cryptfs.c revision d02a47239c6a92a16530fd7101c53fd39eeae05c
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 "cryptfs.h" 42#define LOG_TAG "Cryptfs" 43#include "cutils/android_reboot.h" 44#include "cutils/log.h" 45#include "cutils/properties.h" 46#include "hardware_legacy/power.h" 47#include "VolumeManager.h" 48 49#define DM_CRYPT_BUF_SIZE 4096 50#define DATA_MNT_POINT "/data" 51 52#define HASH_COUNT 2000 53#define KEY_LEN_BYTES 16 54#define IV_LEN_BYTES 16 55 56#define KEY_LOC_PROP "ro.crypto.keyfile.userdata" 57#define KEY_IN_FOOTER "footer" 58 59#define EXT4_FS 1 60#define FAT_FS 2 61 62char *me = "cryptfs"; 63 64static unsigned char saved_master_key[KEY_LEN_BYTES]; 65static char *saved_data_blkdev; 66static char *saved_mount_point; 67static int master_key_saved = 0; 68 69static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) 70{ 71 memset(io, 0, dataSize); 72 io->data_size = dataSize; 73 io->data_start = sizeof(struct dm_ioctl); 74 io->version[0] = 4; 75 io->version[1] = 0; 76 io->version[2] = 0; 77 io->flags = flags; 78 if (name) { 79 strncpy(io->name, name, sizeof(io->name)); 80 } 81} 82 83static unsigned int get_fs_size(char *dev) 84{ 85 int fd, block_size; 86 struct ext4_super_block sb; 87 off64_t len; 88 89 if ((fd = open(dev, O_RDONLY)) < 0) { 90 SLOGE("Cannot open device to get filesystem size "); 91 return 0; 92 } 93 94 if (lseek64(fd, 1024, SEEK_SET) < 0) { 95 SLOGE("Cannot seek to superblock"); 96 return 0; 97 } 98 99 if (read(fd, &sb, sizeof(sb)) != sizeof(sb)) { 100 SLOGE("Cannot read superblock"); 101 return 0; 102 } 103 104 close(fd); 105 106 block_size = 1024 << sb.s_log_block_size; 107 /* compute length in bytes */ 108 len = ( ((off64_t)sb.s_blocks_count_hi << 32) + sb.s_blocks_count_lo) * block_size; 109 110 /* return length in sectors */ 111 return (unsigned int) (len / 512); 112} 113 114static unsigned int get_blkdev_size(int fd) 115{ 116 unsigned int nr_sec; 117 118 if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { 119 nr_sec = 0; 120 } 121 122 return nr_sec; 123} 124 125/* key or salt can be NULL, in which case just skip writing that value. Useful to 126 * update the failed mount count but not change the key. 127 */ 128static int put_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 129 unsigned char *key, unsigned char *salt) 130{ 131 int fd; 132 unsigned int nr_sec, cnt; 133 off64_t off; 134 int rc = -1; 135 char *fname; 136 char key_loc[PROPERTY_VALUE_MAX]; 137 struct stat statbuf; 138 139 property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); 140 141 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 142 fname = real_blk_name; 143 if ( (fd = open(fname, O_RDWR)) < 0) { 144 SLOGE("Cannot open real block device %s\n", fname); 145 return -1; 146 } 147 148 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 149 SLOGE("Cannot get size of block device %s\n", fname); 150 goto errout; 151 } 152 153 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 154 * encryption info footer and key, and plenty of bytes to spare for future 155 * growth. 156 */ 157 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 158 159 if (lseek64(fd, off, SEEK_SET) == -1) { 160 SLOGE("Cannot seek to real block device footer\n"); 161 goto errout; 162 } 163 } else if (key_loc[0] == '/') { 164 fname = key_loc; 165 if ( (fd = open(fname, O_RDWR | O_CREAT, 0600)) < 0) { 166 SLOGE("Cannot open footer file %s\n", fname); 167 return -1; 168 } 169 } else { 170 SLOGE("Unexpected value for" KEY_LOC_PROP "\n"); 171 return -1;; 172 } 173 174 if ((cnt = write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 175 SLOGE("Cannot write real block device footer\n"); 176 goto errout; 177 } 178 179 if (key) { 180 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 181 SLOGE("Keysize of %d bits not supported for real block device %s\n", 182 crypt_ftr->keysize*8, fname); 183 goto errout; 184 } 185 186 if ( (cnt = write(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 187 SLOGE("Cannot write key for real block device %s\n", fname); 188 goto errout; 189 } 190 } 191 192 if (salt) { 193 /* Compute the offset from the last write to the salt */ 194 off = KEY_TO_SALT_PADDING; 195 if (! key) 196 off += crypt_ftr->keysize; 197 198 if (lseek64(fd, off, SEEK_CUR) == -1) { 199 SLOGE("Cannot seek to real block device salt \n"); 200 goto errout; 201 } 202 203 if ( (cnt = write(fd, salt, SALT_LEN)) != SALT_LEN) { 204 SLOGE("Cannot write salt for real block device %s\n", fname); 205 goto errout; 206 } 207 } 208 209 fstat(fd, &statbuf); 210 /* If the keys are kept on a raw block device, do not try to truncate it. */ 211 if (S_ISREG(statbuf.st_mode) && (key_loc[0] == '/')) { 212 if (ftruncate(fd, 0x4000)) { 213 SLOGE("Cannot set footer file size\n", fname); 214 goto errout; 215 } 216 } 217 218 /* Success! */ 219 rc = 0; 220 221errout: 222 close(fd); 223 return rc; 224 225} 226 227static int get_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 228 unsigned char *key, unsigned char *salt) 229{ 230 int fd; 231 unsigned int nr_sec, cnt; 232 off64_t off; 233 int rc = -1; 234 char key_loc[PROPERTY_VALUE_MAX]; 235 char *fname; 236 struct stat statbuf; 237 238 property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); 239 240 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 241 fname = real_blk_name; 242 if ( (fd = open(fname, O_RDONLY)) < 0) { 243 SLOGE("Cannot open real block device %s\n", fname); 244 return -1; 245 } 246 247 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 248 SLOGE("Cannot get size of block device %s\n", fname); 249 goto errout; 250 } 251 252 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 253 * encryption info footer and key, and plenty of bytes to spare for future 254 * growth. 