diff options
Diffstat (limited to '')
| -rw-r--r-- | crypto/ics/cryptfs.c | 1164 | ||||
| -rw-r--r-- | crypto/ics/cryptfs.h | 89 |
2 files changed, 1253 insertions, 0 deletions
diff --git a/crypto/ics/cryptfs.c b/crypto/ics/cryptfs.c new file mode 100644 index 000000000..054036628 --- /dev/null +++ b/crypto/ics/cryptfs.c @@ -0,0 +1,1164 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* TO DO: + * 1. Perhaps keep several copies of the encrypted key, in case something + * goes horribly wrong? + * + */ + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <stdio.h> +#include <sys/ioctl.h> +#include <linux/dm-ioctl.h> +#include <libgen.h> +#include <stdlib.h> +#include <sys/param.h> +#include <string.h> +#include <sys/mount.h> +#include <openssl/evp.h> +#include <openssl/sha.h> +#include <errno.h> +#include <cutils/android_reboot.h> +#include <ext4.h> +#include <linux/kdev_t.h> +#include "cryptfs.h" +#define LOG_TAG "Cryptfs" +#include "cutils/log.h" +#include "cutils/properties.h" +#include "hardware_legacy/power.h" +//#include "VolumeManager.h" + +#define DM_CRYPT_BUF_SIZE 4096 +#define DATA_MNT_POINT "/data" + +#define HASH_COUNT 2000 +#define KEY_LEN_BYTES 16 +#define IV_LEN_BYTES 16 + +#define KEY_LOC_PROP "ro.crypto.keyfile.userdata" +#define KEY_IN_FOOTER "footer" + +#define EXT4_FS 1 +#define FAT_FS 2 + +char *me = "cryptfs"; + +static unsigned char saved_master_key[KEY_LEN_BYTES]; +static char *saved_data_blkdev; +static char *saved_mount_point; +static int master_key_saved = 0; + +static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) +{ + memset(io, 0, dataSize); + io->data_size = dataSize; + io->data_start = sizeof(struct dm_ioctl); + io->version[0] = 4; + io->version[1] = 0; + io->version[2] = 0; + io->flags = flags; + if (name) { + strncpy(io->name, name, sizeof(io->name)); + } +} + +static unsigned int get_fs_size(char *dev) +{ + int fd, block_size; + struct ext4_super_block sb; + off64_t len; + + if ((fd = open(dev, O_RDONLY)) < 0) { + SLOGE("Cannot open device to get filesystem size "); + return 0; + } + + if (lseek64(fd, 1024, SEEK_SET) < 0) { + SLOGE("Cannot seek to superblock"); + return 0; + } + + if (read(fd, &sb, sizeof(sb)) != sizeof(sb)) { + SLOGE("Cannot read superblock"); + return 0; + } + + close(fd); + + block_size = 1024 << sb.s_log_block_size; + /* compute length in bytes */ + len = ( ((off64_t)sb.s_blocks_count_hi << 32) + sb.s_blocks_count_lo) * block_size; + + /* return length in sectors */ + return (unsigned int) (len / 512); +} + +static unsigned int get_blkdev_size(int fd) +{ + unsigned int nr_sec; + + if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { + nr_sec = 0; + } + + return nr_sec; +} + +/* key or salt can be NULL, in which case just skip writing that value. Useful to + * update the failed mount count but not change the key. + */ +static int put_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, + unsigned char *key, unsigned char *salt) +{ + int fd; + unsigned int nr_sec, cnt; + off64_t off; + int rc = -1; + char *fname; + char key_loc[PROPERTY_VALUE_MAX]; + struct stat statbuf; + + property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); + + if (!strcmp(key_loc, KEY_IN_FOOTER)) { + fname = real_blk_name; + if ( (fd = open(fname, O_RDWR)) < 0) { + SLOGE("Cannot open real block device %s\n", fname); + return -1; + } + + if ( (nr_sec = get_blkdev_size(fd)) == 0) { + SLOGE("Cannot get size of block device %s\n", fname); + goto errout; + } + + /* If it's an encrypted Android partition, the last 16 Kbytes contain the + * encryption info footer and key, and plenty of bytes to spare for future + * growth. + */ + off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; + + if (lseek64(fd, off, SEEK_SET) == -1) { + SLOGE("Cannot seek to real block device footer\n"); + goto errout; + } + } else if (key_loc[0] == '/') { + fname = key_loc; + if ( (fd = open(fname, O_RDWR | O_CREAT, 0600)) < 0) { + SLOGE("Cannot open footer file %s\n", fname); + return -1; + } + } else { + SLOGE("Unexpected value for" KEY_LOC_PROP "\n"); + return -1;; + } + + if ((cnt = write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { + SLOGE("Cannot write real block device footer\n"); + goto errout; + } + + if (key) { + if (crypt_ftr->keysize != KEY_LEN_BYTES) { + SLOGE("Keysize of %d bits not supported for real block device %s\n", + crypt_ftr->keysize*8, fname); + goto