1 files changed, 1164 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;
+}