255 */ 256 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 257 258 if (lseek64(fd, off, SEEK_SET) == -1) { 259 SLOGE("Cannot seek to real block device footer\n"); 260 goto errout; 261 } 262 } else if (key_loc[0] == '/') { 263 fname = key_loc; 264 if ( (fd = open(fname, O_RDONLY)) < 0) { 265 SLOGE("Cannot open footer file %s\n", fname); 266 return -1; 267 } 268 269 /* Make sure it's 16 Kbytes in length */ 270 fstat(fd, &statbuf); 271 if (S_ISREG(statbuf.st_mode) && (statbuf.st_size != 0x4000)) { 272 SLOGE("footer file %s is not the expected size!\n", fname); 273 goto errout; 274 } 275 } else { 276 SLOGE("Unexpected value for" KEY_LOC_PROP "\n"); 277 return -1;; 278 } 279 280 if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 281 SLOGE("Cannot read real block device footer\n"); 282 goto errout; 283 } 284 285 if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { 286 SLOGE("Bad magic for real block device %s\n", fname); 287 goto errout; 288 } 289 290 if (crypt_ftr->major_version != 1) { 291 SLOGE("Cannot understand major version %d real block device footer\n", 292 crypt_ftr->major_version); 293 goto errout; 294 } 295 296 if (crypt_ftr->minor_version != 0) { 297 SLOGW("Warning: crypto footer minor version %d, expected 0, continuing...\n", 298 crypt_ftr->minor_version); 299 } 300 301 if (crypt_ftr->ftr_size > sizeof(struct crypt_mnt_ftr)) { 302 /* the footer size is bigger than we expected. 303 * Skip to it's stated end so we can read the key. 304 */ 305 if (lseek(fd, crypt_ftr->ftr_size - sizeof(struct crypt_mnt_ftr), SEEK_CUR) == -1) { 306 SLOGE("Cannot seek to start of key\n"); 307 goto errout; 308 } 309 } 310 311 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 312 SLOGE("Keysize of %d bits not supported for real block device %s\n", 313 crypt_ftr->keysize * 8, fname); 314 goto errout; 315 } 316 317 if ( (cnt = read(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 318 SLOGE("Cannot read key for real block device %s\n", fname); 319 goto errout; 320 } 321 322 if (lseek64(fd, KEY_TO_SALT_PADDING, SEEK_CUR) == -1) { 323 SLOGE("Cannot seek to real block device salt\n"); 324 goto errout; 325 } 326 327 if ( (cnt = read(fd, salt, SALT_LEN)) != SALT_LEN) { 328 SLOGE("Cannot read salt for real block device %s\n", fname); 329 goto errout; 330 } 331 332 /* Success! */ 333 rc = 0; 334 335errout: 336 close(fd); 337 return rc; 338} 339 340/* Convert a binary key of specified length into an ascii hex string equivalent, 341 * without the leading 0x and with null termination 342 */ 343void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, 344 char *master_key_ascii) 345{ 346 unsigned int i, a; 347 unsigned char nibble; 348 349 for (i=0, a=0; i<keysize; i++, a+=2) { 350 /* For each byte, write out two ascii hex digits */ 351 nibble = (master_key[i] >> 4) & 0xf; 352 master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); 353 354 nibble = master_key[i] & 0xf; 355 master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); 356 } 357 358 /* Add the null termination */ 359 master_key_ascii[a] = '\0'; 360 361} 362 363static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, 364 char *real_blk_name, char *crypto_blk_name, const char *name) 365{ 366 char buffer[DM_CRYPT_BUF_SIZE]; 367 char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ 368 char *crypt_params; 369 struct dm_ioctl *io; 370 struct dm_target_spec *tgt; 371 unsigned int minor; 372 int fd; 373 int retval = -1; 374 375 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 376 SLOGE("Cannot open device-mapper\n"); 377 goto errout; 378 } 379 380 io = (struct dm_ioctl *) buffer; 381 382 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 383 if (ioctl(fd, DM_DEV_CREATE, io)) { 384 SLOGE("Cannot create dm-crypt device\n"); 385 goto errout; 386 } 387 388 /* Get the device status, in particular, the name of it's device file */ 389 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 390 if (ioctl(fd, DM_DEV_STATUS, io)) { 391 SLOGE("Cannot retrieve dm-crypt device status\n"); 392 goto errout; 393 } 394 minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); 395 snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); 396 397 /* Load the mapping table for this device */ 398 tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; 399 400 ioctl_init(io, 4096, name, 0); 401 io->target_count = 1; 402 tgt->status = 0; 403 tgt->sector_start = 0; 404 tgt->length = crypt_ftr->fs_size; 405 strcpy(tgt->target_type, "crypt"); 406 407 crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); 408 convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); 409 sprintf(crypt_params, "%s %s 0 %s 0", crypt_ftr->crypto_type_name, 410 master_key_ascii, real_blk_name); 411 crypt_params += strlen(crypt_params) + 1; 412 crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ 413 tgt->next = crypt_params - buffer; 414 415 if (ioctl(fd, DM_TABLE_LOAD, io)) { 416 SLOGE("Cannot load dm-crypt mapping table.