errout; + } + + if ( (cnt = write(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { + SLOGE("Cannot write key for real block device %s\n", fname); + goto errout; + } + } + + if (salt) { + /* Compute the offset from the last write to the salt */ + off = KEY_TO_SALT_PADDING; + if (! key) + off += crypt_ftr->keysize; + + if (lseek64(fd, off, SEEK_CUR) == -1) { + SLOGE("Cannot seek to real block device salt \n"); + goto errout; + } + + if ( (cnt = write(fd, salt, SALT_LEN)) != SALT_LEN) { + SLOGE("Cannot write salt for real block device %s\n", fname); + goto errout; + } + } + + fstat(fd, &statbuf); + /* If the keys are kept on a raw block device, do not try to truncate it. */ + if (S_ISREG(statbuf.st_mode) && (key_loc[0] == '/')) { + if (ftruncate(fd, 0x4000)) { + SLOGE("Cannot set footer file size\n", fname); + goto errout; + } + } + + /* Success! */ + rc = 0; + +errout: + close(fd); + return rc; + +} + +static int get_crypt_ftr_and_key(char *real_blk_name, struct crypt_mnt_ftr *crypt_ftr, + unsigned char *key, unsigned char *salt) +{ + int fd; + unsigned int nr_sec, cnt; + off64_t off; + int rc = -1; + char key_loc[PROPERTY_VALUE_MAX]; + char *fname; + struct stat statbuf; + + property_get(KEY_LOC_PROP, key_loc, KEY_IN_FOOTER); + + if (!strcmp(key_loc, KEY_IN_FOOTER)) { + fname = real_blk_name; + if ( (fd = open(fname, O_RDONLY)) < 0) { + ui_print("Cannot open real block device %s\n", fname); + return -1; + } + + if ( (nr_sec = get_blkdev_size(fd)) == 0) { + SLOGE("Cannot get size of block device %s\n", fname); + goto errout; + } + + /* If it's an encrypted Android partition, the last 16 Kbytes contain the + * encryption info footer and key, and plenty of bytes to spare for future + * growth. + */ + off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; + + if (lseek64(fd, off, SEEK_SET) == -1) { + ui_print("Cannot seek to real block device footer\n"); + goto errout; + } + } else if (key_loc[0] == '/') { + fname = key_loc; + if ( (fd = open(fname, O_RDONLY)) < 0) { + ui_print("Cannot open footer file %s\n", fname); + return -1; + } + + /* Make sure it's 16 Kbytes in length */ + fstat(fd, &statbuf); + if (S_ISREG(statbuf.st_mode) && (statbuf.st_size != 0x4000)) { + ui_print("footer file %s is not the expected size!\n", fname); + goto errout; + } + } else { + ui_print("Unexpected value for" KEY_LOC_PROP "\n"); + return -1;; + } + + if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { + ui_print("Cannot read real block device footer\n"); + goto errout; + } + + if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { + ui_print("Bad magic for real block device %s\n", fname); + goto errout; + } + + if (crypt_ftr->major_version != 1) { + ui_print("Cannot understand major version %d real block device footer\n", + crypt_ftr->major_version); + goto errout; + } + + if (crypt_ftr->minor_version != 0) { + ui_print("Warning: crypto footer minor version %d, expected 0, continuing...\n", + crypt_ftr->minor_version); + } + + if (crypt_ftr->ftr_size > sizeof(struct crypt_mnt_ftr)) { + /* the footer size is bigger than we expected. + * Skip to it's stated end so we can read the key. + */ + if (lseek(fd, crypt_ftr->ftr_size - sizeof(struct crypt_mnt_ftr), SEEK_CUR) == -1) { + ui_print("Cannot seek to start of key\n"); + goto errout; + } + } + + if (crypt_ftr->keysize != KEY_LEN_BYTES) { + ui_print("Keysize of %d bits not supported for real block device %s\n", + crypt_ftr->keysize * 8, fname); + goto errout; + } + + if ( (cnt = read(fd, key, crypt_ftr->keysize)) != crypt_ftr->keysize) { + ui_print("Cannot read key for real block device %s\n", fname); + goto errout; + } + + if (lseek64(fd, KEY_TO_SALT_PADDING, SEEK_CUR) == -1) { + ui_print("Cannot seek to real block device salt\n"); + goto errout; + } + + if ( (cnt = read(fd, salt, SALT_LEN)) != SALT_LEN) { + ui_print("Cannot read salt for real block device %s\n", fname); + goto errout; + } + + /* Success! */ + rc = 0; + +errout: + close(fd); + return rc; +} + +/* Convert a binary key of specified length into an ascii hex string equivalent, + * without the leading 0x and with null termination + */ +void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, + char *master_key_ascii) +{ + unsigned int i, a; + unsigned char nibble; + + for (i=0, a=0; i<keysize; i++, a+=2) { + /* For each byte, write out two ascii hex digits */ + nibble = (master_key[i] >> 4) & 