cryptfs.c revision 6864b7ec94a57b73c300457955d86dc604aeddf5
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 <errno.h> 37#include <sys/reboot.h> 38#include "cryptfs.h" 39#define LOG_TAG "Cryptfs" 40#include "cutils/log.h" 41#include "cutils/properties.h" 42 43#define DM_CRYPT_BUF_SIZE 4096 44 45char *me = "cryptfs"; 46 47static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) 48{ 49 memset(io, 0, dataSize); 50 io->data_size = dataSize; 51 io->data_start = sizeof(struct dm_ioctl); 52 io->version[0] = 4; 53 io->version[1] = 0; 54 io->version[2] = 0; 55 io->flags = flags; 56 if (name) { 57 strncpy(io->name, name, sizeof(io->name)); 58 } 59} 60 61static unsigned int get_blkdev_size(int fd) 62{ 63 unsigned int nr_sec; 64 65 if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { 66 nr_sec = 0; 67 } 68 69 return nr_sec; 70} 71 72/* key can be NULL, in which case just write out the footer. Useful to 73 * update the failed mount count but not change the key. 74 */ 75static int put_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 76 unsigned char *key) 77{ 78 int fd; 79 unsigned int nr_sec, cnt; 80 off64_t off; 81 int rc = -1; 82 83 if ( (fd = open(real_blk_name, O_RDWR)) < 0) { 84 SLOGE("Cannot open real block device %s\n", real_blk_name); 85 return -1; 86 } 87 88 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 89 SLOGE("Cannot get size of block device %s\n", real_blk_name); 90 goto errout; 91 } 92 93 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 94 * encryption info footer and key, and plenty of bytes to spare for future 95 * growth. 96 */ 97 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 98 99 if (lseek64(fd, off, SEEK_SET) == -1) { 100 SLOGE("Cannot seek to real block device footer\n"); 101 goto errout; 102 } 103 104 if ((cnt = write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 105 SLOGE("Cannot write real block device footer\n"); 106 goto errout; 107 } 108 109 if (key) { 110 if (crypt_ftr->keysize != 16) { 111 SLOGE("Keysize of %d bits not supported for real block device %s\n", 112 crypt_ftr->keysize * 8, real_blk_name); 113 goto errout; 114 } 115 116 if ( (cnt = write(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 117 SLOGE("Cannot write key for real block device %s\n", real_blk_name); 118 goto errout; 119 } 120 } 121 122 /* Success! */ 123 rc = 0; 124 125errout: 126 close(fd); 127 return rc; 128 129} 130 131static int get_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, 132 unsigned char *key) 133{ 134 int fd; 135 unsigned int nr_sec, cnt; 136 off64_t off; 137 int rc = -1; 138 139 if ( (fd = open(real_blk_name, O_RDWR)) < 0) { 140 SLOGE("Cannot open real block device %s\n", real_blk_name); 141 return -1; 142 } 143 144 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 145 SLOGE("Cannot get size of block device %s\n", real_blk_name); 146 goto errout; 147 } 148 149 /* If it's an encrypted Android partition, the last 16 Kbytes contain the 150 * encryption info footer and key, and plenty of bytes to spare for future 151 * growth. 152 */ 153#if 1 /* The real location, use when the enable code works */ 154 off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; 155#else 156 /* For testing, I'm slapping a handbuild header after my 200 megabyte 157 * /data partition. So my offset if 200 megabytes */ 158 off = 200*1024*1024; 159#endif 160 161 if (lseek64(fd, off, SEEK_SET) == -1) { 162 SLOGE("Cannot seek to real block device footer\n"); 163 goto errout; 164 } 165 166 if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { 167 SLOGE("Cannot read real block device footer\n"); 168 goto errout; 169 } 170 171 if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { 172 SLOGE("Bad magic for real block device %s\n", real_blk_name); 173 goto errout; 174 } 175 176 if (crypt_ftr->major_version != 1) { 177 SLOGE("Cannot understand major version %d real block device footer\n", 178 crypt_ftr->major_version); 179 goto errout; 180 } 181 182 if (crypt_ftr->minor_version != 0) { 183 SLOGW("Warning: crypto footer minor version %d, expected 0, continuing...