\n"); 417 goto errout; 418 } 419 420 /* Resume this device to activate it */ 421 ioctl_init(io, 4096, name, 0); 422 423 if (ioctl(fd, DM_DEV_SUSPEND, io)) { 424 SLOGE("Cannot resume the dm-crypt device\n"); 425 goto errout; 426 } 427 428 /* We made it here with no errors. Woot! */ 429 retval = 0; 430 431errout: 432 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 433 434 return retval; 435} 436 437static int delete_crypto_blk_dev(char *name) 438{ 439 int fd; 440 char buffer[DM_CRYPT_BUF_SIZE]; 441 struct dm_ioctl *io; 442 int retval = -1; 443 444 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 445 SLOGE("Cannot open device-mapper\n"); 446 goto errout; 447 } 448 449 io = (struct dm_ioctl *) buffer; 450 451 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 452 if (ioctl(fd, DM_DEV_REMOVE, io)) { 453 SLOGE("Cannot remove dm-crypt device\n"); 454 goto errout; 455 } 456 457 /* We made it here with no errors. Woot! */ 458 retval = 0; 459 460errout: 461 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 462 463 return retval; 464 465} 466 467static void pbkdf2(char *passwd, unsigned char *salt, unsigned char *ikey) 468{ 469 /* Turn the password into a key and IV that can decrypt the master key */ 470 PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN, 471 HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); 472} 473 474static int encrypt_master_key(char *passwd, unsigned char *salt, 475 unsigned char *decrypted_master_key, 476 unsigned char *encrypted_master_key) 477{ 478 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 479 EVP_CIPHER_CTX e_ctx; 480 int encrypted_len, final_len; 481 482 /* Turn the password into a key and IV that can decrypt the master key */ 483 pbkdf2(passwd, salt, ikey); 484 485 /* Initialize the decryption engine */ 486 if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 487 SLOGE("EVP_EncryptInit failed\n"); 488 return -1; 489 } 490 EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ 491 492 /* Encrypt the master key */ 493 if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len, 494 decrypted_master_key, KEY_LEN_BYTES)) { 495 SLOGE("EVP_EncryptUpdate failed\n"); 496 return -1; 497 } 498 if (! EVP_EncryptFinal(&e_ctx, encrypted_master_key + encrypted_len, &final_len)) { 499 SLOGE("EVP_EncryptFinal failed\n"); 500 return -1; 501 } 502 503 if (encrypted_len + final_len != KEY_LEN_BYTES) { 504 SLOGE("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); 505 return -1; 506 } else { 507 return 0; 508 } 509} 510 511static int decrypt_master_key(char *passwd, unsigned char *salt, 512 unsigned char *encrypted_master_key, 513 unsigned char *decrypted_master_key) 514{ 515 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 516 EVP_CIPHER_CTX d_ctx; 517 int decrypted_len, final_len; 518 519 /* Turn the password into a key and IV that can decrypt the master key */ 520 pbkdf2(passwd, salt, ikey); 521 522 /* Initialize the decryption engine */ 523 if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 524 return -1; 525 } 526 EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ 527 /* Decrypt the master key */ 528 if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, 529 encrypted_master_key, KEY_LEN_BYTES)) { 530 return -1; 531 } 532 if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { 533 return -1; 534 } 535 536 if (decrypted_len + final_len != KEY_LEN_BYTES) { 537 return -1; 538 } else { 539 return 0; 540 } 541} 542 543static int create_encrypted_random_key(char *passwd, unsigned char *master_key, unsigned char *salt) 544{ 545 int fd; 546 unsigned char key_buf[KEY_LEN_BYTES]; 547 EVP_CIPHER_CTX e_ctx; 548 int encrypted_len, final_len; 549 550 /* Get some random bits for a key */ 551 fd = open("/dev/urandom", O_RDONLY); 552 read(fd, key_buf, sizeof(key_buf)); 553 read(fd, salt, SALT_LEN); 554 close(fd); 555 556 /* Now encrypt it with the password */ 557 return encrypt_master_key(passwd, salt, key_buf, master_key); 558} 559 560static int get_orig_mount_parms(char *mount_point, char *fs_type, char *real_blkdev, 561 unsigned long *mnt_flags, char *fs_options) 562{ 563 char mount_point2[PROPERTY_VALUE_MAX]; 564 char fs_flags[PROPERTY_VALUE_MAX]; 565 566 property_get("ro.crypto.fs_type", fs_type, ""); 567 property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); 568 property_get("ro.crypto.fs_mnt_point", mount_point2, ""); 569 property_get("ro.crypto.fs_options", fs_options, ""); 570 property_get("ro.crypto.fs_flags", fs_flags, ""); 571 *mnt_flags = strtol(fs_flags, 0, 0); 572 573 if (strcmp(mount_point, mount_point2)) { 574 /* Consistency check. These should match. If not, something odd happened. */ 575 return -1; 576 } 577 578 return 0; 579} 580 581static int wait_and_unmount(char *mountpoint) 582{ 583 int i, rc; 584#define WAIT_UNMOUNT_COUNT 20 585 586 /* Now umount the tmpfs filesystem */ 587 for (i=0; i<WAIT_UNMOUNT_COUNT; i++) { 588 if (umount(mountpoint)) { 589 if (errno == EINVAL) { 590 /* EINVAL is returned if the directory is not a mountpoint, 591 * i.e. there is no filesystem mounted there. So just get out. 592 */ 593 break; 594 } 595 sleep(1); 596 i++; 597 } else { 598 break; 599 } 600 } 601 602 if (i < WAIT_UNMOUNT_COUNT) { 603 SLOGD("unmounting %s succeeded\n", mountpoint); 604 rc = 0; 605 } else { 606 SLOGE("unmounting %s failed\n", mountpoint); 607 rc = -1; 608 } 609 610 return rc; 611} 612 613#define DATA_PREP_TIMEOUT 100 614static int prep_data_fs(void) 615{ 616 int i; 617 618 /* Do the prep of the /data filesystem */ 619 property_set("vold.post_fs_data_done", "0"); 620 property_set("vold.decrypt", "trigger_post_fs_data"); 621 SLOGD("Just triggered post_fs_data\n"); 622 623 /* Wait a max of 25 seconds, hopefully it takes much less */ 624 for (i=0; i<DATA_PREP_TIMEOUT; i++) { 625 char p[PROPERTY_VALUE_MAX]; 626 627 property_get("vold.post_fs_data_done", p, "0"); 628 if (*p == '1') { 629 break; 630 } else { 631 usleep(250000); 632 } 633 } 634 if (i == DATA_PREP_TIMEOUT) { 635 /* Ugh, we failed to prep /data in time. Bail. */ 636 return -1; 637 } else { 638 SLOGD("post_fs_data done\n"); 639 return 0; 640 } 641} 642 643int cryptfs_restart(void) 644{ 645 char fs_type[32]; 646 char real_blkdev[MAXPATHLEN]; 647 char crypto_blkdev[MAXPATHLEN]; 648 char fs_options[256]; 649 unsigned long mnt_flags; 650 struct stat statbuf; 651 int rc = -1, i; 652 static int restart_successful = 0; 653 654 /* Validate that it's OK to call this routine */ 655 if (! master_key_saved) { 656 SLOGE("Encrypted filesystem not validated, aborting"); 657 return -1; 658 } 659 660 if (restart_successful) { 661 SLOGE("System already restarted with encrypted disk, aborting"); 662 return -1; 663 } 664 665 /* Here is where we shut down the framework. The init scripts 666 * start all services in one of three classes: core, main or late_start. 