cryptfs.c revision 7f7dbaa2784c10fd2989fb303e5edfb8136d53dc
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 <sys/reboot.h> 39#include <ext4.h> 40#include "cryptfs.h" 41#define LOG_TAG "Cryptfs" 42#include "cutils/log.h" 43#include "cutils/properties.h" 44#include "hardware_legacy/power.h" 45 46#define DM_CRYPT_BUF_SIZE 4096 47#define DATA_MNT_POINT "/data" 48 49#define HASH_COUNT 2000 50#define KEY_LEN_BYTES 16 51#define IV_LEN_BYTES 16 52 53char *me = "cryptfs"; 54 55static unsigned char saved_master_key[KEY_LEN_BYTES]; 56static int master_key_saved = 0; 57 58static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) 59{ 60 memset(io, 0, dataSize); 61 io->data_size = dataSize; 62 io->data_start = sizeof(struct dm_ioctl); 63 io->version[0] = 4; 64 io->version[1] = 0; 65 io->version[2] = 0; 66 io->flags = flags; 67 if (name) { 68 strncpy(io->name, name, sizeof(io->name)); 69 } 70} 71 72static unsigned int get_fs_size(char *dev) 73{ 74 int fd, block_size; 75 struct ext4_super_block sb; 76 off64_t len; 77 78 if ((fd = open(dev, O_RDONLY)) < 0) { 79 SLOGE("Cannot open device to get filesystem size "); 80 return 0; 81 } 82 83 if (lseek64(fd, 1024, SEEK_SET) < 0) { 84 SLOGE("Cannot seek to superblock"); 85 return 0; 86 } 87 88 if (read(fd, &sb, sizeof(sb)) != sizeof(sb)) { 89 SLOGE("Cannot read superblock"); 90 return 0; 91 } 92 93 close(fd); 94 95 block_size = 1024 << sb.s_log_block_size; 96 /* compute length in bytes */ 97 len = ( ((off64_t)sb.s_blocks_count_hi << 32) + sb.s_blocks_count_lo) * block_size; 98 99 /* return length in sectors */ 100 return (unsigned int) (len / 512); 101} 102 103static unsigned int get_blkdev_size(int fd) 104{ 105 unsigned int nr_sec; 106 107 if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { 108 nr_sec = 0; 109 } 110 111 return nr_sec; 112} 113 114/* key or salt can be NULL, in which case just skip writing that value. Useful to 115 * update the failed mount count but not change the key. 116 */ 117static int put_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 118 unsigned char *key, unsigned char *salt) 119{ 120 int fd; 121 unsigned int nr_sec, cnt; 122 off64_t off; 123 int rc = -1; 124 125 if ( (fd = open(real_blk_name, O_RDWR)) < 0) { 126 SLOGE("Cannot open real block device %s\n", real_blk_name); 127 return -1; 128 } 129 130 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 131 SLOGE("Cannot get size of block device %s\n", real_blk_name); 132 goto errout; 133 } 134 135 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 136 * encryption info footer and key, and plenty of bytes to spare for future 137 * growth. 138 */ 139 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 140 141 if (lseek64(fd, off, SEEK_SET) == -1) { 142 SLOGE("Cannot seek to real block device footer\n"); 143 goto errout; 144 } 145 146 if ((cnt = write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 147 SLOGE("Cannot write real block device footer\n"); 148 goto errout; 149 } 150 151 if (key) { 152 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 153 SLOGE("Keysize of %d bits not supported for real block device %s\n", 154 crypt_ftr->keysize * 8, real_blk_name); 155 goto errout; 156 } 157 158 if ( (cnt = write(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 159 SLOGE("Cannot write key for real block device %s\n", real_blk_name); 160 goto errout; 161 } 162 } 163 164 if (salt) { 165 /* Compute the offset for start of the crypt footer */ 166 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 167 /* Add in the length of the footer, key and padding */ 168 off += sizeof(struct crypt_mnt_ftr) + crypt_ftr->keysize + KEY_TO_SALT_PADDING; 169 170 if (lseek64(fd, off, SEEK_SET) == -1) { 171 SLOGE("Cannot seek to real block device salt \n"); 172 goto errout; 173 } 174 175 if ( (cnt = write(fd, salt, SALT_LEN)) != SALT_LEN) { 176 SLOGE("Cannot write salt for real block device %s\n", real_blk_name); 177 goto errout; 178 } 179 } 180 181 /* Success! */ 182 rc = 0; 183 184errout: 185 close(fd); 186 return rc; 187 188} 189 190static int get_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 191 unsigned char *key, unsigned char *salt) 192{ 193 int fd; 194 unsigned int nr_sec, cnt; 195 off64_t off; 196 int rc = -1; 197 198 if ( (fd = open(real_blk_name, O_RDWR)) < 0) { 199 SLOGE("Cannot open real block device %s\n", real_blk_name); 200 return -1; 201 } 202 203 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 204 SLOGE("Cannot get size of block device %s\n", real_blk_name); 205 goto errout; 206 } 207 208 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 209 * encryption info footer and key, and plenty of bytes to spare for future 210 * growth. 