\n", 184 crypt_ftr->minor_version); 185 } 186 187 if (crypt_ftr->ftr_size > sizeof(struct crypt_mnt_ftr)) { 188 /* the footer size is bigger than we expected. 189 * Skip to it's stated end so we can read the key. 190 */ 191 if (lseek(fd, crypt_ftr->ftr_size - sizeof(struct crypt_mnt_ftr), SEEK_CUR) == -1) { 192 SLOGE("Cannot seek to start of key\n"); 193 goto errout; 194 } 195 } 196 197 if (crypt_ftr->keysize != 16) { 198 SLOGE("Keysize of %d bits not supported for real block device %s\n", 199 crypt_ftr->keysize * 8, real_blk_name); 200 goto errout; 201 } 202 203 if ( (cnt = read(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { 204 SLOGE("Cannot read key for real block device %s\n", real_blk_name); 205 goto errout; 206 } 207 208 /* Success! */ 209 rc = 0; 210 211errout: 212 close(fd); 213 return rc; 214} 215 216/* Convert a binary key of specified length into an ascii hex string equivalent, 217 * without the leading 0x and with null termination 218 */ 219void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, 220 char *master_key_ascii) 221{ 222 unsigned int i, a; 223 unsigned char nibble; 224 225 for (i=0, a=0; i<keysize; i++, a+=2) { 226 /* For each byte, write out two ascii hex digits */ 227 nibble = (master_key[i] >> 4) & 0xf; 228 master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); 229 230 nibble = master_key[i] & 0xf; 231 master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); 232 } 233 234 /* Add the null termination */ 235 master_key_ascii[a] = '\0'; 236 237} 238 239static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, 240 char *real_blk_name, char *crypto_blk_name) 241{ 242 char buffer[DM_CRYPT_BUF_SIZE]; 243 char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ 244 char *crypt_params; 245 struct dm_ioctl *io; 246 struct dm_target_spec *tgt; 247 unsigned int minor; 248 int fd; 249 int retval = -1; 250 char *name ="datadev"; /* FIX ME: Make me a parameter */ 251 252 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 253 SLOGE("Cannot open device-mapper\n"); 254 goto errout; 255 } 256 257 io = (struct dm_ioctl *) buffer; 258 259 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 260 if (ioctl(fd, DM_DEV_CREATE, io)) { 261 SLOGE("Cannot create dm-crypt device\n"); 262 goto errout; 263 } 264 265 /* Get the device status, in particular, the name of it's device file */ 266 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 267 if (ioctl(fd, DM_DEV_STATUS, io)) { 268 SLOGE("Cannot retrieve dm-crypt device status\n"); 269 goto errout; 270 } 271 minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); 272 snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); 273 274 /* Load the mapping table for this device */ 275 tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; 276 277 ioctl_init(io, 4096, name, 0); 278 io->target_count = 1; 279 tgt->status = 0; 280 tgt->sector_start = 0; 281 tgt->length = crypt_ftr->fs_size; 282 strcpy(tgt->target_type, "crypt"); 283 284 crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); 285 convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); 286 sprintf(crypt_params, "%s %s 0 %s 0", crypt_ftr->crypto_type_name, 287 master_key_ascii, real_blk_name); 288 //SLOGD("crypt_params = %s\n", crypt_params); // Only for debugging, prints the master key! 289 crypt_params += strlen(crypt_params) + 1; 290 crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ 291 tgt->next = crypt_params - buffer; 292 293 if (ioctl(fd, DM_TABLE_LOAD, io)) { 294 SLOGE("Cannot load dm-crypt mapping table.