0xf; + master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); + + nibble = master_key[i] & 0xf; + master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); + } + + /* Add the null termination */ + master_key_ascii[a] = '\0'; + +} + +static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, + char *real_blk_name, char *crypto_blk_name, const char *name) +{ + char buffer[DM_CRYPT_BUF_SIZE]; + char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ + char *crypt_params; + struct dm_ioctl *io; + struct dm_target_spec *tgt; + unsigned int minor; + int fd; + int retval = -1; + + if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { + ui_print("Cannot open device-mapper\n"); + goto errout; + } + + io = (struct dm_ioctl *) buffer; + + ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); + if (ioctl(fd, DM_DEV_CREATE, io)) { + ui_print("Cannot create dm-crypt device\n"); + goto errout; + } + + /* Get the device status, in particular, the name of it's device file */ + ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); + if (ioctl(fd, DM_DEV_STATUS, io)) { + ui_print("Cannot retrieve dm-crypt device status\n"); + goto errout; + } + minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); + snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); + + /* Load the mapping table for this device */ + tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; + + ioctl_init(io, 4096, name, 0); + io->target_count = 1; + tgt->status = 0; + tgt->sector_start = 0; + tgt->length = crypt_ftr->fs_size; + strcpy(tgt->target_type, "crypt"); + + crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); + convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); + sprintf(crypt_params, "%s %s 0 %s 0", crypt_ftr->crypto_type_name, + master_key_ascii, real_blk_name); + crypt_params += strlen(crypt_params) + 1; + crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ + tgt->next = crypt_params - buffer; + + if (ioctl(fd, DM_TABLE_LOAD, io)) { + ui_print("Cannot load dm-crypt mapping table.\n"); + goto errout; + } + + /* Resume this device to activate it */ + ioctl_init(io, 4096, name, 0); + + if (ioctl(fd, DM_DEV_SUSPEND, io)) { + ui_print("Cannot resume the dm-crypt device\n"); + goto errout; + } + + /* We made it here with no errors. Woot! */ + retval = 0; + +errout: + close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ + + return retval; +} + +static int delete_crypto_blk_dev(char *name) +{ + int fd; + char buffer[DM_CRYPT_BUF_SIZE]; + struct dm_ioctl *io; + int retval = -1; + + if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { + ui_print("Cannot open device-mapper\n"); + goto errout; + } + + io = (struct dm_ioctl *) buffer; + + ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); + if (ioctl(fd, DM_DEV_REMOVE, io)) { + ui_print("Cannot remove dm-crypt device\n"); + goto errout; + } + + /* We made it here with no errors. Woot! */ + retval = 0; + +errout: + close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ + + return retval; + +} + +static void pbkdf2(char *passwd, unsigned char *salt, unsigned char *ikey) +{ + /* Turn the password into a key and IV that can decrypt the master key */ + PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN, + HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); +} + +static int encrypt_master_key(char *passwd, unsigned char *salt, + unsigned char *decrypted_master_key, + unsigned char *encrypted_master_key) +{ + unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ + EVP_CIPHER_CTX e_ctx; + int encrypted_len, final_len; + + /* Turn the password into a key and IV that can decrypt the master key */ + pbkdf2(passwd, salt, ikey); + + /* Initialize the decryption engine */ + if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { + SLOGE("EVP_EncryptInit failed\n"); + return -1; + } + EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ + + /* Encrypt the master key */ + if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len, + decrypted_master_key, KEY_LEN_BYTES)) { + SLOGE("EVP_EncryptUpdate failed\n"); + return -1; + } + if (! EVP_EncryptFinal(&e_ctx, encrypted_master_key + encrypted_len, &final_len)) { + SLOGE("EVP_EncryptFinal failed\n"); + return -1; + } + + if (encrypted_len + final_len != KEY_LEN_BYTES) { + SLOGE("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); + return -1; + } else { + return 0; + } +} + +static int decrypt_master_key(char *passwd, unsigned char *salt, + unsigned char *encrypted_master_key, + unsigned char *decrypted_master_key) +{ + unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ + EVP_CIPHER_CTX d_ctx; + int decrypted_len, final_len; + + /* Turn the password into a key and IV that can decrypt the master key */ + pbkdf2(passwd, salt, ikey); + + /* Initialize the decryption engine */ + if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { + return -1; + } + EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ + /* Decrypt the master key */ + if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, + encrypted_master_key, KEY_LEN_BYTES)) { + return -1; + } + if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { + return -1; + } + + if (decrypted_len + final_len != KEY_LEN_BYTES) { + return -1; + } else { + return 0; + } +} + +static int create_encrypted_random_key(char *passwd, unsigned char *master_key, unsigned char *salt) +{ + int fd; + unsigned char key_buf[KEY_LEN_BYTES]; + EVP_CIPHER_CTX e_ctx; + int encrypted_len, final_len; + + /* Get some random bits for a key */ + fd = open("/dev/urandom", O_RDONLY); + read(fd, key_buf, sizeof(key_buf)); + read(fd, salt, SALT_LEN); + close(fd); + + /* Now encrypt it with the password */ + return encrypt_master_key(passwd, salt, key_buf, master_key); +} + +static int get_orig_mount_parms(char *mount_point, char *fs_type, char *real_blkdev, + unsigned long *mnt_flags, char *fs_options) +{ + char mount_point2[PROPERTY_VALUE_MAX]; + char fs_flags[PROPERTY_VALUE_MAX]; + + property_get("ro.crypto.fs_type", fs_type, ""); + property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); + property_get("ro.crypto.fs_mnt_point", mount_point2, ""); + property_get("ro.crypto.fs_options", fs_options, ""); + property_get("ro.crypto.fs_flags", fs_flags, ""); + *mnt_flags = strtol(fs_flags, 0, 0); + + if (strcmp(mount_point, mount_point2)) { + /* Consistency check. These should match. If not, something odd happened. */ + return -1; + } + + return 0; +} + +static int wait_and_unmount(char *mountpoint) +{ + int i, rc; +#define WAIT_UNMOUNT_COUNT 20 + + /* Now umount the tmpfs filesystem */ + for (i=0; i<WAIT_UNMOUNT_COUNT; i++) { + if (umount(mountpoint)) { + if (errno == EINVAL) { + /* EINVAL is returned if the directory is not a mountpoint, + * i.e. there is no filesystem mounted there. So just get out. + */ + break; + } + sleep(1); + i++; + } else { + break; + } + } + + if (i < WAIT_UNMOUNT_COUNT) { + SLOGD("unmounting %s succeeded\n", mountpoint); + rc = 0; + } else { + SLOGE("unmounting %s failed\n", mountpoint); + rc = -1; + } + + return rc; +} + +#define DATA_PREP_TIMEOUT 100 +static int prep_data_fs(void) +{ + int i; + + /* Do the prep of the /data filesystem */ + property_set("vold.post_fs_data_done", "0"); + property_set("vold.decrypt", "trigger_post_fs_data"); + SLOGD("Just triggered post_fs_data\n"); + + /* Wait a max of 25 seconds, hopefully it takes much less */ + for (i=0; i<DATA_PREP_TIMEOUT; i++) { + char p[PROPERTY_VALUE_MAX]; + + property_get("vold.post_fs_data_done", p, "0"); + if (*p == '1') { + break; + } else { + usleep(250000); + } + } + if (i == DATA_PREP_TIMEOUT) { + /* Ugh, we failed to prep /data in time. Bail. */ + return -1; + } else { + SLOGD("post_fs_data done\n"); + return 0; + } +} + +int cryptfs_restart(void) +{ + char fs_type[32]; + char real_blkdev[MAXPATHLEN]; + char crypto_blkdev[MAXPATHLEN]; + char fs_options[256]; + unsigned long mnt_flags; + struct stat statbuf; + int rc = -1, i; + static int restart_successful = 0; + + /* Validate that it's OK to call this routine */ + if (! master_key_saved) { + SLOGE("Encrypted filesystem not validated, aborting"); + return -1; + } + + if (restart_successful) { + SLOGE("System already restarted with encrypted disk, aborting"); + return -1; + } + + /* Here is where we shut down the framework. The init scripts + * start all services in one of three classes: core, main or late_start. + * On boot, we start core and main. Now, we stop main, but not core, + * as core includes vold and a few other really important things that + * we need to keep running. Once main has stopped, we should be able + * to umount the tmpfs /data, then mount the encrypted /data. + * We then restart the class main, and also the class late_start. + * At the moment, I've only put a few things in late_start that I know + * are not needed to bring up