211 */ 212 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 213 214 if (lseek64(fd, off, SEEK_SET) == -1) { 215 SLOGE("Cannot seek to real block device footer\n"); 216 goto errout; 217 } 218 219 if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 220 SLOGE("Cannot read real block device footer\n"); 221 goto errout; 222 } 223 224 if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { 225 SLOGE("Bad magic for real block device %s\n", real_blk_name); 226 goto errout; 227 } 228 229 if (crypt_ftr->major_version != 1) { 230 SLOGE("Cannot understand major version %d real block device footer\n", 231 crypt_ftr->major_version); 232 goto errout; 233 } 234 235 if (crypt_ftr->minor_version != 0) { 236 SLOGW("Warning: crypto footer minor version %d, expected 0, continuing...\n", 237 crypt_ftr->minor_version); 238 } 239 240 if (crypt_ftr->ftr_size > sizeof(struct crypt_mnt_ftr)) { 241 /* the footer size is bigger than we expected. 242 * Skip to it's stated end so we can read the key. 243 */ 244 if (lseek(fd, crypt_ftr->ftr_size - sizeof(struct crypt_mnt_ftr), SEEK_CUR) == -1) { 245 SLOGE("Cannot seek to start of key\n"); 246 goto errout; 247 } 248 } 249 250 if (crypt_ftr->keysize != KEY_LEN_BYTES) { 251 SLOGE("Keysize of %d bits not supported for real block device %s\n", 252 crypt_ftr->keysize * 8, real_blk_name); 253 goto errout; 254 } 255 256 if ( (cnt = read(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 257 SLOGE("Cannot read key for real block device %s\n", real_blk_name); 258 goto errout; 259 } 260 261 if (lseek64(fd, KEY_TO_SALT_PADDING, SEEK_CUR) == -1) { 262 SLOGE("Cannot seek to real block device salt\n"); 263 goto errout; 264 } 265 266 if ( (cnt = read(fd, salt, SALT_LEN)) != SALT_LEN) { 267 SLOGE("Cannot read salt for real block device %s\n", real_blk_name); 268 goto errout; 269 } 270 271 /* Success! */ 272 rc = 0; 273 274errout: 275 close(fd); 276 return rc; 277} 278 279/* Convert a binary key of specified length into an ascii hex string equivalent, 280 * without the leading 0x and with null termination 281 */ 282void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, 283 char *master_key_ascii) 284{ 285 unsigned int i, a; 286 unsigned char nibble; 287 288 for (i=0, a=0; i<keysize; i++, a+=2) { 289 /* For each byte, write out two ascii hex digits */ 290 nibble = (master_key[i] >> 4) & 0xf; 291 master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); 292 293 nibble = master_key[i] & 0xf; 294 master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); 295 } 296 297 /* Add the null termination */ 298 master_key_ascii[a] = '\0'; 299 300} 301 302static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, 303 char *real_blk_name, char *crypto_blk_name) 304{ 305 char buffer[DM_CRYPT_BUF_SIZE]; 306 char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ 307 char *crypt_params; 308 struct dm_ioctl *io; 309 struct dm_target_spec *tgt; 310 unsigned int minor; 311 int fd; 312 int retval = -1; 313 char *name ="datadev"; /* FIX ME: Make me a parameter */ 314 315 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 316 SLOGE("Cannot open device-mapper\n"); 317 goto errout; 318 } 319 320 io = (struct dm_ioctl *) buffer; 321 322 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 323 if (ioctl(fd, DM_DEV_CREATE, io)) { 324 SLOGE("Cannot create dm-crypt device\n"); 325 goto errout; 326 } 327 328 /* Get the device status, in particular, the name of it's device file */ 329 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 330 if (ioctl(fd, DM_DEV_STATUS, io)) { 331 SLOGE("Cannot retrieve dm-crypt device status\n"); 332 goto errout; 333 } 334 minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); 335 snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); 336 337 /* Load the mapping table for this device */ 338 tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; 339 340 ioctl_init(io, 4096, name, 0); 341 io->target_count = 1; 342 tgt->status = 0; 343 tgt->sector_start = 0; 344 tgt->length = crypt_ftr->fs_size; 345 strcpy(tgt->target_type, "crypt"); 346 347 crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); 348 convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); 349 sprintf(crypt_params, "%s %s 0 %s 0", crypt_ftr->crypto_type_name, 350 master_key_ascii, real_blk_name); 351 crypt_params += strlen(crypt_params) + 1; 352 crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ 353 tgt->next = crypt_params - buffer; 354 355 if (ioctl(fd, DM_TABLE_LOAD, io)) { 356 SLOGE("Cannot load dm-crypt mapping table.