Support default, pattern, pin and password encryption types
Store encryption type in crypto footer, and provide functions to
manipulate it. Add mount_default_encrypted command to vdc to allow
mounting of default encrypted volumes at boot time.
Bug: 8769627
Change-Id: Ie41848f258e128b48b579e09789abfa24c95e2b2
diff --git a/cryptfs.c b/cryptfs.c
index 40ad36a..4dd7a6b 100644
--- a/cryptfs.c
+++ b/cryptfs.c
@@ -23,6 +23,7 @@
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
+#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
@@ -61,6 +62,9 @@
#define KEY_IN_FOOTER "footer"
+// "default_password" encoded into hex (d=0x64 etc)
+#define DEFAULT_PASSWORD "64656661756c745f70617373776f7264"
+
#define EXT4_FS 1
#define FAT_FS 2
@@ -351,7 +355,7 @@
crypt_ftr->minor_version = 1;
}
- if ((crypt_ftr->major_version == 1) && (crypt_ftr->minor_version)) {
+ if ((crypt_ftr->major_version == 1) && (crypt_ftr->minor_version == 1)) {
SLOGW("upgrading crypto footer to 1.2");
/* But keep the old kdf_type.
* It will get updated later to KDF_SCRYPT after the password has been verified.
@@ -361,6 +365,12 @@
crypt_ftr->minor_version = 2;
}
+ if ((crypt_ftr->major_version == 1) && (crypt_ftr->minor_version == 2)) {
+ SLOGW("upgrading crypto footer to 1.3");
+ crypt_ftr->crypt_type = CRYPT_TYPE_PASSWORD;
+ crypt_ftr->minor_version = 3;
+ }
+
if ((orig_major != crypt_ftr->major_version) || (orig_minor != crypt_ftr->minor_version)) {
if (lseek64(fd, offset, SEEK_SET) == -1) {
SLOGE("Cannot seek to crypt footer\n");
@@ -663,10 +673,53 @@
return -1;
}
+static int hexdigit (char c)
+{
+ if (c >= '0' && c <= '9') return c - '0';
+ c = tolower(c);
+ if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+ return -1;
+}
+
+static unsigned char* convert_hex_ascii_to_key(const char* master_key_ascii,
+ unsigned int* out_keysize)
+{
+ unsigned int i;
+ *out_keysize = 0;
+
+ size_t size = strlen (master_key_ascii);
+ if (size % 2) {
+ SLOGE("Trying to convert ascii string of odd length");
+ return NULL;
+ }
+
+ unsigned char* master_key = (unsigned char*) malloc(size / 2);
+ if (master_key == 0) {
+ SLOGE("Cannot allocate");
+ return NULL;
+ }
+
+ for (i = 0; i < size; i += 2) {
+ int high_nibble = hexdigit (master_key_ascii[i]);
+ int low_nibble = hexdigit (master_key_ascii[i + 1]);
+
+ if(high_nibble < 0 || low_nibble < 0) {
+ SLOGE("Invalid hex string");
+ free (master_key);
+ return NULL;
+ }
+
+ master_key[*out_keysize] = high_nibble * 16 + low_nibble;
+ (*out_keysize)++;
+ }
+
+ return master_key;
+}
+
/* 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,
+static void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize,
char *master_key_ascii)
{
unsigned int i, a;
@@ -870,13 +923,23 @@
}
-static void pbkdf2(char *passwd, unsigned char *salt, unsigned char *ikey, void *params UNUSED) {
+static int pbkdf2(char *passwd, unsigned char *salt,
+ unsigned char *ikey, void *params UNUSED)
+{
/* Turn the password into a key and IV that can decrypt the master key */
- PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN,
+ unsigned int keysize;
+ char* master_key = (char*)convert_hex_ascii_to_key(passwd, &keysize);
+ if (!master_key) return -1;
+ PKCS5_PBKDF2_HMAC_SHA1(master_key, keysize, salt, SALT_LEN,
HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey);
+
+ free (master_key);
+ return 0;
}
-static void scrypt(char *passwd, unsigned char *salt, unsigned char *ikey, void *params) {