667 * On boot, we start core and main. Now, we stop main, but not core, 668 * as core includes vold and a few other really important things that 669 * we need to keep running. Once main has stopped, we should be able 670 * to umount the tmpfs /data, then mount the encrypted /data. 671 * We then restart the class main, and also the class late_start. 672 * At the moment, I've only put a few things in late_start that I know 673 * are not needed to bring up the framework, and that also cause problems 674 * with unmounting the tmpfs /data, but I hope to add add more services 675 * to the late_start class as we optimize this to decrease the delay 676 * till the user is asked for the password to the filesystem. 677 */ 678 679 /* The init files are setup to stop the class main when vold.decrypt is 680 * set to trigger_reset_main. 681 */ 682 property_set("vold.decrypt", "trigger_reset_main"); 683 SLOGD("Just asked init to shut down class main\n"); 684 685 /* Now that the framework is shutdown, we should be able to umount() 686 * the tmpfs filesystem, and mount the real one. 687 */ 688 689 property_get("ro.crypto.fs_crypto_blkdev", crypto_blkdev, ""); 690 if (strlen(crypto_blkdev) == 0) { 691 SLOGE("fs_crypto_blkdev not set\n"); 692 return -1; 693 } 694 695 if (! get_orig_mount_parms(DATA_MNT_POINT, fs_type, real_blkdev, &mnt_flags, fs_options)) { 696 SLOGD("Just got orig mount parms\n"); 697 698 if (! (rc = wait_and_unmount(DATA_MNT_POINT)) ) { 699 /* If that succeeded, then mount the decrypted filesystem */ 700 mount(crypto_blkdev, DATA_MNT_POINT, fs_type, mnt_flags, fs_options); 701 702 property_set("vold.decrypt", "trigger_load_persist_props"); 703 /* Create necessary paths on /data */ 704 if (prep_data_fs()) { 705 return -1; 706 } 707 708 /* startup service classes main and late_start */ 709 property_set("vold.decrypt", "trigger_restart_framework"); 710 SLOGD("Just triggered restart_framework\n"); 711 712 /* Give it a few moments to get started */ 713 sleep(1); 714 } 715 } 716 717 if (rc == 0) { 718 restart_successful = 1; 719 } 720 721 return rc; 722} 723 724static int do_crypto_complete(char *mount_point) 725{ 726 struct crypt_mnt_ftr crypt_ftr; 727 unsigned char encrypted_master_key[32]; 728 unsigned char salt[SALT_LEN]; 729 char real_blkdev[MAXPATHLEN]; 730 char fs_type[PROPERTY_VALUE_MAX]; 731 char fs_options[PROPERTY_VALUE_MAX]; 732 unsigned long mnt_flags; 733 char encrypted_state[PROPERTY_VALUE_MAX]; 734 char key_loc[PROPERTY_VALUE_MAX]; 735 736 property_get("ro.crypto.state", encrypted_state, ""); 737 if (strcmp(encrypted_state, "encrypted") ) { 738 SLOGE("not running with encryption, aborting"); 739 return 1; 740 } 741 742 if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 743 SLOGE("Error reading original mount parms for mount point %s\n", mount_point); 744 return -1; 745 } 746 747 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 748 property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); 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 fs_type[PROPERTY_VALUE_MAX]; 784 char fs_options[PROPERTY_VALUE_MAX]; 785 char tmp_mount_point[64]; 786 unsigned long mnt_flags; 787 unsigned int orig_failed_decrypt_count; 788 char encrypted_state[PROPERTY_VALUE_MAX]; 789 int rc; 790 791 property_get("ro.crypto.state", encrypted_state, ""); 792 if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) { 793 SLOGE("encrypted fs already validated or not running with encryption, aborting"); 794 return -1; 795 } 796 797 if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 798 SLOGE("Error reading original mount parms for mount point %s\n", mount_point); 799 return -1; 800 } 801 802 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 803 SLOGE("Error getting crypt footer and key\n"); 804 return -1; 805 } 806 807 SLOGD("crypt_ftr->fs_size = %lld\n", crypt_ftr.fs_size); 808 orig_failed_decrypt_count = crypt_ftr.failed_decrypt_count; 809 810 if (! (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { 811 decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); 812 } 813 814 if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, 815 real_blkdev, crypto_blkdev, label)) { 816 SLOGE("Error creating decrypted block device\n"); 817 return -1; 818 } 819 820 /* If init detects an encrypted filesystme, it writes a file for each such 821 * encrypted fs into the tmpfs /data filesystem, and then the framework finds those 822 * files and passes that data to me */ 823 /* Create a tmp mount point to try mounting the decryptd fs 824 * Since we're here, the mount_point should be a tmpfs filesystem, so make 825 * a directory in it to test mount the decrypted filesystem. 