\n"); 357 goto errout; 358 } 359 360 /* Resume this device to activate it */ 361 ioctl_init(io, 4096, name, 0); 362 363 if (ioctl(fd, DM_DEV_SUSPEND, io)) { 364 SLOGE("Cannot resume the dm-crypt device\n"); 365 goto errout; 366 } 367 368 /* We made it here with no errors. Woot! */ 369 retval = 0; 370 371errout: 372 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 373 374 return retval; 375} 376 377static int delete_crypto_blk_dev(char *crypto_blkdev) 378{ 379 int fd; 380 char buffer[DM_CRYPT_BUF_SIZE]; 381 struct dm_ioctl *io; 382 char *name ="datadev"; /* FIX ME: Make me a paraameter */ 383 int retval = -1; 384 385 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 386 SLOGE("Cannot open device-mapper\n"); 387 goto errout; 388 } 389 390 io = (struct dm_ioctl *) buffer; 391 392 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 393 if (ioctl(fd, DM_DEV_REMOVE, io)) { 394 SLOGE("Cannot remove dm-crypt device\n"); 395 goto errout; 396 } 397 398 /* We made it here with no errors. Woot! */ 399 retval = 0; 400 401errout: 402 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 403 404 return retval; 405 406} 407 408static void pbkdf2(char *passwd, unsigned char *salt, unsigned char *ikey) 409{ 410 /* Turn the password into a key and IV that can decrypt the master key */ 411 PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN, 412 HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); 413} 414 415static int encrypt_master_key(char *passwd, unsigned char *salt, 416 unsigned char *decrypted_master_key, 417 unsigned char *encrypted_master_key) 418{ 419 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 420 EVP_CIPHER_CTX e_ctx; 421 int encrypted_len, final_len; 422 423 /* Turn the password into a key and IV that can decrypt the master key */ 424 pbkdf2(passwd, salt, ikey); 425 426 /* Initialize the decryption engine */ 427 if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 428 SLOGE("EVP_EncryptInit failed\n"); 429 return -1; 430 } 431 EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ 432 433 /* Encrypt the master key */ 434 if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len, 435 decrypted_master_key, KEY_LEN_BYTES)) { 436 SLOGE("EVP_EncryptUpdate failed\n"); 437 return -1; 438 } 439 if (! EVP_EncryptFinal(&e_ctx, encrypted_master_key + encrypted_len, &final_len)) { 440 SLOGE("EVP_EncryptFinal failed\n"); 441 return -1; 442 } 443 444 if (encrypted_len + final_len != KEY_LEN_BYTES) { 445 SLOGE("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); 446 return -1; 447 } else { 448 return 0; 449 } 450} 451 452static int decrypt_master_key(char *passwd, unsigned char *salt, 453 unsigned char *encrypted_master_key, 454 unsigned char *decrypted_master_key) 455{ 456 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 457 EVP_CIPHER_CTX d_ctx; 458 int decrypted_len, final_len; 459 460 /* Turn the password into a key and IV that can decrypt the master key */ 461 pbkdf2(passwd, salt, ikey); 462 463 /* Initialize the decryption engine */ 464 if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 465 return -1; 466 } 467 EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ 468 /* Decrypt the master key */ 469 if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, 470 encrypted_master_key, KEY_LEN_BYTES)) { 471 return -1; 472 } 473 if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { 474 return -1; 475 } 476 477 if (decrypted_len + final_len != KEY_LEN_BYTES) { 478 return -1; 479 } else { 480 return 0; 481 } 482} 483 484static int create_encrypted_random_key(char *passwd, unsigned char *master_key, unsigned char *salt) 485{ 486 int fd; 487 unsigned char key_buf[KEY_LEN_BYTES]; 488 