+static int scrypt(char *passwd, unsigned char *salt,
+ unsigned char *ikey, void *params)
+{
struct crypt_mnt_ftr *ftr = (struct crypt_mnt_ftr *) params;
int N = 1 << ftr->N_factor;
@@ -884,8 +947,14 @@
int p = 1 << ftr->p_factor;
/* Turn the password into a key and IV that can decrypt the master key */
- crypto_scrypt((unsigned char *) passwd, strlen(passwd), salt, SALT_LEN, N, r, p, ikey,
+ unsigned int keysize;
+ unsigned char* master_key = convert_hex_ascii_to_key(passwd, &keysize);
+ if (!master_key) return -1;
+ crypto_scrypt(master_key, keysize, salt, SALT_LEN, N, r, p, ikey,
KEY_LEN_BYTES + IV_LEN_BYTES);
+
+ free (master_key);
+ return 0;
}
static int encrypt_master_key(char *passwd, unsigned char *salt,
@@ -899,7 +968,10 @@
/* Turn the password into a key and IV that can decrypt the master key */
get_device_scrypt_params(crypt_ftr);
- scrypt(passwd, salt, ikey, crypt_ftr);
+ if (scrypt(passwd, salt, ikey, crypt_ftr)) {
+ SLOGE("scrypt failed");
+ return -1;
+ }
/* Initialize the decryption engine */
if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) {
@@ -937,7 +1009,10 @@
int decrypted_len, final_len;
/* Turn the password into a key and IV that can decrypt the master key */
- kdf(passwd, salt, ikey, kdf_params);
+ if (kdf(passwd, salt, ikey, kdf_params)) {
+ SLOGE("kdf failed");
+ return -1;
+ }
/* Initialize the decryption engine */
if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) {
@@ -1068,7 +1143,7 @@
}
}
-int cryptfs_restart(void)
+static int cryptfs_restart_internal(int restart_main)
{
char fs_type[32];
char real_blkdev[MAXPATHLEN];
@@ -1090,32 +1165,34 @@
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.
- */
+ if (restart_main) {
+ /* 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");
+ /* 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");
- /* Ugh, shutting down the framework is not synchronous, so until it
- * can be fixed, this horrible hack will wait a moment for it all to
- * shut down before proceeding. Without it, some devices cannot
- * restart the graphics services.
- */
- sleep(2);
+ /* Ugh, shutting down the framework is not synchronous, so until it
+ * can be fixed, this horrible hack will wait a moment for it all to
+ * shut down before proceeding. Without it, some devices cannot
+ * restart the graphics services.
+ */
+ sleep(2);
+ }
/* Now that the framework is shutdown, we should be able to umount()
* the tmpfs filesystem, and mount the real one.
@@ -1163,6 +1240,12 @@
return rc;
}
+int cryptfs_restart(void)
+{
+ /* Call internal implementation forcing a restart of main service group */
+ return cryptfs_restart_internal(1);
+}
+
static int do_crypto_complete(char *mount_point UNUSED)
{
struct crypt_mnt_ftr crypt_ftr;
@@ -1204,45 +1287,33 @@
return 0;
}
-static int test_mount_encrypted_fs(char *passwd, char *mount_point, char *label)
+static int test_mount_encrypted_fs(struct crypt_mnt_ftr* crypt_ftr,
+ 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 decrypted_master_key[32];
char crypto_blkdev[MAXPATHLEN];
char real_blkdev[MAXPATHLEN];
char tmp_mount_point[64];
unsigned int orig_failed_decrypt_count;
- char encrypted_state[PROPERTY_VALUE_MAX];
int rc;
kdf_func kdf;
void *kdf_params;
- property_get("ro.crypto.state", encrypted_state, "");
- if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) {
- SLOGE("encrypted fs already validated or not running with encryption, aborting");