826 */ 827 sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); 828 mkdir(tmp_mount_point, 0755); 829 if ( mount(crypto_blkdev, tmp_mount_point, "ext4", MS_RDONLY, "") ) { 830 SLOGE("Error temp mounting decrypted block device\n"); 831 delete_crypto_blk_dev(label); 832 crypt_ftr.failed_decrypt_count++; 833 } else { 834 /* Success, so just umount and we'll mount it properly when we restart 835 * the framework. 836 */ 837 umount(tmp_mount_point); 838 crypt_ftr.failed_decrypt_count = 0; 839 } 840 841 if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) { 842 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 843 } 844 845 if (crypt_ftr.failed_decrypt_count) { 846 /* We failed to mount the device, so return an error */ 847 rc = crypt_ftr.failed_decrypt_count; 848 849 } else { 850 /* Woot! Success! Save the name of the crypto block device 851 * so we can mount it when restarting the framework. 852 */ 853 property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); 854 855 /* Also save a the master key so we can reencrypted the key 856 * the key when we want to change the password on it. 857 */ 858 memcpy(saved_master_key, decrypted_master_key, KEY_LEN_BYTES); 859 saved_data_blkdev = strdup(real_blkdev); 860 saved_mount_point = strdup(mount_point); 861 master_key_saved = 1; 862 rc = 0; 863 } 864 865 return rc; 866} 867 868/* Called by vold when it wants to undo the crypto mapping of a volume it 869 * manages. This is usually in response to a factory reset, when we want 870 * to undo the crypto mapping so the volume is formatted in the clear. 871 */ 872int cryptfs_revert_volume(const char *label) 873{ 874 return delete_crypto_blk_dev((char *)label); 875} 876 877/* 878 * Called by vold when it's asked to mount an encrypted, nonremovable volume. 879 * Setup a dm-crypt mapping, use the saved master key from 880 * setting up the /data mapping, and return the new device path. 881 */ 882int cryptfs_setup_volume(const char *label, int major, int minor, 883 char *crypto_sys_path, unsigned int max_path, 884 int *new_major, int *new_minor) 885{ 886 char real_blkdev[MAXPATHLEN], crypto_blkdev[MAXPATHLEN]; 887 struct crypt_mnt_ftr sd_crypt_ftr; 888 unsigned char key[32], salt[32]; 889 struct stat statbuf; 890 int nr_sec, fd; 891 892 sprintf(real_blkdev, "/dev/block/vold/%d:%d", major, minor); 893 894 /* Just want the footer, but gotta get it all */ 895 get_crypt_ftr_and_key(saved_data_blkdev, &sd_crypt_ftr, key, salt); 896 897 /* Update the fs_size field to be the size of the volume */ 898 fd = open(real_blkdev, O_RDONLY); 899 nr_sec = get_blkdev_size(fd); 900 close(fd); 901 if (nr_sec == 0) { 902 SLOGE("Cannot get size of volume %s\n", real_blkdev); 903 return -1; 904 } 905 906 sd_crypt_ftr.fs_size = nr_sec; 907 create_crypto_blk_dev(&sd_crypt_ftr, saved_master_key, real_blkdev, 908 crypto_blkdev, label); 909 910 stat(crypto_blkdev, &statbuf); 911 *new_major = MAJOR(statbuf.st_rdev); 912 *new_minor = MINOR(statbuf.st_rdev); 913 914 /* Create path to sys entry for this block device */ 915 snprintf(crypto_sys_path, max_path, "/devices/virtual/block/%s", strrchr(crypto_blkdev, '/')+1); 916 917 return 0; 918} 919 920int cryptfs_crypto_complete(void) 921{ 922 return do_crypto_complete("/data"); 923} 924 925int cryptfs_check_passwd(char *passwd) 926{ 927 int rc = -1; 928 929 rc = test_mount_encrypted_fs(passwd, DATA_MNT_POINT, "userdata"); 930 931 return rc; 932} 933 934int cryptfs_verify_passwd(char *passwd) 935{ 936 struct crypt_mnt_ftr crypt_ftr; 937 /* Allocate enough space for a 256 bit key, but we may use less */ 938 unsigned char encrypted_master_key[32], decrypted_master_key[32]; 939 unsigned char salt[SALT_LEN]; 940 char real_blkdev[MAXPATHLEN]; 941 char fs_type[PROPERTY_VALUE_MAX]; 942 char fs_options[PROPERTY_VALUE_MAX]; 943 unsigned long mnt_flags; 944 char encrypted_state[PROPERTY_VALUE_MAX]; 945 int rc; 946 947 property_get("ro.crypto.state", encrypted_state, ""); 948 if (strcmp(encrypted_state, "encrypted") ) { 949 SLOGE("device not encrypted, aborting"); 950 return -2; 951 } 952 953 if (!master_key_saved) { 954 SLOGE("encrypted fs not yet mounted, aborting"); 955 return -1; 956 } 957 958 if (!saved_mount_point) { 959 SLOGE("encrypted fs failed to save mount point, aborting"); 960 return -1; 961 } 962 963 if (get_orig_mount_parms(saved_mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 964 SLOGE("Error reading original mount parms for mount point %s\n", saved_mount_point); 965 return -1; 966 } 967 968 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 969 SLOGE("Error getting crypt footer and key\n"); 970 return -1; 971 } 972 973 if (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) { 974 /* If the device has no password, then just say the password is valid */ 975 rc = 0; 976 } else { 977 decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); 978 if (!memcmp(decrypted_master_key, saved_master_key, crypt_ftr.keysize)) { 979 /* They match, the password is correct */ 980 rc = 0; 981 } else { 982 /* If incorrect, sleep for a bit to prevent dictionary attacks */ 983 sleep(1); 984 rc = 1; 985 } 986 } 987 988 return rc; 989} 990 991/* Initialize a crypt_mnt_ftr structure. The keysize is 992 * defaulted to 16 bytes, and the filesystem size to 0. 993 * Presumably, at a minimum, the caller will update the 994 * filesystem size and crypto_type_name after calling this function. 