EVP_CIPHER_CTX e_ctx; 489 int encrypted_len, final_len; 490 491 /* Get some random bits for a key */ 492 fd = open("/dev/urandom", O_RDONLY); 493 read(fd, key_buf, sizeof(key_buf)); 494 read(fd, salt, SALT_LEN); 495 close(fd); 496 497 /* Now encrypt it with the password */ 498 return encrypt_master_key(passwd, salt, key_buf, master_key); 499} 500 501static int get_orig_mount_parms(char *mount_point, char *fs_type, char *real_blkdev, 502 unsigned long *mnt_flags, char *fs_options) 503{ 504 char mount_point2[32]; 505 char fs_flags[32]; 506 507 property_get("ro.crypto.fs_type", fs_type, ""); 508 property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); 509 property_get("ro.crypto.fs_mnt_point", mount_point2, ""); 510 property_get("ro.crypto.fs_options", fs_options, ""); 511 property_get("ro.crypto.fs_flags", fs_flags, ""); 512 *mnt_flags = strtol(fs_flags, 0, 0); 513 514 if (strcmp(mount_point, mount_point2)) { 515 /* Consistency check. These should match. If not, something odd happened. */ 516 return -1; 517 } 518 519 return 0; 520} 521 522static int wait_and_unmount(char *mountpoint) 523{ 524 int i, rc; 525#define WAIT_UNMOUNT_COUNT 20 526 527 /* Now umount the tmpfs filesystem */ 528 for (i=0; i<WAIT_UNMOUNT_COUNT; i++) { 529 if (umount(mountpoint)) { 530 sleep(1); 531 i++; 532 } else { 533 break; 534 } 535 } 536 537 if (i < WAIT_UNMOUNT_COUNT) { 538 SLOGD("unmounting %s succeeded\n", mountpoint); 539 rc = 0; 540 } else { 541 SLOGE("unmounting %s failed\n", mountpoint); 542 rc = -1; 543 } 544 545 return rc; 546} 547 548#define DATA_PREP_TIMEOUT 100 549static int prep_data_fs(void) 550{ 551 int i; 552 553 /* Do the prep of the /data filesystem */ 554 property_set("vold.post_fs_data_done", "0"); 555 property_set("vold.decrypt", "trigger_post_fs_data"); 556 SLOGD("Just triggered post_fs_data\n"); 557 558 /* Wait a max of 25 seconds, hopefully it takes much less */ 559 for (i=0; i<DATA_PREP_TIMEOUT; i++) { 560 char p[16];; 561 562 property_get("vold.post_fs_data_done", p, "0"); 563 if (*p == '1') { 564 break; 565 } else { 566 usleep(250000); 567 } 568 } 569 if (i == DATA_PREP_TIMEOUT) { 570 /* Ugh, we failed to prep /data in time. Bail. */ 571 return -1; 572 } else { 573 SLOGD("post_fs_data done\n"); 574 return 0; 575 } 576} 577 578int cryptfs_restart(void) 579{ 580 char fs_type[32]; 581 char real_blkdev[MAXPATHLEN]; 582 char crypto_blkdev[MAXPATHLEN]; 583 char fs_options[256]; 584 unsigned long mnt_flags; 585 struct stat statbuf; 586 int rc = -1, i; 587 static int restart_successful = 0; 588 589 /* Validate that it's OK to call this routine */ 590 if (! master_key_saved) { 591 SLOGE("Encrypted filesystem not validated, aborting"); 592 return -1; 593 } 594 595 if (restart_successful) { 596 SLOGE("System already restarted with encrypted disk, aborting"); 597 return -1; 598 } 599 600 /* Here is where we shut down the framework. The init scripts 601 * start all services in one of three classes: core, main or late_start. 602 * On boot, we start core and main. Now, we stop main, but not core, 603 * as core includes vold and a few other really important things that 604 * we need to keep running. Once main has stopped, we should be able 605 * to umount the tmpfs /data, then mount the encrypted /data. 606 * We then restart the class main, and also the class late_start. 607 * At the moment, I've only put a few things in late_start that I know 608 * are not needed to bring up the framework, and that also cause problems 609 * with unmounting the tmpfs /data, but I hope to add add more services 610 * to the late_start class as we optimize this to decrease the delay 611 * till the user is asked for the password to the filesystem. 