\n"); 295 goto errout; 296 } 297 298 /* Resume this device to activate it */ 299 ioctl_init(io, 4096, name, 0); 300 301 if (ioctl(fd, DM_DEV_SUSPEND, io)) { 302 SLOGE("Cannot resume the dm-crypt device\n"); 303 goto errout; 304 } 305 306 /* We made it here with no errors. Woot! */ 307 retval = 0; 308 309errout: 310 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 311 312 return retval; 313} 314 315static int delete_crypto_blk_dev(char *crypto_blkdev) 316{ 317 int fd; 318 char buffer[DM_CRYPT_BUF_SIZE]; 319 struct dm_ioctl *io; 320 char *name ="datadev"; /* FIX ME: Make me a paraameter */ 321 int retval = -1; 322 323 if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { 324 SLOGE("Cannot open device-mapper\n"); 325 goto errout; 326 } 327 328 io = (struct dm_ioctl *) buffer; 329 330 ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); 331 if (ioctl(fd, DM_DEV_REMOVE, io)) { 332 SLOGE("Cannot remove dm-crypt device\n"); 333 goto errout; 334 } 335 336 /* We made it here with no errors. Woot! */ 337 retval = 0; 338 339errout: 340 close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ 341 342 return retval; 343 344} 345 346/* If we need to debug this, look at Devmapper.cpp:dumpState(), 347 * It does DM_LIST_DEVICES, then iterates on each device and 348 * calls DM_DEV_STATUS. 349 */ 350 351#define HASH_COUNT 2000 352#define KEY_LEN_BYTES 16 353#define IV_LEN_BYTES 16 354 355static int create_encrypted_random_key(char *passwd, unsigned char *master_key) 356{ 357 int fd; 358 unsigned char buf[KEY_LEN_BYTES]; 359 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 360 unsigned char salt[32] = { 0 }; 361 EVP_CIPHER_CTX e_ctx; 362 int encrypted_len, final_len; 363 364 /* Get some random bits for a key */ 365 fd = open("/dev/urandom", O_RDONLY); 366 read(fd, buf, sizeof(buf)); 367 close(fd); 368 369 /* Now encrypt it with the password */ 370 /* To Do: Make a salt based on some immutable data about this device. 371 * IMEI, or MEID, or CPU serial number, or whatever we can find 372 */ 373 /* Turn the password into a key and IV that can decrypt the master key */ 374 PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, sizeof(salt), 375 HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); 376 377 /* Initialize the decryption engine */ 378 if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 379 SLOGE("EVP_EncryptInit failed\n"); 380 return -1; 381 } 382 EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ 383 /* Encrypt the master key */ 384 if (! EVP_EncryptUpdate(&e_ctx, master_key, &encrypted_len, 385 buf, KEY_LEN_BYTES)) { 386 SLOGE("EVP_EncryptUpdate failed\n"); 387 return -1; 388 } 389 if (! EVP_EncryptFinal(&e_ctx, master_key + encrypted_len, &final_len)) { 390 SLOGE("EVP_EncryptFinal failed\n"); 391 return -1; 392 } 393 394 if (encrypted_len + final_len != KEY_LEN_BYTES) { 395 SLOGE("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); 396 return -1; 397 } else { 398 return 0; 399 } 400} 401 402static int decrypt_master_key(char *passwd, unsigned char *encrypted_master_key, 403 unsigned char *decrypted_master_key) 404{ 405 unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ 406 unsigned char salt[32] = { 0 }; 407 EVP_CIPHER_CTX d_ctx; 408 int decrypted_len, final_len; 409 410 /* To Do: Make a salt based on some immutable data about this device. 