995 */ 996static void cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) 997{ 998 ftr->magic = CRYPT_MNT_MAGIC; 999 ftr->major_version = 1; 1000 ftr->minor_version = 0; 1001 ftr->ftr_size = sizeof(struct crypt_mnt_ftr); 1002 ftr->flags = 0; 1003 ftr->keysize = KEY_LEN_BYTES; 1004 ftr->spare1 = 0; 1005 ftr->fs_size = 0; 1006 ftr->failed_decrypt_count = 0; 1007 ftr->crypto_type_name[0] = '\0'; 1008} 1009 1010static int cryptfs_enable_wipe(char *crypto_blkdev, off64_t size, int type) 1011{ 1012 char cmdline[256]; 1013 int rc = -1; 1014 1015 if (type == EXT4_FS) { 1016 snprintf(cmdline, sizeof(cmdline), "/system/bin/make_ext4fs -a /data -l %lld %s", 1017 size * 512, crypto_blkdev); 1018 SLOGI("Making empty filesystem with command %s\n", cmdline); 1019 } else if (type== FAT_FS) { 1020 snprintf(cmdline, sizeof(cmdline), "/system/bin/newfs_msdos -F 32 -O android -c 8 -s %lld %s", 1021 size, crypto_blkdev); 1022 SLOGI("Making empty filesystem with command %s\n", cmdline); 1023 } else { 1024 SLOGE("cryptfs_enable_wipe(): unknown filesystem type %d\n", type); 1025 return -1; 1026 } 1027 1028 if (system(cmdline)) { 1029 SLOGE("Error creating empty filesystem on %s\n", crypto_blkdev); 1030 } else { 1031 SLOGD("Successfully created empty filesystem on %s\n", crypto_blkdev); 1032 rc = 0; 1033 } 1034 1035 return rc; 1036} 1037 1038static inline int unix_read(int fd, void* buff, int len) 1039{ 1040 int ret; 1041 do { ret = read(fd, buff, len); } while (ret < 0 && errno == EINTR); 1042 return ret; 1043} 1044 1045static inline int unix_write(int fd, const void* buff, int len) 1046{ 1047 int ret; 1048 do { ret = write(fd, buff, len); } while (ret < 0 && errno == EINTR); 1049 return ret; 1050} 1051 1052#define CRYPT_INPLACE_BUFSIZE 4096 1053#define CRYPT_SECTORS_PER_BUFSIZE (CRYPT_INPLACE_BUFSIZE / 512) 1054static int cryptfs_enable_inplace(char *crypto_blkdev, char *real_blkdev, off64_t size, 1055 off64_t *size_already_done, off64_t tot_size) 1056{ 1057 int realfd, cryptofd; 1058 char *buf[CRYPT_INPLACE_BUFSIZE]; 1059 int rc = -1; 1060 off64_t numblocks, i, remainder; 1061 off64_t one_pct, cur_pct, new_pct; 1062 off64_t blocks_already_done, tot_numblocks; 1063 1064 if ( (realfd = open(real_blkdev, O_RDONLY)) < 0) { 1065 SLOGE("Error opening real_blkdev %s for inplace encrypt\n", real_blkdev); 1066 return -1; 1067 } 1068 1069 if ( (cryptofd = open(crypto_blkdev, O_WRONLY)) < 0) { 1070 SLOGE("Error opening crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1071 close(realfd); 1072 return -1; 1073 } 1074 1075 /* This is pretty much a simple loop of reading 4K, and writing 4K. 1076 * The size passed in is the number of 512 byte sectors in the filesystem. 1077 * So compute the number of whole 4K blocks we should read/write, 1078 * and the remainder. 1079 */ 1080 numblocks = size / CRYPT_SECTORS_PER_BUFSIZE; 1081 remainder = size % CRYPT_SECTORS_PER_BUFSIZE; 1082 tot_numblocks = tot_size / CRYPT_SECTORS_PER_BUFSIZE; 1083 blocks_already_done = *size_already_done / CRYPT_SECTORS_PER_BUFSIZE; 1084 1085 SLOGE("Encrypting filesystem in place..."); 1086 1087 one_pct = tot_numblocks / 100; 1088 cur_pct = 0; 1089 /* process the majority of the filesystem in blocks */ 1090 for (i=0; i<numblocks; i++) { 1091 new_pct = (i + blocks_already_done) / one_pct; 1092 if (new_pct > cur_pct) { 1093 char buf[8]; 1094 1095 cur_pct = new_pct; 1096 snprintf(buf, sizeof(buf), "%lld", cur_pct); 1097 property_set("vold.encrypt_progress", buf); 1098 } 1099 if (unix_read(realfd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 1100 SLOGE("Error reading real_blkdev %s for inplace encrypt\n", crypto_blkdev); 1101 goto errout; 1102 } 1103 if (unix_write(cryptofd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 1104 SLOGE("Error writing crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1105 goto errout; 1106 } 1107 } 1108 1109 /* Do any remaining sectors */ 1110 for (i=0; i<remainder; i++) { 1111 if (unix_read(realfd, buf, 512) <= 0) { 1112 SLOGE("Error reading rival sectors from real_blkdev %s for inplace encrypt\n", crypto_blkdev); 1113 goto errout; 1114 } 1115 if (unix_write(cryptofd, buf, 512) <= 0) { 1116 SLOGE("Error writing final sectors to crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 1117 goto errout; 1118 } 1119 } 1120 1121 *size_already_done += size; 1122 rc = 0; 1123 1124errout: 1125 close(realfd); 1126 close(cryptofd); 1127 1128 return rc; 1129} 1130 1131#define CRYPTO_ENABLE_WIPE 1 1132#define CRYPTO_ENABLE_INPLACE 2 1133 1134#define FRAMEWORK_BOOT_WAIT 60 1135 1136static inline int should_encrypt(struct volume_info *volume) 1137{ 1138 return (volume->flags & (VOL_ENCRYPTABLE | VOL_NONREMOVABLE)) == 1139 (VOL_ENCRYPTABLE | VOL_NONREMOVABLE); 1140} 1141 1142int cryptfs_enable(char *howarg, char *passwd) 1143{ 1144 int how = 0; 1145 char crypto_blkdev[MAXPATHLEN], real_blkdev[MAXPATHLEN], sd_crypto_blkdev[MAXPATHLEN]; 1146 char fs_type[PROPERTY_VALUE_MAX], fs_options[PROPERTY_VALUE_MAX], 1147 mount_point[PROPERTY_VALUE_MAX]; 1148 unsigned long mnt_flags, nr_sec; 1149 unsigned char master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 1150 unsigned char salt[SALT_LEN]; 1151 int rc=-1, fd, i, ret; 1152 struct crypt_mnt_ftr crypt_ftr, sd_crypt_ftr;; 1153 char tmpfs_options[PROPERTY_VALUE_MAX]; 1154 char encrypted_state[PROPERTY_VALUE_MAX]; 1155 char lockid[32] = { 0 }; 1156 char key_loc[PROPERTY_VALUE_MAX]; 1157 char fuse_sdcard[PROPERTY_VALUE_MAX]; 1158 char *sd_mnt_point; 1159 char sd_blk_dev[256] = { 0 }; 1160 int num_vols; 1161 struct volume_info *vol_list = 0; 1162 off64_t cur_encryption_done=0, tot_encryption_size=0; 1163 1164 property_get("ro.crypto.state", encrypted_state, ""); 1165 if (strcmp(encrypted_state, "unencrypted")) { 1166 SLOGE("Device is already running encrypted, aborting"); 