612 */ 613 614 /* The init files are setup to stop the class main when vold.decrypt is 615 * set to trigger_reset_main. 616 */ 617 property_set("vold.decrypt", "trigger_reset_main"); 618 SLOGD("Just asked init to shut down class main\n"); 619 620 /* Now that the framework is shutdown, we should be able to umount() 621 * the tmpfs filesystem, and mount the real one. 622 */ 623 624 property_get("ro.crypto.fs_crypto_blkdev", crypto_blkdev, ""); 625 if (strlen(crypto_blkdev) == 0) { 626 SLOGE("fs_crypto_blkdev not set\n"); 627 return -1; 628 } 629 630 if (! get_orig_mount_parms(DATA_MNT_POINT, fs_type, real_blkdev, &mnt_flags, fs_options)) { 631 SLOGD("Just got orig mount parms\n"); 632 633 if (! (rc = wait_and_unmount(DATA_MNT_POINT)) ) { 634 /* If that succeeded, then mount the decrypted filesystem */ 635 mount(crypto_blkdev, DATA_MNT_POINT, fs_type, mnt_flags, fs_options); 636 637 /* Create necessary paths on /data */ 638 if (prep_data_fs()) { 639 return -1; 640 } 641 642 /* startup service classes main and late_start */ 643 property_set("vold.decrypt", "trigger_restart_framework"); 644 SLOGD("Just triggered restart_framework\n"); 645 646 /* Give it a few moments to get started */ 647 sleep(1); 648 } 649 } 650 651 if (rc == 0) { 652 restart_successful = 1; 653 } 654 655 return rc; 656} 657 658static int do_crypto_complete(char *mount_point) 659{ 660 struct crypt_mnt_ftr crypt_ftr; 661 unsigned char encrypted_master_key[32]; 662 unsigned char salt[SALT_LEN]; 663 char real_blkdev[MAXPATHLEN]; 664 char fs_type[32]; 665 char fs_options[256]; 666 unsigned long mnt_flags; 667 char encrypted_state[32]; 668 669 property_get("ro.crypto.state", encrypted_state, ""); 670 if (strcmp(encrypted_state, "encrypted") ) { 671 SLOGE("not running with encryption, aborting"); 672 return 1; 673 } 674 675 if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 676 SLOGE("Error reading original mount parms for mount point %s\n", mount_point); 677 return -1; 678 } 679 680 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 681 SLOGE("Error getting crypt footer and key\n"); 682 return -1; 683 } 684 685 if (crypt_ftr.flags & CRYPT_ENCRYPTION_IN_PROGRESS) { 686 SLOGE("Encryption process didn't finish successfully\n"); 687 return -2; /* -2 is the clue to the UI that there is no usable data on the disk, 688 * and give the user an option to wipe the disk */ 689 } 690 691 /* We passed the test! We shall diminish, and return to the west */ 692 return 0; 693} 694 695static int test_mount_encrypted_fs(char *passwd, char *mount_point) 696{ 697 struct crypt_mnt_ftr crypt_ftr; 698 /* Allocate enough space for a 256 bit key, but we may use less */ 699 unsigned char encrypted_master_key[32], decrypted_master_key[32]; 700 unsigned char salt[SALT_LEN]; 701 char crypto_blkdev[MAXPATHLEN]; 702 char real_blkdev[MAXPATHLEN]; 703 char fs_type[32]; 704 char fs_options[256]; 705 char tmp_mount_point[64]; 706 unsigned long mnt_flags; 707 unsigned int orig_failed_decrypt_count; 708 char encrypted_state[32]; 709 int rc; 710 711 property_get("ro.crypto.state", encrypted_state, ""); 712 if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) { 713 SLOGE("encrypted fs already validated or not running with encryption, aborting"); 714 return -1; 715 } 716 717 if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 718 SLOGE("Error reading original mount parms for mount point %s\n", mount_point); 719 return -1; 720 } 721 722 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 723 SLOGE("Error getting crypt footer and key\n"); 724 return -1; 725 } 726 727 SLOGD("crypt_ftr->fs_size = %lld\n", crypt_ftr.fs_size); 728 orig_failed_decrypt_count = crypt_ftr.failed_decrypt_count; 729 730 if (! (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { 731 decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); 732 } 733 734 if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, 735 real_blkdev, crypto_blkdev)) { 736 SLOGE("Error creating decrypted block device\n"); 737 return -1; 738 } 739 740 /* If init detects an encrypted filesystme, it writes a file for each such 741 * encrypted fs into the tmpfs /data filesystem, and then the framework finds those 742 * files and passes that data to me */ 743 /* Create a tmp mount point to try mounting the decryptd fs 744 * Since we're here, the mount_point should be a tmpfs filesystem, so make 745 * a directory in it to test mount the decrypted filesystem. 746 */ 747 sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); 748 mkdir(tmp_mount_point, 0755); 749 if ( mount(crypto_blkdev, tmp_mount_point, "ext4", MS_RDONLY, "") ) { 750 SLOGE("Error temp mounting decrypted block device\n"); 751 delete_crypto_blk_dev(crypto_blkdev); 752 crypt_ftr.failed_decrypt_count++; 753 } else { 754 /* Success, so just umount and we'll mount it properly when we restart 755 * the framework. 