 1130int cryptfs_enable(char *howarg, char *passwd) 1131{ 1132 int how = 0; 1133 char crypto_blkdev[MAXPATHLEN], real_blkdev[MAXPATHLEN], sd_crypto_blkdev[MAXPATHLEN]; 1134 unsigned long nr_sec; 1135 unsigned char master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 1136 unsigned char salt[SALT_LEN]; 1137 int rc=-1, fd, i, ret; 1138 struct crypt_mnt_ftr crypt_ftr, sd_crypt_ftr;; 1139 char tmpfs_options[PROPERTY_VALUE_MAX]; 1140 char encrypted_state[PROPERTY_VALUE_MAX]; 1141 char lockid[32] = { 0 }; 1142 char key_loc[PROPERTY_VALUE_MAX]; 1143 char fuse_sdcard[PROPERTY_VALUE_MAX]; 1144 char *sd_mnt_point; 1145 char sd_blk_dev[256] = { 0 }; 1146 int num_vols; 1147 struct volume_info *vol_list = 0; 1148 off64_t cur_encryption_done=0, tot_encryption_size=0; 1149 1150 property_get("ro.crypto.state", encrypted_state, ""); 1151 if (strcmp(encrypted_state, "unencrypted")) { 1152 SLOGE("Device is already running encrypted, aborting"); 1153 goto error_unencrypted; 1154 } 1155 1156 fs_mgr_get_crypt_info(get_fstab_filename(), key_loc, 0, sizeof(key_loc)); 1157 1158 if (!strcmp(howarg, "wipe")) { 1159 how = CRYPTO_ENABLE_WIPE; 1160 } else if (! strcmp(howarg, "inplace")) { 1161 how = CRYPTO_ENABLE_INPLACE; 1162 } else { 1163 /* Shouldn't happen, as CommandListener vets the args */ 1164 goto error_unencrypted; 1165 } 1166 1167 fs_mgr_get_crypt_info(get_fstab_filename(), 0, real_blkdev, sizeof(real_blkdev)); 1168 1169 /* Get the size of the real block device */ 1170 fd = open(real_blkdev, O_RDONLY); 1171 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 1172 SLOGE("Cannot get size of block device %s\n", real_blkdev); 1173 goto error_unencrypted; 1174 } 1175 close(fd); 1176 1177 /* If doing inplace encryption, make sure the orig fs doesn't include the crypto footer */ 1178 if ((how == CRYPTO_ENABLE_INPLACE) && (!strcmp(key_loc, KEY_IN_FOOTER))) { 1179 unsigned int fs_size_sec, max_fs_size_sec; 1180 1181 fs_size_sec = get_fs_size(real_blkdev); 1182 max_fs_size_sec = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 1183 1184 if (fs_size_sec > max_fs_size_sec) { 1185 SLOGE("Orig filesystem overlaps crypto footer region. Cannot encrypt in place."); 1186 goto error_unencrypted; 1187 } 1188 } 1189 1190 /* Get a wakelock as this may take a while, and we don't want the 1191 * device to sleep on us. We'll grab a partial wakelock, and if the UI 1192 * wants to keep the screen on, it can grab a full wakelock. 1193 */ 1194 snprintf(lockid, sizeof(lockid), "enablecrypto%d", (int) getpid()); 1195 acquire_wake_lock(PARTIAL_WAKE_LOCK, lockid); 1196 1197 /* Get the sdcard mount point */ 1198 sd_mnt_point = getenv("EMULATED_STORAGE_SOURCE"); 1199 if (!sd_mnt_point) { 1200 sd_mnt_point = getenv("EXTERNAL_STORAGE"); 1201 } 1202 if (!sd_mnt_point) { 1203 sd_mnt_point = "/mnt/sdcard"; 1204 } 1205 1206 num_vols=vold_getNumDirectVolumes(); 1207 vol_list = malloc(sizeof(struct volume_info) * num_vols); 1208 vold_getDirectVolumeList(vol_list); 1209 1210 for (i=0; i<num_vols; i++) { 1211 if (should_encrypt(&vol_list[i])) { 1212 fd = open(vol_list[i].blk_dev, O_RDONLY); 1213 if ( (vol_list[i].size = get_blkdev_size(fd)) == 0) { 1214 SLOGE("Cannot get size of block device %s\n", vol_list[i].blk_dev); 1215 goto error_unencrypted; 1216 } 1217 close(fd); 1218 1219 ret=vold_disableVol(vol_list[i].label); 1220 if ((ret < 0) && (ret != UNMOUNT_NOT_MOUNTED_ERR)) { 1221 /* -2 is returned when the device exists but is not currently mounted. 1222 * ignore the error and continue. */ 1223 SLOGE("Failed to unmount volume %s\n", vol_list[i].label); 1224 goto error_unencrypted; 1225 } 1226 } 1227 } 1228 1229 /* The init files are setup to stop the class main and late start when 1230 * vold sets trigger_shutdown_framework. 1231 */ 1232 property_set("vold.decrypt", "trigger_shutdown_framework"); 1233 SLOGD("Just asked init to shut down class main\n"); 1234 1235 if (vold_unmountAllAsecs()) { 1236 /* Just report the error. If any are left mounted, 1237 * umounting /data below will fail and handle the error. 