411 * IMEI, or MEID, or CPU serial number, or whatever we can find 412 */ 413 /* Turn the password into a key and IV that can decrypt the master key */ 414 PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, sizeof(salt), 415 HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); 416 417 /* Initialize the decryption engine */ 418 if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { 419 return -1; 420 } 421 EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ 422 /* Decrypt the master key */ 423 if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, 424 encrypted_master_key, KEY_LEN_BYTES)) { 425 return -1; 426 } 427 if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { 428 return -1; 429 } 430 431 if (decrypted_len + final_len != KEY_LEN_BYTES) { 432 return -1; 433 } else { 434 return 0; 435 } 436} 437 438static int get_orig_mount_parms(char *mount_point, char *fs_type, char *real_blkdev, 439 unsigned long *mnt_flags, char *fs_options) 440{ 441 char mount_point2[32]; 442 char fs_flags[32]; 443 444 property_get("ro.crypto.fs_type", fs_type, ""); 445 property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); 446 property_get("ro.crypto.fs_mnt_point", mount_point2, ""); 447 property_get("ro.crypto.fs_options", fs_options, ""); 448 property_get("ro.crypto.fs_flags", fs_flags, ""); 449 *mnt_flags = strtol(fs_flags, 0, 0); 450 451 if (strcmp(mount_point, mount_point2)) { 452 /* Consistency check. These should match. If not, something odd happened. */ 453 return -1; 454 } 455 456 return 0; 457} 458 459static int wait_and_unmount(char *mountpoint) 460{ 461 int i, rc; 462#define WAIT_UNMOUNT_COUNT 20 463 464 /* Now umount the tmpfs filesystem */ 465 for (i=0; i<WAIT_UNMOUNT_COUNT; i++) { 466 if (umount(mountpoint)) { 467 sleep(1); 468 i++; 469 } else { 470 break; 471 } 472 } 473 474 if (i < WAIT_UNMOUNT_COUNT) { 475 SLOGD("unmounting %s succeeded\n", mountpoint); 476 rc = 0; 477 } else { 478 SLOGE("unmounting %s failed\n", mountpoint); 479 rc = -1; 480 } 481 482 return rc; 483} 484 485int cryptfs_restart(void) 486{ 487 char fs_type[32]; 488 char real_blkdev[MAXPATHLEN]; 489 char crypto_blkdev[MAXPATHLEN]; 490 char fs_options[256]; 491 unsigned long mnt_flags; 492 struct stat statbuf; 493 int rc = -1, i; 494#define DATA_PREP_TIMEOUT 100 495 496 /* Here is where we shut down the framework. The init scripts 497 * start all services in one of three classes: core, main or late_start. 498 * On boot, we start core and main. Now, we stop main, but not core, 499 * as core includes vold and a few other really important things that 500 * we need to keep running. Once main has stopped, we should be able 501 * to umount the tmpfs /data, then mount the encrypted /data. 502 * We then restart the class main, and also the class late_start. 503 * At the moment, I've only put a few things in late_start that I know 504 * are not needed to bring up the framework, and that also cause problems 505 * with unmounting the tmpfs /data, but I hope to add add more services 506 * to the late_start class as we optimize this to decrease the delay 507 * till the user is asked for the password to the filesystem. 