- return -1;
- }
+ SLOGD("crypt_ftr->fs_size = %lld\n", crypt_ftr->fs_size);
+ orig_failed_decrypt_count = crypt_ftr->failed_decrypt_count;
- fs_mgr_get_crypt_info(fstab, 0, real_blkdev, sizeof(real_blkdev));
-
- if (get_crypt_ftr_and_key(&crypt_ftr)) {
- SLOGE("Error getting crypt footer and key\n");
- return -1;
- }
-
- SLOGD("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) ) {
- if (decrypt_master_key(passwd, decrypted_master_key, &crypt_ftr)) {
+ if (! (crypt_ftr->flags & CRYPT_MNT_KEY_UNENCRYPTED) ) {
+ if (decrypt_master_key(passwd, decrypted_master_key, crypt_ftr)) {
SLOGE("Failed to decrypt master key\n");
return -1;
}
}
- if (create_crypto_blk_dev(&crypt_ftr, decrypted_master_key,
- real_blkdev, crypto_blkdev, label)) {
+ fs_mgr_get_crypt_info(fstab, 0, real_blkdev, sizeof(real_blkdev));
+
+ if (create_crypto_blk_dev(crypt_ftr, decrypted_master_key,
+ real_blkdev, crypto_blkdev, label)) {
SLOGE("Error creating decrypted block device\n");
return -1;
}
@@ -1259,22 +1330,22 @@
if (fs_mgr_do_mount(fstab, DATA_MNT_POINT, crypto_blkdev, tmp_mount_point)) {
SLOGE("Error temp mounting decrypted block device\n");
delete_crypto_blk_dev(label);
- crypt_ftr.failed_decrypt_count++;
+ 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;
+ crypt_ftr->failed_decrypt_count = 0;
}
- if (orig_failed_decrypt_count != crypt_ftr.failed_decrypt_count) {
- put_crypt_ftr_and_key(&crypt_ftr);
+ if (orig_failed_decrypt_count != crypt_ftr->failed_decrypt_count) {
+ put_crypt_ftr_and_key(crypt_ftr);
}
- if (crypt_ftr.failed_decrypt_count) {
+ if (crypt_ftr->failed_decrypt_count) {
/* We failed to mount the device, so return an error */
- rc = crypt_ftr.failed_decrypt_count;
+ rc = crypt_ftr->failed_decrypt_count;
} else {
/* Woot! Success! Save the name of the crypto block device
@@ -1293,12 +1364,12 @@
/*
* Upgrade if we're not using the latest KDF.
*/
- if (crypt_ftr.kdf_type != KDF_SCRYPT) {
- crypt_ftr.kdf_type = KDF_SCRYPT;
- rc = encrypt_master_key(passwd, crypt_ftr.salt, saved_master_key, crypt_ftr.master_key,
- &crypt_ftr);
+ if (crypt_ftr->kdf_type != KDF_SCRYPT) {
+ crypt_ftr->kdf_type = KDF_SCRYPT;
+ rc = encrypt_master_key(passwd, crypt_ftr->salt, saved_master_key,
+ crypt_ftr->master_key, crypt_ftr);
if (!rc) {
- rc = put_crypt_ftr_and_key(&crypt_ftr);
+ rc = put_crypt_ftr_and_key(crypt_ftr);
}
SLOGD("Key Derivation Function upgrade: rc=%d\n", rc);
}
@@ -1362,12 +1433,35 @@
return do_crypto_complete("/data");
}
+int check_unmounted_and_get_ftr(struct crypt_mnt_ftr* crypt_ftr)
+{
+ char encrypted_state[PROPERTY_VALUE_MAX];
+ property_get("ro.crypto.state", encrypted_state, "");
+ if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) {
+ SLOGE("encrypted fs already validated or not running with encryption,"
+ " aborting");
+ return -1;
+ }
+
+ if (get_crypt_ftr_and_key(crypt_ftr)) {
+ SLOGE("Error getting crypt footer and key");
+ return -1;
+ }
+
+ return 0;
+}
+
int cryptfs_check_passwd(char *passwd)
{
- int rc = -1;
+ struct crypt_mnt_ftr crypt_ftr;
+ int rc;
- rc = test_mount_encrypted_fs(passwd, DATA_MNT_POINT, "userdata");
+ rc = check_unmounted_and_get_ftr(&crypt_ftr);
+ if (rc)
+ return rc;
+ rc = test_mount_encrypted_fs(&crypt_ftr, passwd,
+ DATA_MNT_POINT, "userdata");
return rc;
}
@@ -1987,6 +2081,11 @@
crypt_ftr.fs_size = nr_sec;
}
crypt_ftr.flags |= CRYPT_ENCRYPTION_IN_PROGRESS;
+
+ /** @TODO If we keep this route, must pass in crypt_type.