756 */ 757 umount(tmp_mount_point); 758 crypt_ftr.failed_decrypt_count = 0; 759 } 760 761 if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) { 762 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 763 } 764 765 if (crypt_ftr.failed_decrypt_count) { 766 /* We failed to mount the device, so return an error */ 767 rc = crypt_ftr.failed_decrypt_count; 768 769 } else { 770 /* Woot! Success! Save the name of the crypto block device 771 * so we can mount it when restarting the framework. 772 */ 773 property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); 774 775 /* Also save a the master key so we can reencrypted the key 776 * the key when we want to change the password on it. 777 */ 778 memcpy(saved_master_key, decrypted_master_key, KEY_LEN_BYTES); 779 master_key_saved = 1; 780 rc = 0; 781 } 782 783 return rc; 784} 785 786int cryptfs_crypto_complete(void) 787{ 788 return do_crypto_complete("/data"); 789} 790 791int cryptfs_check_passwd(char *passwd) 792{ 793 int rc = -1; 794 795 rc = test_mount_encrypted_fs(passwd, DATA_MNT_POINT); 796 797 return rc; 798} 799 800/* Initialize a crypt_mnt_ftr structure. The keysize is 801 * defaulted to 16 bytes, and the filesystem size to 0. 802 * Presumably, at a minimum, the caller will update the 803 * filesystem size and crypto_type_name after calling this function. 804 */ 805static void cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) 806{ 807 ftr->magic = CRYPT_MNT_MAGIC; 808 ftr->major_version = 1; 809 ftr->minor_version = 0; 810 ftr->ftr_size = sizeof(struct crypt_mnt_ftr); 811 ftr->flags = 0; 812 ftr->keysize = KEY_LEN_BYTES; 813 ftr->spare1 = 0; 814 ftr->fs_size = 0; 815 ftr->failed_decrypt_count = 0; 816 ftr->crypto_type_name[0] = '\0'; 817} 818 819static int cryptfs_enable_wipe(char *crypto_blkdev, off64_t size) 820{ 821 char cmdline[256]; 822 int rc = -1; 823 824 snprintf(cmdline, sizeof(cmdline), "/system/bin/make_ext4fs -a /data -l %lld %s", 825 size * 512, crypto_blkdev); 826 SLOGI("Making empty filesystem with command %s\n", cmdline); 827 if (system(cmdline)) { 828 SLOGE("Error creating empty filesystem on %s\n", crypto_blkdev); 829 } else { 830 SLOGD("Successfully created empty filesystem on %s\n", crypto_blkdev); 831 rc = 0; 832 } 833 834 return rc; 835} 836 837static inline int unix_read(int fd, void* buff, int len) 838{ 839 int ret; 840 do { ret = read(fd, buff, len); } while (ret < 0 && errno == EINTR); 841 return ret; 842} 843 844static inline int unix_write(int fd, const void* buff, int len) 845{ 846 int ret; 847 do { ret = write(fd, buff, len); } while (ret < 0 && errno == EINTR); 848 return ret; 849} 850 851#define CRYPT_INPLACE_BUFSIZE 4096 852#define CRYPT_SECTORS_PER_BUFSIZE (CRYPT_INPLACE_BUFSIZE / 512) 853static int cryptfs_enable_inplace(char *crypto_blkdev, char *real_blkdev, off64_t size) 854{ 855 int realfd, cryptofd; 856 char *buf[CRYPT_INPLACE_BUFSIZE]; 857 int rc = -1; 858 off64_t numblocks, i, remainder; 859 off64_t one_pct, cur_pct, new_pct; 860 861 if ( (realfd = open(real_blkdev, O_RDONLY)) < 0) { 862 SLOGE("Error opening real_blkdev %s for inplace encrypt\n", real_blkdev); 863 return -1; 864 } 865 866 if ( (cryptofd = open(crypto_blkdev, O_WRONLY)) < 0) { 867 SLOGE("Error opening crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 868 close(realfd); 869 return -1; 870 } 871 872 /* This is pretty much a simple loop of reading 4K, and writing 4K. 873 * The size passed in is the number of 512 byte sectors in the filesystem. 874 * So compute the number of whole 4K blocks we should read/write, 875 * and the remainder. 876 */ 877 numblocks = size / CRYPT_SECTORS_PER_BUFSIZE; 878 remainder = size % CRYPT_SECTORS_PER_BUFSIZE; 879 880 SLOGE("Encrypting filesystem in place..."); 881 882 one_pct = numblocks / 100; 883 cur_pct = 0; 884 /* process the majority of the filesystem in blocks */ 885 for (i=0; i<numblocks; i++) { 886 new_pct = i / one_pct; 887 if (new_pct > cur_pct) { 888 char buf[8]; 889 890 cur_pct = new_pct; 891 snprintf(buf, sizeof(buf), "%lld", cur_pct); 892 property_set("vold.encrypt_progress", buf); 893 } 894 if (unix_read(realfd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 895 SLOGE("Error reading real_blkdev %s for inplace encrypt\n", crypto_blkdev); 896 goto errout; 897 } 898 if (unix_write(cryptofd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 