1238 */ 1239 SLOGE("Error unmounting internal asecs"); 1240 } 1241 1242 property_get("ro.crypto.fuse_sdcard", fuse_sdcard, ""); 1243 if (!strcmp(fuse_sdcard, "true")) { 1244 /* This is a device using the fuse layer to emulate the sdcard semantics 1245 * on top of the userdata partition. vold does not manage it, it is managed 1246 * by the sdcard service. The sdcard service was killed by the property trigger 1247 * above, so just unmount it now. We must do this _AFTER_ killing the framework, 1248 * unlike the case for vold managed devices above. 1249 */ 1250 if (wait_and_unmount(sd_mnt_point)) { 1251 goto error_shutting_down; 1252 } 1253 } 1254 1255 /* Now unmount the /data partition. */ 1256 if (wait_and_unmount(DATA_MNT_POINT)) { 1257 goto error_shutting_down; 1258 } 1259 1260 /* Do extra work for a better UX when doing the long inplace encryption */ 1261 if (how == CRYPTO_ENABLE_INPLACE) { 1262 /* Now that /data is unmounted, we need to mount a tmpfs 1263 * /data, set a property saying we're doing inplace encryption, 1264 * and restart the framework. 1265 */ 1266 if (fs_mgr_do_tmpfs_mount(DATA_MNT_POINT)) { 1267 goto error_shutting_down; 1268 } 1269 /* Tells the framework that inplace encryption is starting */ 1270 property_set("vold.encrypt_progress", "0"); 1271 1272 /* restart the framework. */ 1273 /* Create necessary paths on /data */ 1274 if (prep_data_fs()) { 1275 goto error_shutting_down; 1276 } 1277 1278 /* startup service classes main and late_start */ 1279 property_set("vold.decrypt", "trigger_restart_min_framework"); 1280 SLOGD("Just triggered restart_min_framework\n"); 1281 1282 /* OK, the framework is restarted and will soon be showing a 1283 * progress bar. Time to setup an encrypted mapping, and 1284 * either write a new filesystem, or encrypt in place updating 1285 * the progress bar as we work. 1286 */ 1287 } 1288 1289 /* Start the actual work of making an encrypted filesystem */ 1290 /* Initialize a crypt_mnt_ftr for the partition */ 1291 cryptfs_init_crypt_mnt_ftr(&crypt_ftr); 1292 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 1293 crypt_ftr.fs_size = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 1294 } else { 1295 crypt_ftr.fs_size = nr_sec; 1296 } 1297 crypt_ftr.flags |= CRYPT_ENCRYPTION_IN_PROGRESS; 1298 strcpy((char *)crypt_ftr.crypto_type_name, "aes-cbc-essiv:sha256"); 1299 1300 /* Make an encrypted master key */ 1301 if (create_encrypted_random_key(passwd, master_key, salt)) { 1302 SLOGE("Cannot create encrypted master key\n"); 1303 goto error_unencrypted; 1304 } 1305 1306 /* Write the key to the end of the partition */ 1307 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, master_key, salt); 1308 1309 decrypt_master_key(passwd, salt, master_key, decrypted_master_key); 1310 create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, real_blkdev, crypto_blkdev, 1311 "userdata"); 1312 1313 /* The size of the userdata partition, and add in the vold volumes below */ 1314 tot_encryption_size = crypt_ftr.fs_size; 1315 1316 /* setup crypto mapping for all encryptable volumes handled by vold */ 1317 for (i=0; i<num_vols; i++) { 1318 if (should_encrypt(&vol_list[i])) { 1319 vol_list[i].crypt_ftr = crypt_ftr; /* gotta love struct assign */ 1320 vol_list[i].crypt_ftr.fs_size = vol_list[i].size; 1321 create_crypto_blk_dev(&vol_list[i].crypt_ftr, decrypted_master_key, 1322 vol_list[i].blk_dev, vol_list[i].crypto_blkdev, 1323 vol_list[i].label); 1324 tot_encryption_size += vol_list[i].size; 1325 } 1326 } 1327 1328 if (how == CRYPTO_ENABLE_WIPE) { 1329 rc = cryptfs_enable_wipe(crypto_blkdev, crypt_ftr.fs_size, EXT4_FS); 1330 /* Encrypt all encryptable volumes handled by vold */ 1331 if (!rc) { 1332 for (i=0; i<num_vols; i++) { 1333 if (should_encrypt(&vol_list[i])) { 1334 rc = cryptfs_enable_wipe(vol_list[i].crypto_blkdev, 1335 vol_list[i].crypt_ftr.fs_size, FAT_FS); 1336 } 1337 } 1338 } 1339 } else if (how == CRYPTO_ENABLE_INPLACE) { 1340 rc = cryptfs_enable_inplace(crypto_blkdev, real_blkdev, crypt_ftr.fs_size, 1341 &cur_encryption_done, tot_encryption_size); 1342 /* Encrypt all encryptable volumes handled by vold */ 1343 if (!rc) { 1344 for (i=0; i<num_vols; i++) { 1345 if (should_encrypt(&vol_list[i])) { 1346 rc = cryptfs_enable_inplace(vol_list[i].crypto_blkdev, 1347 vol_list[i].blk_dev, 1348 vol_list[i].crypt_ftr.fs_size, 1349 &cur_encryption_done, tot_encryption_size); 1350 } 1351 } 1352 } 1353 if (!rc) { 1354 /* The inplace routine never actually sets the progress to 100% 1355 * due to the round down nature of integer division, so set it here */ 1356 property_set("vold.encrypt_progress", "100"); 1357 } 1358 } else { 1359 /* Shouldn't happen */ 1360 SLOGE("cryptfs_enable: internal error, unknown option\n"); 1361 goto error_unencrypted; 1362 } 1363 1364 /* Undo the dm-crypt mapping whether we succeed or not */ 1365 delete_crypto_blk_dev("userdata"); 1366 for (i=0; i<num_vols; i++) { 1367 if (should_encrypt(&vol_list[i])) { 1368 delete_crypto_blk_dev(vol_list[i].label); 1369 } 1370 } 1371 1372 free(vol_list); 1373 1374 if (! rc) { 1375 /* Success */ 1376 1377 /* Clear the encryption in progres flag in the footer */ 1378 crypt_ftr.flags &= ~CRYPT_ENCRYPTION_IN_PROGRESS; 1379 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 1380 1381 sleep(2); /* Give the UI a chance to show 100% progress */ 1382 android_reboot(ANDROID_RB_RESTART, 0, 0); 1383 } else { 1384 char value[PROPERTY_VALUE_MAX]; 1385 1386 property_get("ro.vold.wipe_on_crypt_fail", value, "0"); 1387 if (!strcmp(value, "1")) { 1388 /* wipe data if encryption failed */ 1389 SLOGE("encryption failed - rebooting into recovery to wipe data\n"); 1390 mkdir("/cache/recovery", 0700); 1391 int fd = open("/cache/recovery/command", O_RDWR|O_CREAT|O_TRUNC, 0600); 1392 if (fd >= 0) { 1393 write(fd, "--wipe_data", strlen("--wipe_data") + 1); 1394 close(fd); 1395 } else { 1396 SLOGE("could not open /cache/recovery/command\n"); 1397 } 1398 android_reboot(ANDROID_RB_RESTART2, 0, "recovery"); 1399 } else { 1400 /* set property to trigger dialog */ 1401 property_set("vold.encrypt_progress", "error_partially_encrypted"); 1402 release_wake_lock(lockid); 1403 } 1404 return -1; 1405 } 1406 1407 /* hrm, the encrypt step claims success, but the reboot failed. 1408 * This should not happen. 1409 * Set the property and return. Hope the framework can deal with it. 1410 */ 1411 property_set("vold.encrypt_progress", "error_reboot_failed"); 1412 release_wake_lock(lockid); 1413 return rc; 1414 1415error_unencrypted: 1416 free(vol_list); 1417 property_set("vold.encrypt_progress", "error_not_encrypted"); 1418 if (lockid[0]) { 1419 release_wake_lock(lockid); 1420 } 1421 return -1; 1422 1423error_shutting_down: 1424 /* we failed, and have not encrypted anthing, so the users's data is still intact, 1425 * but the framework is stopped and not restarted to show the error, so it's up to 1426 * vold to restart the system. 1427 */ 1428 SLOGE("Error enabling encryption after framework is shutdown, no data changed, restarting system"); 1429 android_reboot(ANDROID_RB_RESTART, 0, 0); 1430 1431 /* shouldn't get here */ 1432 property_set("vold.encrypt_progress", "error_shutting_down"); 1433 free(vol_list); 1434 if (lockid[0]) { 1435 release_wake_lock(lockid); 1436 } 1437 return -1; 1438} 1439 1440int cryptfs_changepw(char *newpw) 1441{ 1442 struct crypt_mnt_ftr crypt_ftr; 1443 unsigned char encrypted_master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 1444 unsigned char salt[SALT_LEN]; 1445 char real_blkdev[MAXPATHLEN]; 1446 1447 /* This is only allowed after we've successfully decrypted the master key */ 1448 if (! master_key_saved) { 1449 SLOGE("Key not saved, aborting"); 1450 return -1; 1451 } 1452 1453 fs_mgr_get_crypt_info(get_fstab_filename(), 0, real_blkdev, sizeof(real_blkdev)); 1454 if (strlen(real_blkdev) == 0) { 1455 SLOGE("Can't find real blkdev"); 1456 return -1; 1457 } 1458 1459 /* get key */ 1460 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 1461 SLOGE("Error getting crypt footer and key"); 1462 return -1; 1463 } 1464 1465 encrypt_master_key(newpw, salt, saved_master_key, encrypted_master_key); 1466 1467 /* save the key */ 1468 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt); 1469 1470 return 0; 1471} 1472