508 */ 509 510 /* The init files are setup to stop the class main when vold.decrypt is 511 * set to trigger_reset_main. 512 */ 513 property_set("vold.decrypt", "trigger_reset_main"); 514 SLOGD("Just asked init to shut down class main\n"); 515 516 /* Now that the framework is shutdown, we should be able to umount() 517 * the tmpfs filesystem, and mount the real one. 518 */ 519 520 property_get("ro.crypto.fs_crypto_blkdev", crypto_blkdev, ""); 521 if (strlen(crypto_blkdev) == 0) { 522 SLOGE("fs_crypto_blkdev not set\n"); 523 return -1; 524 } 525 526 if (! get_orig_mount_parms("/data", fs_type, real_blkdev, &mnt_flags, fs_options)) { 527 SLOGD("Just got orig mount parms\n"); 528 529 if (! (rc = wait_and_unmount("/data")) ) { 530 /* If that succeeded, then mount the decrypted filesystem */ 531 mount(crypto_blkdev, "/data", fs_type, mnt_flags, fs_options); 532 533 /* Do the prep of the /data filesystem */ 534 property_set("vold.post_fs_data_done", "0"); 535 property_set("vold.decrypt", "trigger_post_fs_data"); 536 SLOGD("Just triggered post_fs_data\n"); 537 538 /* Wait a max of 25 seconds, hopefully it takes much less */ 539 for (i=0; i<DATA_PREP_TIMEOUT; i++) { 540 char p[16];; 541 542 property_get("vold.post_fs_data_done", p, "0"); 543 if (*p == '1') { 544 break; 545 } else { 546 usleep(250000); 547 } 548 } 549 if (i == DATA_PREP_TIMEOUT) { 550 /* Ugh, we failed to prep /data in time. Bail. */ 551 return -1; 552 } 553 554 /* startup service classes main and late_start */ 555 property_set("vold.decrypt", "trigger_restart_framework"); 556 SLOGD("Just triggered restart_framework\n"); 557 558 /* Give it a few moments to get started */ 559 sleep(1); 560 } 561 } 562 563 return rc; 564} 565 566static int test_mount_encrypted_fs(char *passwd, char *mount_point) 567{ 568 struct crypt_mnt_ftr crypt_ftr; 569 /* Allocate enough space for a 256 bit key, but we may use less */ 570 unsigned char encrypted_master_key[32], decrypted_master_key[32]; 571 char crypto_blkdev[MAXPATHLEN]; 572 char real_blkdev[MAXPATHLEN]; 573 char fs_type[32]; 574 char fs_options[256]; 575 char tmp_mount_point[64]; 576 unsigned long mnt_flags; 577 unsigned int orig_failed_decrypt_count; 578 int rc; 579 580 if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { 581 SLOGE("Error reading original mount parms for mount point %s\n", mount_point); 582 return -1; 583 } 584 585 if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key)) { 586 SLOGE("Error getting crypt footer and key\n"); 587 return -1; 588 } 589 SLOGD("crypt_ftr->fs_size = %lld\n", crypt_ftr.fs_size); 590 orig_failed_decrypt_count = crypt_ftr.failed_decrypt_count; 591 592 if (! (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { 593 decrypt_master_key(passwd, encrypted_master_key, decrypted_master_key); 594 } 595 596 if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, 597 real_blkdev, crypto_blkdev)) { 598 SLOGE("Error creating decrypted block device\n"); 599 return -1; 600 } 601 602 /* If init detects an encrypted filesystme, it writes a file for each such 603 * encrypted fs into the tmpfs /data filesystem, and then the framework finds those 604 * files and passes that data to me */ 605 /* Create a tmp mount point to try mounting the decryptd fs 606 * Since we're here, the mount_point should be a tmpfs filesystem, so make 607 * a directory in it to test mount the decrypted filesystem. 608 */ 609 sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); 610 mkdir(tmp_mount_point, 0755); 611 if ( mount(crypto_blkdev, tmp_mount_point, "ext4", MS_RDONLY, "") ) { 612 SLOGE("Error temp mounting decrypted block device\n"); 613 delete_crypto_blk_dev(crypto_blkdev); 614 crypt_ftr.failed_decrypt_count++; 615 } else { 616 /* Success, so just umount and we'll mount it properly when we restart 617 * the framework. 