From bd7492de28963b7e74e8e5d3f17ec9a5a287d9c3 Mon Sep 17 00:00:00 2001
From: Ethan Yonker <dees_troy@teamw.in>
Date: Wed, 7 Dec 2016 13:55:01 -0600
Subject: Support File Based Encryption

Change-Id: Ib688ddd0c32d3999590cacd86b6d9b18eac336e9
---
 crypto/ext4crypt/Keymaster.h | 110 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 crypto/ext4crypt/Keymaster.h

(limited to 'crypto/ext4crypt/Keymaster.h')

diff --git a/crypto/ext4crypt/Keymaster.h b/crypto/ext4crypt/Keymaster.h
new file mode 100644
index 000000000..11b3532ad
--- /dev/null
+++ b/crypto/ext4crypt/Keymaster.h
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_VOLD_KEYMASTER_H
+#define ANDROID_VOLD_KEYMASTER_H
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include <keymaster/authorization_set.h>
+
+namespace android {
+namespace vold {
+
+using namespace keymaster;
+
+// C++ wrappers to the Keymaster C interface.
+// This is tailored to the needs of KeyStorage, but could be extended to be
+// a more general interface.
+
+// Class that wraps a keymaster1_device_t or keymaster2_device_t and provides methods
+// they have in common. Also closes the device on destruction.
+class IKeymasterDevice;
+
+// Wrapper for a keymaster_operation_handle_t representing an
+// ongoing Keymaster operation.  Aborts the operation
+// in the destructor if it is unfinished. Methods log failures
+// to LOG(ERROR).
+class KeymasterOperation {
+  public:
+    ~KeymasterOperation();
+    // Is this instance valid? This is false if creation fails, and becomes
+    // false on finish or if an update fails.
+    explicit operator bool() { return mDevice != nullptr; }
+    // Call "update" repeatedly until all of the input is consumed, and
+    // concatenate the output. Return true on success.
+    bool updateCompletely(const std::string& input, std::string* output);
+    // Finish; pass nullptr for the "output" param.
+    bool finish();
+    // Finish and write the output to this string.
+    bool finishWithOutput(std::string* output);
+    // Move constructor
+    KeymasterOperation(KeymasterOperation&& rhs) {
+        mOpHandle = std::move(rhs.mOpHandle);
+        mDevice = std::move(rhs.mDevice);
+    }
+
+  private:
+    KeymasterOperation(std::shared_ptr<IKeymasterDevice> d, keymaster_operation_handle_t h)
+        : mDevice{d}, mOpHandle{h} {}
+    std::shared_ptr<IKeymasterDevice> mDevice;
+    keymaster_operation_handle_t mOpHandle;
+    DISALLOW_COPY_AND_ASSIGN(KeymasterOperation);
+    friend class Keymaster;
+};
+
+// Wrapper for a Keymaster device for methods that start a KeymasterOperation or are not
+// part of one.
+class Keymaster {
+  public:
+    Keymaster();
+    // false if we failed to open the keymaster device.
+    explicit operator bool() { return mDevice != nullptr; }
+    // Generate a key in the keymaster from the given params.
+    //bool generateKey(const AuthorizationSet& inParams, std::string* key);
+    // If the keymaster supports it, permanently delete a key.
+    bool deleteKey(const std::string& key);
+    // Begin a new cryptographic operation, collecting output parameters.
+    KeymasterOperation begin(keymaster_purpose_t purpose, const std::string& key,
+                             const AuthorizationSet& inParams, AuthorizationSet* outParams);
+    // Begin a new cryptographic operation; don't collect output parameters.
+    KeymasterOperation begin(keymaster_purpose_t purpose, const std::string& key,
+                             const AuthorizationSet& inParams);
+
+  private:
+    std::shared_ptr<IKeymasterDevice> mDevice;
+    DISALLOW_COPY_AND_ASSIGN(Keymaster);
+};
+
+template <keymaster_tag_t Tag>
+inline AuthorizationSetBuilder& addStringParam(AuthorizationSetBuilder&& params,
+                                               TypedTag<KM_BYTES, Tag> tag,
+                                               const std::string& val) {
+    return params.Authorization(tag, val.data(), val.size());
+}
+
+template <keymaster_tag_t Tag>
+inline void addStringParam(AuthorizationSetBuilder* params, TypedTag<KM_BYTES, Tag> tag,
+                           const std::string& val) {
+    params->Authorization(tag, val.data(), val.size());
+}
+
+}  // namespace vold
+}  // namespace android
+
+#endif
-- 
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