Securely encrypt the master key
Move all key management into vold
Reuse vold's existing key management through the crypto footer
to manage the device wide keys.
Use ro.crypto.type flag to determine crypto type, which prevents
any issues when running in block encrypted mode, as well as speeding
up boot in block or no encryption.
This is one of four changes to enable this functionality:
https://android-review.googlesource.com/#/c/148586/
https://android-review.googlesource.com/#/c/148604/
https://android-review.googlesource.com/#/c/148606/
https://android-review.googlesource.com/#/c/148607/
Bug: 18151196
Change-Id: I3c68691717a61b5e1df76423ca0c02baff0dab98
diff --git a/cryptfs.c b/cryptfs.c
index 91487ed..95b882f 100644
--- a/cryptfs.c
+++ b/cryptfs.c
@@ -53,7 +53,8 @@
#include "VolumeManager.h"
#include "VoldUtil.h"
#include "crypto_scrypt.h"
-#include "ext4_crypt.h"
+#include "Ext4Crypt.h"
+#include "ext4_crypt_init_extensions.h"
#include "ext4_utils.h"
#include "f2fs_sparseblock.h"
#include "CheckBattery.h"
@@ -1310,7 +1311,7 @@
/* Encrypt the master key */
if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len,
- decrypted_master_key, KEY_LEN_BYTES)) {
+ decrypted_master_key, KEY_LEN_BYTES)) {
SLOGE("EVP_EncryptUpdate failed\n");
return -1;
}
@@ -1345,7 +1346,7 @@
return 0;
}
-static int decrypt_master_key_aux(char *passwd, unsigned char *salt,
+static int decrypt_master_key_aux(const char *passwd, unsigned char *salt,
unsigned char *encrypted_master_key,
unsigned char *decrypted_master_key,
kdf_func kdf, void *kdf_params,
@@ -1410,7 +1411,7 @@
}
}
-static int decrypt_master_key(char *passwd, unsigned char *decrypted_master_key,
+static int decrypt_master_key(const char *passwd, unsigned char *decrypted_master_key,
struct crypt_mnt_ftr *crypt_ftr,
unsigned char** intermediate_key,
size_t* intermediate_key_size)
@@ -3804,3 +3805,46 @@
password_expiry_time = 0;
}
}
+
+int cryptfs_enable_file()
+{
+ return e4crypt_enable(DATA_MNT_POINT);
+}
+
+int cryptfs_create_default_ftr(struct crypt_mnt_ftr* crypt_ftr, __attribute__((unused))int key_length)
+{
+ if (cryptfs_init_crypt_mnt_ftr(crypt_ftr)) {
+ SLOGE("Failed to initialize crypt_ftr");
+ return -1;
+ }
+
+ if (create_encrypted_random_key(DEFAULT_PASSWORD, crypt_ftr->master_key,
+ crypt_ftr->salt, crypt_ftr)) {
+ SLOGE("Cannot create encrypted master key\n");
+ return -1;
+ }
+
+ //crypt_ftr->keysize = key_length / 8;
+ return 0;
+}
+
+int cryptfs_get_master_key(struct crypt_mnt_ftr* ftr, const char* password,
+ unsigned char* master_key)
+{
+ int rc;
+
+ // ext4enc:TODO check intermediate_key to see if this is valid key
+ unsigned char* intermediate_key = 0;
+ size_t intermediate_key_size = 0;
+ rc = decrypt_master_key(password, master_key, ftr, &intermediate_key,
+ &intermediate_key_size);
+
+ return rc;
+}
+
+int cryptfs_set_password(struct crypt_mnt_ftr* ftr, const char* password,
+ const unsigned char* master_key)
+{
+ return encrypt_master_key(password, ftr->salt, master_key, ftr->master_key,
+ ftr);
+}