899 SLOGE("Error writing crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 900 goto errout; 901 } 902 } 903 904 /* Do any remaining sectors */ 905 for (i=0; i<remainder; i++) { 906 if (unix_read(realfd, buf, 512) <= 0) { 907 SLOGE("Error reading rival sectors from real_blkdev %s for inplace encrypt\n", crypto_blkdev); 908 goto errout; 909 } 910 if (unix_write(cryptofd, buf, 512) <= 0) { 911 SLOGE("Error writing final sectors to crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 912 goto errout; 913 } 914 } 915 916 property_set("vold.encrypt_progress", "100"); 917 918 rc = 0; 919 920errout: 921 close(realfd); 922 close(cryptofd); 923 924 return rc; 925} 926 927#define CRYPTO_ENABLE_WIPE 1 928#define CRYPTO_ENABLE_INPLACE 2 929 930#define FRAMEWORK_BOOT_WAIT 60 931 932int cryptfs_enable(char *howarg, char *passwd) 933{ 934 int how = 0; 935 char crypto_blkdev[MAXPATHLEN], real_blkdev[MAXPATHLEN]; 936 char fs_type[32], fs_options[256], mount_point[32]; 937 unsigned long mnt_flags, nr_sec; 938 unsigned char master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 939 unsigned char salt[SALT_LEN]; 940 int rc=-1, fd, i; 941 struct crypt_mnt_ftr crypt_ftr; 942 char tmpfs_options[80]; 943 char encrypted_state[32]; 944 char lockid[32] = { 0 }; 945 946 property_get("ro.crypto.state", encrypted_state, ""); 947 if (strcmp(encrypted_state, "unencrypted")) { 948 SLOGE("Device is already running encrypted, aborting"); 949 goto error_unencrypted; 950 } 951 952 if (!strcmp(howarg, "wipe")) { 953 how = CRYPTO_ENABLE_WIPE; 954 } else if (! strcmp(howarg, "inplace")) { 955 how = CRYPTO_ENABLE_INPLACE; 956 } else { 957 /* Shouldn't happen, as CommandListener vets the args */ 958 goto error_unencrypted; 959 } 960 961 get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options); 962 963 /* Get the size of the real block device */ 964 fd = open(real_blkdev, O_RDONLY); 965 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 966 SLOGE("Cannot get size of block device %s\n", real_blkdev); 967 goto error_unencrypted; 968 } 969 close(fd); 970 971 /* If doing inplace encryption, make sure the orig fs doesn't include the crypto footer */ 972 if (how == CRYPTO_ENABLE_INPLACE) { 973 unsigned int fs_size_sec, max_fs_size_sec; 974 975 fs_size_sec = get_fs_size(real_blkdev); 976 max_fs_size_sec = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 977 978 if (fs_size_sec > max_fs_size_sec) { 979 SLOGE("Orig filesystem overlaps crypto footer region. Cannot encrypt in place."); 980 goto error_unencrypted; 981 } 982 } 983 984 /* Get a wakelock as this may take a while, and we don't want the 985 * device to sleep on us. We'll grab a partial wakelock, and if the UI 986 * wants to keep the screen on, it can grab a full wakelock. 987 */ 988 snprintf(lockid, 32, "enablecrypto%d", (int) getpid()); 989 acquire_wake_lock(PARTIAL_WAKE_LOCK, lockid); 990 991 /* The init files are setup to stop the class main and late start when 992 * vold sets trigger_shutdown_framework. 993 */ 994 property_set("vold.decrypt", "trigger_shutdown_framework"); 995 SLOGD("Just asked init to shut down class main\n"); 996 997 if (wait_and_unmount("/mnt/sdcard")) { 998 goto error_shutting_down; 999 } 1000 1001 /* Now unmount the /data partition. */ 1002 if (wait_and_unmount(DATA_MNT_POINT)) { 1003 goto error_shutting_down; 1004 } 1005 1006 /* Do extra work for a better UX when doing the long inplace encryption */ 1007 if (how == CRYPTO_ENABLE_INPLACE) { 1008 /* Now that /data is unmounted, we need to mount a tmpfs 1009 * /data, set a property saying we're doing inplace encryption, 1010 * and restart the framework. 1011 */ 1012 property_get("ro.crypto.tmpfs_options", tmpfs_options, ""); 1013 if (mount("tmpfs", DATA_MNT_POINT, "tmpfs", MS_NOATIME | MS_NOSUID | MS_NODEV, 1014 tmpfs_options) < 0) { 1015 goto error_shutting_down; 1016 } 1017 /* Tells the framework that inplace encryption is starting */ 1018 property_set("vold.encrypt_progress", "0"); 1019 1020 /* restart the framework. */ 1021 /* Create necessary paths on /data */ 1022 if (prep_data_fs()) { 1023 goto error_shutting_down; 1024 } 1025 1026 /* startup service classes main and late_start */ 1027 property_set("vold.decrypt", "trigger_restart_min_framework"); 1028 SLOGD("Just triggered