decrypt: AOSP 10 requires the use of fscrypt

fscrypt aosp doc: https://source.android.com/security/encryption/file-based
kernel fscrypt doc: https://www.kernel.org/doc/html/v4.18/filesystems/fscrypt.html

This commit implements the ability for TWRP to use fscrypt to decrypt
files on the fscrypt implementation. It has been implemented mostly
in a new successor library to e4crypt called libtwrpfscrypt. Most of the
code was ported from AOSP vold.

Notable updates include:
 - updated policy storage by libtar
 - lookup of fbe policies by libtwrpfscrypt
 - threaded keystore operations

Big thanks to Dees_Troy for the initial trailblazing
of encryption in TWRP.

Change-Id: I69cd2eba3693a9914e00213d4943229635d0cdae
diff --git a/crypto/fscrypt/HashPassword.h b/crypto/fscrypt/HashPassword.h
new file mode 100644
index 0000000..73880b1
--- /dev/null
+++ b/crypto/fscrypt/HashPassword.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2016 Team Win Recovery 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.
+ */
+
+#ifndef __HASH_PASSWORD_H
+#define __HASH_PASSWORD_H
+
+#include <string>
+
+#define FBE_PERSONALIZATION "Android FBE credential hash"
+#define PERSONALISATION_WEAVER_KEY "weaver-key"
+#define PERSONALISATION_WEAVER_PASSWORD "weaver-pwd"
+#define PERSONALISATION_APPLICATION_ID "application-id"
+#define PERSONALIZATION_FBE_KEY "fbe-key"
+#define PERSONALIZATION_USER_GK_AUTH "user-gk-authentication"
+#define PERSONALISATION_SECDISCARDABLE "secdiscardable-transform"
+#define PERSONALISATION_CONTEXT "android-synthetic-password-personalization-context"
+
+void* PersonalizedHashBinary(const char* prefix, const char* key, const size_t key_size);
+
+std::string PersonalizedHash(const char* prefix, const char* key, const size_t key_size);
+std::string PersonalizedHash(const char* prefix, const std::string& Password);
+std::string PersonalizedHashSP800(const char* label, const char* context, const char* key, const size_t key_size);
+std::string HashPassword(const std::string& Password);
+
+template <class T>
+void endianswap(T *objp) {
+	unsigned char *memp = reinterpret_cast<unsigned char*>(objp);
+	std::reverse(memp, memp + sizeof(T));
+}
+
+#endif