the framework, and that also cause problems + * with unmounting the tmpfs /data, but I hope to add add more services + * to the late_start class as we optimize this to decrease the delay + * till the user is asked for the password to the filesystem. + */ + + /* The init files are setup to stop the class main when vold.decrypt is + * set to trigger_reset_main. + */ + property_set("vold.decrypt", "trigger_reset_main"); + SLOGD("Just asked init to shut down class main\n"); + + /* Now that the framework is shutdown, we should be able to umount() + * the tmpfs filesystem, and mount the real one. + */ + + property_get("ro.crypto.fs_crypto_blkdev", crypto_blkdev, ""); + if (strlen(crypto_blkdev) == 0) { + SLOGE("fs_crypto_blkdev not set\n"); + return -1; + } + + if (! get_orig_mount_parms(DATA_MNT_POINT, fs_type, real_blkdev, &mnt_flags, fs_options)) { + SLOGD("Just got orig mount parms\n"); + + if (! (rc = wait_and_unmount(DATA_MNT_POINT)) ) { + /* If that succeeded, then mount the decrypted filesystem */ + mount(crypto_blkdev, DATA_MNT_POINT, fs_type, mnt_flags, fs_options); + + property_set("vold.decrypt", "trigger_load_persist_props"); + /* Create necessary paths on /data */ + if (prep_data_fs()) { + return -1; + } + + /* startup service classes main and late_start */ + property_set("vold.decrypt", "trigger_restart_framework"); + SLOGD("Just triggered restart_framework\n"); + + /* Give it a few moments to get started */ + sleep(1); + } + } + + if (rc == 0) { + restart_successful = 1; + } + + return rc; +} + +static int do_crypto_complete(char *mount_point) +{ + struct crypt_mnt_ftr crypt_ftr; + unsigned char encrypted_master_key[32]; + unsigned char salt[SALT_LEN]; + char real_blkdev[MAXPATHLEN]; + char fs_type[PROPERTY_VALUE_MAX]; + char fs_options[PROPERTY_VALUE_MAX]; + unsigned long mnt_flags; + char encrypted_state[PROPERTY_VALUE_MAX]; + + property_get("ro.crypto.state", encrypted_state, ""); + if (strcmp(encrypted_state, "encrypted") ) { + SLOGE("not running with encryption, aborting"); + return 1; + } + + if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { + SLOGE("Error reading original mount parms for mount point %s\n", mount_point); + return -1; + } + + if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { + SLOGE("Error getting crypt footer and key\n"); + return -1; + } + + if (crypt_ftr.flags & CRYPT_ENCRYPTION_IN_PROGRESS) { + SLOGE("Encryption process didn't finish successfully\n"); + return -2; /* -2 is the clue to the UI that there is no usable data on the disk, + * and give the user an option to wipe the disk */ + } + + /* We passed the test! We shall diminish, and return to the west */ + return 0; +} + +static int test_mount_encrypted_fs(char *passwd, char *mount_point, char *label) +{ + struct crypt_mnt_ftr crypt_ftr; + /* Allocate enough space for a 256 bit key, but we may use less */ + unsigned char encrypted_master_key[32], decrypted_master_key[32]; + unsigned char salt[SALT_LEN]; + char crypto_blkdev[MAXPATHLEN]; + char real_blkdev[MAXPATHLEN]; + char fs_type[PROPERTY_VALUE_MAX]; + char fs_options[PROPERTY_VALUE_MAX]; + char tmp_mount_point[64]; + unsigned long mnt_flags; + unsigned int orig_failed_decrypt_count; + char encrypted_state[PROPERTY_VALUE_MAX]; + int rc; + + property_get("ro.crypto.state", encrypted_state, ""); + if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) { + ui_print("encrypted fs already validated or not running with encryption, aborting"); + return -1; + } + + if (get_orig_mount_parms(mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { + ui_print("Error reading original mount parms for mount point %s\n", mount_point); + return -1; + } + + if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { + ui_print("Error getting crypt footer and key\n"); + return -1; + } + + ui_print("crypt_ftr->fs_size = %lld\n", crypt_ftr.fs_size); + orig_failed_decrypt_count = crypt_ftr.failed_decrypt_count; + + if (! (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { + decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); + } + + if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key, + real_blkdev, crypto_blkdev, label)) { + ui_print("Error creating decrypted block device\n"); + return -1; + } + + /* If init detects an encrypted filesystme, it writes a file for each such + * encrypted fs into the tmpfs /data filesystem, and then the framework finds those + * files