+ * If all devices are encrypted by default, we don't need that change.
+ */
+ crypt_ftr.crypt_type = CRYPT_TYPE_PASSWORD;
strcpy((char *)crypt_ftr.crypto_type_name, "aes-cbc-essiv:sha256");
/* Make an encrypted master key */
@@ -2143,24 +2242,36 @@
return -1;
}
-int cryptfs_changepw(char *newpw)
+int cryptfs_changepw(int crypt_type, char *newpw)
{
struct crypt_mnt_ftr crypt_ftr;
unsigned char decrypted_master_key[KEY_LEN_BYTES];
/* This is only allowed after we've successfully decrypted the master key */
- if (! master_key_saved) {
+ if (!master_key_saved) {
SLOGE("Key not saved, aborting");
return -1;
}
+ if (crypt_type < 0 || crypt_type > CRYPT_TYPE_MAX_TYPE) {
+ SLOGE("Invalid crypt_type %d", crypt_type);
+ return -1;
+ }
+
/* get key */
if (get_crypt_ftr_and_key(&crypt_ftr)) {
- SLOGE("Error getting crypt footer and key");
- return -1;
+ SLOGE("Error getting crypt footer and key");
+ return -1;
}
- encrypt_master_key(newpw, crypt_ftr.salt, saved_master_key, crypt_ftr.master_key, &crypt_ftr);
+ crypt_ftr.crypt_type = crypt_type;
+
+ encrypt_master_key(crypt_type == CRYPT_TYPE_DEFAULT ? DEFAULT_PASSWORD
+ : newpw,
+ crypt_ftr.salt,
+ saved_master_key,
+ crypt_ftr.master_key,
+ &crypt_ftr);
/* save the key */
put_crypt_ftr_and_key(&crypt_ftr);
@@ -2307,3 +2418,52 @@
out:
return rc;
}
+
+/* Checks userdata. Attempt to mount the volume if default-
+ * encrypted.
+ * On success trigger next init phase and return 0.
+ * Currently do not handle failure - see TODO below.
+ */
+int cryptfs_mount_default_encrypted(void)
+{
+ char decrypt_state[PROPERTY_VALUE_MAX];
+ property_get("vold.decrypt", decrypt_state, "0");
+ if (!strcmp(decrypt_state, "0")) {
+ SLOGE("Not encrypted - should not call here");
+ } else {
+ int crypt_type = cryptfs_get_password_type();
+ if (crypt_type < 0 || crypt_type > CRYPT_TYPE_MAX_TYPE) {
+ SLOGE("Bad crypt type - error");
+ } else if (crypt_type != CRYPT_TYPE_DEFAULT) {
+ SLOGD("Password is not default - "
+ "starting min framework to prompt");
+ property_set("vold.decrypt", "trigger_restart_min_framework");
+ return 0;
+ } else if (cryptfs_check_passwd(DEFAULT_PASSWORD) == 0) {
+ SLOGD("Password is default - restarting filesystem");
+ cryptfs_restart_internal(0);
+ return 0;
+ } else {
+ SLOGE("Encrypted, default crypt type but can't decrypt");
+ }
+ }
+
+ /** @TODO make sure we factory wipe in this situation
+ * In general if we got here there is no recovery
+ */
+ return 0;
+}
+
+/* Returns type of the password, default, pattern, pin or password.
+ */
+int cryptfs_get_password_type(void)
+{
+ struct crypt_mnt_ftr crypt_ftr;
+
+ if (get_crypt_ftr_and_key(&crypt_ftr)) {
+ SLOGE("Error getting crypt footer and key\n");
+ return -1;
+ }
+
+ return crypt_ftr.crypt_type;
+}