1167 goto error_unencrypted; 1168 } 1169 1170 property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); 1171 1172 if (!strcmp(howarg, "wipe")) { 1173 how = CRYPTO_ENABLE_WIPE; 1174 } else if (! strcmp(howarg, "inplace")) { 1175 how = CRYPTO_ENABLE_INPLACE; 1176 } else { 1177 /* Shouldn't happen, as CommandListener vets the args */ 1178 goto error_unencrypted; 1179 } 1180 1181 get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options); 1182 1183 /* Get the size of the real block device */ 1184 fd = open(real_blkdev, O_RDONLY); 1185 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 1186 SLOGE("Cannot get size of block device %s\n", real_blkdev); 1187 goto error_unencrypted; 1188 } 1189 close(fd); 1190 1191 /* If doing inplace encryption, make sure the orig fs doesn't include the crypto footer */ 1192 if ((how == CRYPTO_ENABLE_INPLACE) && (!strcmp(key_loc, KEY_IN_FOOTER))) { 1193 unsigned int fs_size_sec, max_fs_size_sec; 1194 1195 fs_size_sec = get_fs_size(real_blkdev); 1196 max_fs_size_sec = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 1197 1198 if (fs_size_sec > max_fs_size_sec) { 1199 SLOGE("Orig filesystem overlaps crypto footer region. Cannot encrypt in place."); 1200 goto error_unencrypted; 1201 } 1202 } 1203 1204 /* Get a wakelock as this may take a while, and we don't want the 1205 * device to sleep on us. We'll grab a partial wakelock, and if the UI 1206 * wants to keep the screen on, it can grab a full wakelock. 1207 */ 1208 snprintf(lockid, sizeof(lockid), "enablecrypto%d", (int) getpid()); 1209 acquire_wake_lock(PARTIAL_WAKE_LOCK, lockid); 1210 1211 /* Get the sdcard mount point */ 1212 sd_mnt_point = getenv("EXTERNAL_STORAGE"); 1213 if (! sd_mnt_point) { 1214 sd_mnt_point = "/mnt/sdcard"; 1215 } 1216 1217 num_vols=vold_getNumDirectVolumes(); 1218 vol_list = malloc(sizeof(struct volume_info) * num_vols); 1219 vold_getDirectVolumeList(vol_list); 1220 1221 for (i=0; i<num_vols; i++) { 1222 if (should_encrypt(&vol_list[i])) { 1223 fd = open(vol_list[i].blk_dev, O_RDONLY); 1224 if ( (vol_list[i].size = get_blkdev_size(fd)) == 0) { 1225 SLOGE("Cannot get size of block device %s\n", vol_list[i].blk_dev); 1226 goto error_unencrypted; 1227 } 1228 close(fd); 1229 1230 ret=vold_disableVol(vol_list[i].label); 1231 if ((ret < 0) && (ret != UNMOUNT_NOT_MOUNTED_ERR)) { 1232 /* -2 is returned when the device exists but is not currently mounted. 1233 * ignore the error and continue. */ 1234 SLOGE("Failed to unmount volume %s\n", vol_list[i].label); 1235 goto error_unencrypted; 1236 } 1237 } 1238 } 1239 1240 /* The init files are setup to stop the class main and late start when 1241 * vold sets trigger_shutdown_framework. 1242 */ 1243 property_set("vold.decrypt", "trigger_shutdown_framework"); 1244 SLOGD("Just asked init to shut down class main\n"); 1245 1246 property_get("ro.crypto.fuse_sdcard", fuse_sdcard, ""); 1247 if (!strcmp(fuse_sdcard, "true")) { 1248 /* This is a device using the fuse layer to emulate the sdcard semantics 1249 * on top of the userdata partition. vold does not manage it, it is managed 1250 * by the sdcard service. The sdcard service was killed by the property trigger 1251 * above, so just unmount it now. We must do this _AFTER_ killing the framework, 1252 * unlike the case for vold managed devices above. 1253 */ 1254 if (wait_and_unmount(sd_mnt_point)) { 1255 goto error_shutting_down; 1256 } 1257 } 1258 1259 /* Now unmount the /data partition. */ 1260 if (wait_and_unmount(DATA_MNT_POINT)) { 1261 goto error_shutting_down; 1262 } 1263 1264 /* Do extra work for a better UX when doing the long inplace encryption */ 1265 if (how == CRYPTO_ENABLE_INPLACE) { 1266 /* Now that /data is unmounted, we need to mount a tmpfs 1267 * /data, set a property saying we're doing inplace encryption, 1268 * and restart the framework. 1269 */ 1270 property_get("ro.crypto.tmpfs_options", tmpfs_options, ""); 1271 if (mount("tmpfs", DATA_MNT_POINT, "tmpfs", MS_NOATIME | MS_NOSUID | MS_NODEV, 1272 tmpfs_options) < 0) { 1273 goto error_shutting_down; 1274 } 1275 /* Tells the framework that inplace encryption is starting */ 1276 property_set("vold.encrypt_progress", "0"); 1277 1278 /* restart the framework. */ 1279 /* Create necessary paths on /data */ 1280 if (prep_data_fs()) { 1281 goto error_shutting_down; 1282 } 1283 1284 /* startup service classes main and late_start */ 1285 property_set("vold.decrypt", "trigger_restart_min_framework"); 1286 SLOGD("Just triggered restart_min_framework\n"); 1287 1288 /* OK, the framework is restarted and will soon be showing a 1289 * progress bar. Time to setup an encrypted mapping, and 1290 * either write a new filesystem, or encrypt in place updating 1291 * the progress bar as we work. 1292 */ 1293 } 1294 1295 /* Start the actual work of making an encrypted filesystem */ 1296 /* Initialize a crypt_mnt_ftr for the partition */ 1297 cryptfs_init_crypt_mnt_ftr(&crypt_ftr); 1298 if (!strcmp(key_loc, KEY_IN_FOOTER)) { 1299 crypt_ftr.fs_size = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 1300 } else { 1301 crypt_ftr.fs_size = nr_sec; 1302 } 1303 crypt_ftr.flags |= CRYPT_ENCRYPTION_IN_PROGRESS; 1304 strcpy((char *)crypt_ftr.crypto_type_name, "aes-cbc-essiv:sha256"); 1305 1306 /* Make an encrypted master key */ 1307 if (create_encrypted_random_key(passwd, master_key, salt)) { 1308 SLOGE("Cannot create encrypted master key\n"); 1309 goto error_unencrypted; 1310 } 1311 1312 /* Write the key to the end of the partition */ 1313 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, master_key, salt); 