and passes that data to me */ + /* Create a tmp mount point to try mounting the decryptd fs + * Since we're here, the mount_point should be a tmpfs filesystem, so make + * a directory in it to test mount the decrypted filesystem. + */ + sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); + mkdir(tmp_mount_point, 0755); + if ( mount(crypto_blkdev, tmp_mount_point, "ext4", MS_RDONLY, "") ) { + ui_print("Error temp mounting decrypted block device\n"); + delete_crypto_blk_dev(label); + crypt_ftr.failed_decrypt_count++; + } else { + /* Success, so just umount and we'll mount it properly when we restart + * the framework. + */ + umount(tmp_mount_point); + crypt_ftr.failed_decrypt_count = 0; + } + + if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) { + put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, 0, 0); + } + + if (crypt_ftr.failed_decrypt_count) { + /* We failed to mount the device, so return an error */ + rc = crypt_ftr.failed_decrypt_count; + + } else { + /* Woot! Success! Save the name of the crypto block device + * so we can mount it when restarting the framework. + */ + property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); + + /* Also save a the master key so we can reencrypted the key + * the key when we want to change the password on it. + */ + memcpy(saved_master_key, decrypted_master_key, KEY_LEN_BYTES); + saved_data_blkdev = strdup(real_blkdev); + saved_mount_point = strdup(mount_point); + master_key_saved = 1; + rc = 0; + } + + return rc; +} + +/* Called by vold when it wants to undo the crypto mapping of a volume it + * manages. This is usually in response to a factory reset, when we want + * to undo the crypto mapping so the volume is formatted in the clear. + */ +int cryptfs_revert_volume(const char *label) +{ + return delete_crypto_blk_dev((char *)label); +} + +/* + * Called by vold when it's asked to mount an encrypted, nonremovable volume. + * Setup a dm-crypt mapping, use the saved master key from + * setting up the /data mapping, and return the new device path. + */ +int cryptfs_setup_volume(const char *label, int major, int minor, + char *crypto_sys_path, unsigned int max_path, + int *new_major, int *new_minor) +{ + char real_blkdev[MAXPATHLEN], crypto_blkdev[MAXPATHLEN]; + struct crypt_mnt_ftr sd_crypt_ftr; + unsigned char key[32], salt[32]; + struct stat statbuf; + int nr_sec, fd; + + sprintf(real_blkdev, "/dev/block/vold/%d:%d", major, minor); + + /* Just want the footer, but gotta get it all */ + get_crypt_ftr_and_key(saved_data_blkdev, &sd_crypt_ftr, key, salt); + + /* Update the fs_size field to be the size of the volume */ + fd = open(real_blkdev, O_RDONLY); + nr_sec = get_blkdev_size(fd); + close(fd); + if (nr_sec == 0) { + SLOGE("Cannot get size of volume %s\n", real_blkdev); + return -1; + } + + sd_crypt_ftr.fs_size = nr_sec; + create_crypto_blk_dev(&sd_crypt_ftr, saved_master_key, real_blkdev, + crypto_blkdev, label); + + stat(crypto_blkdev, &statbuf); + *new_major = MAJOR(statbuf.st_rdev); + *new_minor = MINOR(statbuf.st_rdev); + + /* Create path to sys entry for this block device */ + snprintf(crypto_sys_path, max_path, "/devices/virtual/block/%s", strrchr(crypto_blkdev, '/')+1); + + return 0; +} + +int cryptfs_crypto_complete(void) +{ + return do_crypto_complete("/data"); +} + +int cryptfs_check_passwd(char *passwd) +{ + int rc = -1; + + rc = test_mount_encrypted_fs(passwd, DATA_MNT_POINT, "userdata"); + + return rc; +} + +int cryptfs_verify_passwd(char *passwd) +{ + struct crypt_mnt_ftr crypt_ftr; + /* Allocate enough space for a 256 bit key, but we may use less */ + unsigned char encrypted_master_key[32], decrypted_master_key[32]; + unsigned char salt[SALT_LEN]; + char real_blkdev[MAXPATHLEN]; + char fs_type[PROPERTY_VALUE_MAX]; + char fs_options[PROPERTY_VALUE_MAX]; + unsigned long mnt_flags; + char encrypted_state[PROPERTY_VALUE_MAX]; + int rc; + + property_get("ro.crypto.state", encrypted_state, ""); + if (strcmp(encrypted_state, "encrypted") ) { + SLOGE("device not encrypted, aborting"); + return -2; + } + + if (!master_key_saved) { + SLOGE("encrypted fs not yet mounted, aborting"); + return -1; + } + + if (!saved_mount_point) { + SLOGE("encrypted fs failed to save mount point, aborting"); + return -1; + } + + if (get_orig_mount_parms(saved_mount_point, fs_type, real_blkdev, &mnt_flags, fs_options)) { + SLOGE("Error reading original mount