618 */ 619 umount(tmp_mount_point); 620 crypt_ftr.failed_decrypt_count = 0; 621 } 622 623 if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) { 624 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0); 625 } 626 627 if (crypt_ftr.failed_decrypt_count) { 628 /* We failed to mount the device, so return an error */ 629 rc = crypt_ftr.failed_decrypt_count; 630 631 } else { 632 /* Woot! Success! Save the name of the crypto block device 633 * so we can mount it when restarting the framework. 634 */ 635 property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); 636 rc = 0; 637 } 638 639 return rc; 640} 641 642int cryptfs_check_passwd(char *passwd) 643{ 644 int rc = -1; 645 646 rc = test_mount_encrypted_fs(passwd, "/data"); 647 648 return rc; 649} 650 651/* Initialize a crypt_mnt_ftr structure. The keysize is 652 * defaulted to 16 bytes, and the filesystem size to 0. 653 * Presumably, at a minimum, the caller will update the 654 * filesystem size and crypto_type_name after calling this function. 655 */ 656static void cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) 657{ 658 ftr->magic = CRYPT_MNT_MAGIC; 659 ftr->major_version = 1; 660 ftr->minor_version = 0; 661 ftr->ftr_size = sizeof(struct crypt_mnt_ftr); 662 ftr->flags = 0; 663 ftr->keysize = 16; 664 ftr->spare1 = 0; 665 ftr->fs_size = 0; 666 ftr->failed_decrypt_count = 0; 667 ftr->crypto_type_name[0] = '\0'; 668} 669 670static int cryptfs_enable_wipe(char *crypto_blkdev, off64_t size) 671{ 672 char cmdline[256]; 673 int rc = -1; 674 675 snprintf(cmdline, sizeof(cmdline), "/system/bin/make_ext4fs -a /data -l %lld %s", 676 size * 512, crypto_blkdev); 677 SLOGI("Making empty filesystem with command %s\n", cmdline); 678 if (system(cmdline)) { 679 SLOGE("Error creating empty filesystem on %s\n", crypto_blkdev); 680 } else { 681 SLOGD("Successfully created empty filesystem on %s\n", crypto_blkdev); 682 rc = 0; 683 } 684 685 return rc; 686} 687 688static inline int unix_read(int fd, void* buff, int len) 689{ 690 int ret; 691 do { ret = read(fd, buff, len); } while (ret < 0 && errno == EINTR); 692 return ret; 693} 694 695static inline int unix_write(int fd, const void* buff, int len) 696{ 697 int ret; 698 do { ret = write(fd, buff, len); } while (ret < 0 && errno == EINTR); 699 return ret; 700} 701 702#define CRYPT_INPLACE_BUFSIZE 4096 703#define CRYPT_SECTORS_PER_BUFSIZE (CRYPT_INPLACE_BUFSIZE / 512) 704static int cryptfs_enable_inplace(char *crypto_blkdev, char *real_blkdev, off64_t size) 705{ 706 int realfd, cryptofd; 707 char *buf[CRYPT_INPLACE_BUFSIZE]; 708 int rc = -1; 709 off64_t numblocks, i, remainder; 710 711 if ( (realfd = open(real_blkdev, O_RDONLY)) < 0) { 712 SLOGE("Error opening real_blkdev %s for inplace encrypt\n", real_blkdev); 713 return -1; 714 } 715 716 if ( (cryptofd = open(crypto_blkdev, O_WRONLY)) < 0) { 717 SLOGE("Error opening crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 718 close(realfd); 719 return -1; 720 } 721 722 /* This is pretty much a simple loop of reading 4K, and writing 4K. 723 * The size passed in is the number of 512 byte sectors in the filesystem. 724 * So compute the number of whole 4K blocks we should read/write, 725 * and the remainder. 