1314 1315 decrypt_master_key(passwd, salt, master_key, decrypted_master_key); 1316 create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, real_blkdev, crypto_blkdev, 1317 "userdata"); 1318 1319 /* The size of the userdata partition, and add in the vold volumes below */ 1320 tot_encryption_size = crypt_ftr.fs_size; 1321 1322 /* setup crypto mapping for all encryptable volumes handled by vold */ 1323 for (i=0; i<num_vols; i++) { 1324 if (should_encrypt(&vol_list[i])) { 1325 vol_list[i].crypt_ftr = crypt_ftr; /* gotta love struct assign */ 1326 vol_list[i].crypt_ftr.fs_size = vol_list[i].size; 1327 create_crypto_blk_dev(&vol_list[i].crypt_ftr, decrypted_master_key, 1328 vol_list[i].blk_dev, vol_list[i].crypto_blkdev, 1329 vol_list[i].label); 1330 tot_encryption_size += vol_list[i].size; 1331 } 1332 } 1333 1334 if (how == CRYPTO_ENABLE_WIPE) { 1335 rc = cryptfs_enable_wipe(crypto_blkdev, crypt_ftr.fs_size, EXT4_FS); 1336 /* Encrypt all encryptable volumes handled by vold */ 1337 if (!rc) { 1338 for (i=0; i<num_vols; i++) { 1339 if (should_encrypt(&vol_list[i])) { 1340 rc = cryptfs_enable_wipe(vol_list[i].crypto_blkdev, 1341 vol_list[i].crypt_ftr.fs_size, FAT_FS); 1342 } 1343 } 1344 } 1345 } else if (how == CRYPTO_ENABLE_INPLACE) { 1346 rc = cryptfs_enable_inplace(crypto_blkdev, real_blkdev, crypt_ftr.fs_size, 1347 &cur_encryption_done, tot_encryption_size); 1348 /* Encrypt all encryptable volumes handled by vold */ 1349 if (!rc) { 1350 for (i=0; i<num_vols; i++) { 1351 if (should_encrypt(&vol_list[i])) { 1352 rc = cryptfs_enable_inplace(vol_list[i].crypto_blkdev, 1353 vol_list[i].blk_dev, 1354 vol_list[i].crypt_ftr.fs_size, 1355 &cur_encryption_done, tot_encryption_size); 1356 } 1357 } 1358 } 1359 if (!rc) { 1360 /* The inplace routine never actually sets the progress to 100% 1361 * due to the round down nature of integer division, so set it here */ 1362 property_set("vold.encrypt_progress", "100"); 1363 } 1364 } else { 1365 /* Shouldn't happen */ 1366 SLOGE("cryptfs_enable: internal error, unknown option\n"); 1367 goto error_unencrypted; 1368 } 1369 1370 /* Undo the dm-crypt mapping whether we succeed or not */ 1371 delete_crypto_blk_dev("userdata"); 1372 for (i=0; i<num_vols; i++) { 1373 if (should_encrypt(&vol_list[i])) { 1374 delete_crypto_blk_dev(vol_list[i].label); 1375 } 1376 } 1377 1378 free(vol_list); 1379 1380 if (! rc) { 1381 /* Success */ 1382 1383 /* Clear the encryption in progres flag in the footer */ 1384 crypt_ftr.flags &= ~CRYPT_ENCRYPTION_IN_PROGRESS; 1385 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 1386 1387 sleep(2); /* Give the UI a chance to show 100% progress */ 1388 android_reboot(ANDROID_RB_RESTART, 0, 0); 1389 } else { 1390 char value[PROPERTY_VALUE_MAX]; 1391 1392 property_get("ro.vold.wipe_on_cyrypt_fail", value, "0"); 1393 if (!strcmp(value, "1")) { 1394 /* wipe data if encryption failed */ 1395 SLOGE("encryption failed - rebooting into recovery to wipe data\n"); 1396 mkdir("/cache/recovery", 0700); 1397 int fd = open("/cache/recovery/command", O_RDWR|O_CREAT|O_TRUNC); 1398 if (fd >= 0) { 1399 write(fd, "--wipe_data", strlen("--wipe_data") + 1); 1400 close(fd); 1401 } else { 1402 SLOGE("could not open /cache/recovery/command\n"); 1403 } 1404 android_reboot(ANDROID_RB_RESTART2, 0, "recovery"); 1405 } else { 1406 /* set property to trigger dialog */ 1407 property_set("vold.encrypt_progress", "error_partially_encrypted"); 1408 release_wake_lock(lockid); 1409 } 1410 return -1; 1411 } 1412 1413 /* hrm, the encrypt step claims success, but the reboot failed. 1414 * This should not happen. 1415 * Set the property and return. Hope the framework can deal with it. 1416 */ 1417 property_set("vold.encrypt_progress", "error_reboot_failed"); 1418 release_wake_lock(lockid); 1419 return rc; 1420 1421error_unencrypted: 1422 free(vol_list); 1423 property_set("vold.encrypt_progress", "error_not_encrypted"); 1424 if (lockid[0]) { 1425 release_wake_lock(lockid); 1426 } 1427 return -1; 1428 1429error_shutting_down: 1430 /* we failed, and have not encrypted anthing, so the users's data is still intact, 1431 * but the framework is stopped and not restarted to show the error, so it's up to 1432 * vold to restart the system. 1433 */ 1434 SLOGE("Error enabling encryption after framework is shutdown, no data changed, restarting system"); 1435 android_reboot(ANDROID_RB_RESTART, 0, 0); 1436 1437 /* shouldn't get here */ 1438 property_set("vold.encrypt_progress", "error_shutting_down"); 1439 free(vol_list); 1440 if (lockid[0]) { 1441 release_wake_lock(lockid); 1442 } 1443 return -1; 1444} 1445 1446int cryptfs_changepw(char *newpw) 1447{ 1448 struct crypt_mnt_ftr crypt_ftr; 1449 unsigned char encrypted_master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 1450 unsigned char salt[SALT_LEN]; 1451 char real_blkdev[MAXPATHLEN]; 1452 1453 /* This is only allowed after we've successfully decrypted the master key */ 1454 if (! master_key_saved) { 1455 SLOGE("Key not saved, aborting"); 1456 return -1; 1457 } 1458 1459 property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); 1460 if (strlen(real_blkdev) == 0) { 1461 SLOGE("Can't find real blkdev"); 1462 return -1; 1463 } 1464 1465 /* get key */ 1466 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 1467 SLOGE("Error getting crypt footer and key"); 1468 return -1; 1469 } 1470 1471 encrypt_master_key(newpw, salt, saved_master_key, encrypted_master_key); 1472 1473 /* save the key */ 1474 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt); 1475 1476 return 0; 1477} 1478