parms for mount point %s\n", saved_mount_point); + return -1; + } + + if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { + SLOGE("Error getting crypt footer and key\n"); + return -1; + } + + if (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) { + /* If the device has no password, then just say the password is valid */ + rc = 0; + } else { + decrypt_master_key(passwd, salt, encrypted_master_key, decrypted_master_key); + if (!memcmp(decrypted_master_key, saved_master_key, crypt_ftr.keysize)) { + /* They match, the password is correct */ + rc = 0; + } else { + /* If incorrect, sleep for a bit to prevent dictionary attacks */ + sleep(1); + rc = 1; + } + } + + return rc; +} + +/* Initialize a crypt_mnt_ftr structure. The keysize is + * defaulted to 16 bytes, and the filesystem size to 0. + * Presumably, at a minimum, the caller will update the + * filesystem size and crypto_type_name after calling this function. + */ +static void cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) +{ + ftr->magic = CRYPT_MNT_MAGIC; + ftr->major_version = 1; + ftr->minor_version = 0; + ftr->ftr_size = sizeof(struct crypt_mnt_ftr); + ftr->flags = 0; + ftr->keysize = KEY_LEN_BYTES; + ftr->spare1 = 0; + ftr->fs_size = 0; + ftr->failed_decrypt_count = 0; + ftr->crypto_type_name[0] = '\0'; +} + +static int cryptfs_enable_wipe(char *crypto_blkdev, off64_t size, int type) +{ + char cmdline[256]; + int rc = -1; + + if (type == EXT4_FS) { + snprintf(cmdline, sizeof(cmdline), "/system/bin/make_ext4fs -a /data -l %lld %s", + size * 512, crypto_blkdev); + SLOGI("Making empty filesystem with command %s\n", cmdline); + } else if (type== FAT_FS) { + snprintf(cmdline, sizeof(cmdline), "/system/bin/newfs_msdos -F 32 -O android -c 8 -s %lld %s", + size, crypto_blkdev); + SLOGI("Making empty filesystem with command %s\n", cmdline); + } else { + SLOGE("cryptfs_enable_wipe(): unknown filesystem type %d\n", type); + return -1; + } + + if (system(cmdline)) { + SLOGE("Error creating empty filesystem on %s\n", crypto_blkdev); + } else { + SLOGD("Successfully created empty filesystem on %s\n", crypto_blkdev); + rc = 0; + } + + return rc; +} + +static inline int unix_read(int fd, void* buff, int len) +{ + int ret; + do { ret = read(fd, buff, len); } while (ret < 0 && errno == EINTR); + return ret; +} + +static inline int unix_write(int fd, const void* buff, int len) +{ + int ret; + do { ret = write(fd, buff, len); } while (ret < 0 && errno == EINTR); + return ret; +} + +#define CRYPT_INPLACE_BUFSIZE 4096 +#define CRYPT_SECTORS_PER_BUFSIZE (CRYPT_INPLACE_BUFSIZE / 512) +static int cryptfs_enable_inplace(char *crypto_blkdev, char *real_blkdev, off64_t size, + off64_t *size_already_done, off64_t tot_size) +{ + int realfd, cryptofd; + char *buf[CRYPT_INPLACE_BUFSIZE]; + int rc = -1; + off64_t numblocks, i, remainder; + off64_t one_pct, cur_pct, new_pct; + off64_t blocks_already_done, tot_numblocks; + + if ( (realfd = open(real_blkdev, O_RDONLY)) < 0) { + SLOGE("Error opening real_blkdev %s for inplace encrypt\n", real_blkdev); + return -1; + } + + if ( (cryptofd = open(crypto_blkdev, O_WRONLY)) < 0) { + SLOGE("Error opening crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); + close(realfd); + return -1; + } + + /* This is pretty much a simple loop of reading 4K, and writing 4K. + * The size passed in is the number of 512 byte sectors in the filesystem. + * So compute the number of whole 4K blocks we should read/write, + * and the remainder. + */ + numblocks = size / CRYPT_SECTORS_PER_BUFSIZE; + remainder = size % CRYPT_SECTORS_PER_BUFSIZE; + tot_numblocks = tot_size / CRYPT_SECTORS_PER_BUFSIZE; + blocks_already_done = *size_already_done / CRYPT_SECTORS_PER_BUFSIZE; + + SLOGE("Encrypting filesystem in place..."); + + one_pct = tot_numblocks / 100; + cur_pct = 0; + /* process the majority of the filesystem in blocks */ + for (i=0; i<numblocks; i++) { + new_pct = (i + blocks_already_done) / one_pct; + if (new_pct > cur_pct) { + char buf[8]; + + cur_pct = new_pct; + snprintf(buf, sizeof(buf), "%lld", cur_pct); + property_set("vold.encrypt_progress", buf); + } + if (unix_read(realfd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { + SLOGE("Error reading real_blkdev %s for inplace encrypt\n", crypto_blkdev); + goto errout; + } + if (unix_write(cryptofd, buf, CRYPT_INPLACE_BUFSIZE) <= 0) { + SLOGE("Error writing crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); + goto errout; + } + } + + /* Do any remaining sectors */ + for (i=0; i<remainder; i++) { + if (unix_read(realfd, buf, 512) <= 0) { + SLOGE("Error reading rival sectors from real_blkdev %s for inplace encrypt\n", crypto_blkdev); + goto errout; + } + if (unix_write(cryptofd, buf, 512) <= 0) { + SLOGE("Error writing final sectors to crypto_blkdev %s for inplace encrypt\n", crypto_blkdev); + goto errout; + } + } + + *size_already_done += size; + rc = 0; + +errout: + close(realfd); + close(cryptofd); + + return rc; +} + +#define CRYPTO_ENABLE_WIPE 1 +#define CRYPTO_ENABLE_INPLACE 2 + +#define FRAMEWORK_BOOT_WAIT 60 + +static inline int should_encrypt(struct volume_info *volume) +{ + return (volume->flags & (VOL_ENCRYPTABLE | VOL_NONREMOVABLE)) == + (VOL_ENCRYPTABLE | VOL_NONREMOVABLE); +} + +int cryptfs_enable(char *howarg, char *passwd) +{ + // Code removed because it needs other parts of vold that aren't needed for decryption + return -1; +} + +int cryptfs_changepw(char *newpw) +{ + struct crypt_mnt_ftr crypt_ftr; + unsigned char encrypted_master_key[KEY_LEN_BYTES], decrypted_master_key[KEY_LEN_BYTES]; + unsigned char salt[SALT_LEN]; + char real_blkdev[MAXPATHLEN]; + + /* This is only allowed after we've successfully decrypted the master key */ + if (! master_key_saved) { + SLOGE("Key not saved, aborting"); + return -1; + } + + property_get("ro.crypto.fs_real_blkdev", real_blkdev, ""); + if (strlen(real_blkdev) == 0) { + SLOGE("Can't find real blkdev"); + return -1; + } + + /* get key */ + if (get_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt)) { + SLOGE("Error getting crypt footer and key"); + return -1; + } + + encrypt_master_key(newpw, salt, saved_master_key, encrypted_master_key); + + /* save the key */ + put_crypt_ftr_and_key(real_blkdev, &crypt_ftr, encrypted_master_key, salt); + + return 0; +} diff --git a/crypto/ics/cryptfs.h b/crypto/ics/cryptfs.h new file mode 100644 index 000000000..1c1bc1aea --- /dev/null +++ b/crypto/ics/cryptfs.h @@ -0,0 +1,89 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* This structure starts 16,384 bytes before the end of a hardware + * partition that is encrypted. + * Immediately following this structure is the encrypted key. + * The keysize field tells how long the key is, in bytes. + * Then there is 32 bytes of padding, + * Finally there is the salt used with the user password. + * The salt is fixed at 16 bytes long. + * Obviously, the filesystem does not include the last 16 kbytes + * of the partition. + */ + +#define CRYPT_FOOTER_OFFSET 0x4000 + +#define MAX_CRYPTO_TYPE_NAME_LEN 64 + +#define SALT_LEN 16 +#define KEY_TO_SALT_PADDING 32 + +/* definitions of flags in the structure below */ +#define CRYPT_MNT_KEY_UNENCRYPTED 0x1 /* The key for the partition is not encrypted. */ +#define CRYPT_ENCRYPTION_IN_PROGRESS 0x2 /* Set when starting encryption, + * clear when done before rebooting */ + +#define CRYPT_MNT_MAGIC 0xD0B5B1C4 + +#define __le32 unsigned int +#define __le16 unsigned short int + +struct crypt_mnt_ftr { + __le32 magic; /* See above */ + __le16 major_version; + __le16 minor_version; + __le32 ftr_size; /* in bytes, not including key following */ + __le32 flags; /* See above */ + __le32 keysize; /* in bytes */ + __le32 spare1; /* ignored */ + __le64 fs_size; /* Size of the encrypted fs, in 512 byte sectors */ + __le32 failed_decrypt_count; /* count of # of failed attempts to decrypt and + mount, set to 0 on successful mount */ + unsigned char crypto_type_name[MAX_CRYPTO_TYPE_NAME_LEN]; /* The type of encryption + needed to decrypt this + partition, null terminated */ +}; + +struct volume_info { + unsigned int size; + unsigned int flags; + struct crypt_mnt_ftr crypt_ftr; + char mnt_point[256]; + char blk_dev[256]; + char crypto_blkdev[256]; + char label[256]; +}; +#define VOL_NONREMOVABLE 0x1 +#define VOL_ENCRYPTABLE 0x2 + +#ifdef __cplusplus +extern "C" { +#endif + int cryptfs_crypto_complete(void); + int cryptfs_check_passwd(char *pw); + int cryptfs_verify_passwd(char *newpw); + int cryptfs_restart(void); + int cryptfs_enable(char *flag, char *passwd); + int cryptfs_changepw(char *newpw); + int cryptfs_setup_volume(const char *label, int major, int minor, + char *crypto_dev_path, unsigned int max_pathlen, + int *new_major, int *new_minor); + int cryptfs_revert_volume(const char *label); +#ifdef __cplusplus +} +#endif + |