726 */ 727 numblocks = size / CRYPT_SECTORS_PER_BUFSIZE; 728 remainder = size % CRYPT_SECTORS_PER_BUFSIZE; 729 730 SLOGE("Encrypting filesystem in place..."); 731 732 /* process the majority of the filesystem in blocks */ 733 for (i=0; i<numblocks; i++) { 734 if ( ! (i % 65536)) { //KEN 735 SLOGE("|"); //KEN 736 } //KEN 737 if (unix_read(realfd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 738 SLOGE("Error reading real_blkdev %s for inplace encrypt\n", crypto_blkdev); 739 goto errout; 740 } 741 if (unix_write(cryptofd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { 742 SLOGE("Error writing crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 743 goto errout; 744 } 745 } 746 747 /* Do any remaining sectors */ 748 for (i=0; i<remainder; i++) { 749 if (unix_read(realfd, buf, 512) <= 0) { 750 SLOGE("Error reading rival sectors from real_blkdev %s for inplace encrypt\n", crypto_blkdev); 751 goto errout; 752 } 753 if (unix_write(cryptofd, buf, 512) <= 0) { 754 SLOGE("Error writing final sectors to crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); 755 goto errout; 756 } 757 } 758 759 rc = 0; 760 761errout: 762 close(realfd); 763 close(cryptofd); 764 765 return rc; 766} 767 768#define CRYPTO_ENABLE_WIPE 1 769#define CRYPTO_ENABLE_INPLACE 2 770int cryptfs_enable(char *howarg, char *passwd) 771{ 772 int how = 0; 773 char crypto_blkdev[MAXPATHLEN], real_blkdev[MAXPATHLEN]; 774 char fs_type[32], fs_options[256], mount_point[32]; 775 unsigned long mnt_flags, nr_sec; 776 unsigned char master_key[16], decrypted_master_key[16]; 777 int rc, fd; 778 struct crypt_mnt_ftr crypt_ftr; 779 780 if (!strcmp(howarg, "wipe")) { 781 how = CRYPTO_ENABLE_WIPE; 782 } else if (! strcmp(howarg, "inplace")) { 783 how = CRYPTO_ENABLE_INPLACE; 784 } else { 785 /* Shouldn't happen, as CommandListener vets the args */ 786 return -1; 787 } 788 789 get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options); 790 791 /* The init files are setup to stop the class main and late start when 792 * set to 4. They also unmount the fuse filesystem /mnt/sdcard on stingray. 793 */ 794 property_set("vold.decrypt", "trigger_shutdown_framework"); 795 SLOGD("Just asked init to shut down class main\n"); 796 797 if (wait_and_unmount("/mnt/sdcard")) { 798 return -1; 799 } 800 801 /* Now unmount the /data partition. */ 802 if (! (rc = wait_and_unmount("/data")) ) { 803 /* OK, we've unmounted /data, time to setup an encrypted 804 * mapping, and either write a new filesystem or encrypt 805 * in place. 806 */ 807 808 fd = open(real_blkdev, O_RDONLY); 809 if ( (nr_sec = get_blkdev_size(fd)) == 0) { 810 SLOGE("Cannot get size of block device %s\n", real_blkdev); 811 return -1; 812 } 813 close(fd); 814 815 /* Initialize a crypt_mnt_ftr for the partition */ 816 cryptfs_init_crypt_mnt_ftr(&crypt_ftr); 817 crypt_ftr.fs_size = nr_sec - (CRYPT_FOOTER_OFFSET / 512); 818 strcpy((char *)crypt_ftr.crypto_type_name, "aes-cbc-essiv:sha256"); 819 820 /* Make an encrypted master key */ 821 if (create_encrypted_random_key(passwd, master_key)) { 822 SLOGE("Cannot create encrypted master key\n"); 823 return -1; 824 } 825 826 /* Write the key to the end of the partition */ 827 put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, master_key); 828 829 decrypt_master_key(passwd, master_key, decrypted_master_key); 830 create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, real_blkdev, crypto_blkdev); 831 832 if (how == CRYPTO_ENABLE_WIPE) { 833 rc = cryptfs_enable_wipe(crypto_blkdev, crypt_ftr.fs_size); 834 } else if (how == CRYPTO_ENABLE_INPLACE) { 835 rc = cryptfs_enable_inplace(crypto_blkdev, real_blkdev, crypt_ftr.fs_size); 836 } else { 837 /* Shouldn't happen */ 838 SLOGE("cryptfs_enable: internal error, unknown option\n"); 839 return -1; 840 } 841 842 if (! rc) { 843 delete_crypto_blk_dev(crypto_blkdev); 844 sync(); 845 reboot(LINUX_REBOOT_CMD_RESTART); 846 } 847 } else { 848 return -1; 849 } 850 851 return 0; 852} 853 854