restart_min_framework\n"); 1029 1030 /* OK, the framework is restarted and will soon be showing a 1031 * progress bar. Time to setup an encrypted mapping, and 1032 * either write a new filesystem, or encrypt in place updating 1033 * the progress bar as we work. 1034 */ 1035 } 1036 1037 /* Start the actual work of making an encrypted filesystem */ 1038 /* Initialize a crypt_mnt_ftr for the partition */ 1039 cryptfs_init_crypt_mnt_ftr(&crypt_ftr); 1040 crypt_ftr.fs_size = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 1041#if 0 /* Disable till MR1, needs more testing */ 1042 crypt_ftr.flags |= CRYPT_ENCRYPTION_IN_PROGRESS; 1043#endif 1044 strcpy((char *)crypt_ftr.crypto_type_name, "aes-cbc-essiv:sha256"); 1045 1046 /* Make an encrypted master key */ 1047 if (create_encrypted_random_key(passwd, master_key, salt)) { 1048 SLOGE("Cannot create encrypted master key\n"); 1049 goto error_unencrypted; 1050 } 1051 1052 /* Write the key to the end of the partition */ 1053 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, master_key, salt); 1054 1055 decrypt_master_key(passwd, salt, master_key, decrypted_master_key); 1056 create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, real_blkdev, crypto_blkdev); 1057 1058 if (how == CRYPTO_ENABLE_WIPE) { 1059 rc = cryptfs_enable_wipe(crypto_blkdev, crypt_ftr.fs_size); 1060 } else if (how == CRYPTO_ENABLE_INPLACE) { 1061 rc = cryptfs_enable_inplace(crypto_blkdev, real_blkdev, crypt_ftr.fs_size); 1062 } else { 1063 /* Shouldn't happen */ 1064 SLOGE("cryptfs_enable: internal error, unknown option\n"); 1065 goto error_unencrypted; 1066 } 1067 1068 /* Undo the dm-crypt mapping whether we succeed or not */ 1069 delete_crypto_blk_dev(crypto_blkdev); 1070 1071 if (! rc) { 1072 /* Success */ 1073 1074#if 0 /* Disable till MR1, needs more testing */ 1075 /* Clear the encryption in progres flag in the footer */ 1076 crypt_ftr.flags &= ~CRYPT_ENCRYPTION_IN_PROGRESS; 1077 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); 1078#endif 1079 1080 sleep(2); /* Give the UI a change to show 100% progress */ 1081 sync(); 1082 reboot(LINUX_REBOOT_CMD_RESTART); 1083 } else { 1084 property_set("vold.encrypt_progress", "error_partially_encrypted"); 1085 release_wake_lock(lockid); 1086 return -1; 1087 } 1088 1089 /* hrm, the encrypt step claims success, but the reboot failed. 1090 * This should not happen. 1091 * Set the property and return. Hope the framework can deal with it. 1092 */ 1093 property_set("vold.encrypt_progress", "error_reboot_failed"); 1094 release_wake_lock(lockid); 1095 return rc; 1096 1097error_unencrypted: 1098 property_set("vold.encrypt_progress", "error_not_encrypted"); 1099 if (lockid[0]) { 1100 release_wake_lock(lockid); 1101 } 1102 return -1; 1103 1104error_shutting_down: 1105 /* we failed, and have not encrypted anthing, so the users's data is still intact, 1106 * but the framework is stopped and not restarted to show the error, so it's up to 1107 * vold to restart the system. 1108 */ 1109 SLOGE("Error enabling encryption after framework is shutdown, no data changed, restarting system"); 1110 sync(); 1111 reboot(LINUX_REBOOT_CMD_RESTART); 1112 1113 /* shouldn't get here */ 1114 property_set("vold.encrypt_progress", "error_shutting_down"); 1115 if (lockid[0]) { 1116 release_wake_lock(lockid); 1117 } 1118 return -1; 1119} 1120 1121int cryptfs_changepw(char *newpw) 1122{ 1123 struct crypt_mnt_ftr crypt_ftr; 1124 unsigned char encrypted_master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; 1125 unsigned char salt[SALT_LEN]; 1126 char real_blkdev[MAXPATHLEN]; 1127 1128 /* This is only allowed after we've successfully decrypted the master key */ 1129 if (! master_key_saved) { 1130 SLOGE("Key not saved, aborting"); 1131 return -1; 1132 } 1133 1134 property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); 1135 if (strlen(real_blkdev) == 0) { 1136 SLOGE("Can't find real blkdev"); 1137 return -1; 1138 } 1139 1140 /* get key */ 1141 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { 1142 SLOGE("Error getting crypt footer and key"); 1143 return -1; 1144 } 1145 1146 encrypt_master_key(newpw, salt, saved_master_key, encrypted_master_key); 1147 1148 /* save the key */ 1149 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt); 1150 1151 return 0; 1152} 1153