1 files changed, 83 insertions, 0 deletions
diff --git a/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp b/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp
new file mode 100644
index 0000000..adad136
--- /dev/null
+++ b/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "ClearKeyCryptoPlugin"
+#include <utils/Log.h>
+
+#include <media/stagefright/MediaErrors.h>
+#include <utils/Errors.h>
+
+#include "CryptoPlugin.h"
+
+namespace clearkeydrm {
+
+using android::Vector;
+using android::AString;
+using android::status_t;
+
+// Returns negative values for error code and positive values for the size of
+// decrypted data.  In theory, the output size can be larger than the input
+// size, but in practice this will never happen for AES-CTR.
+ssize_t CryptoPlugin::decrypt(bool secure, const KeyId keyId, const Iv iv,
+                              Mode mode, const void* srcPtr,
+                              const SubSample* subSamples, size_t numSubSamples,
+                              void* dstPtr, AString* errorDetailMsg) {
+    if (secure) {
+        errorDetailMsg->setTo("Secure decryption is not supported with "
+                              "ClearKey.");
+        return android::ERROR_DRM_CANNOT_HANDLE;
+    }
+
+    if (mode == kMode_Unencrypted) {
+        size_t offset = 0;
+        for (size_t i = 0; i < numSubSamples; ++i) {
+            const SubSample& subSample = subSamples[i];
+
+            if (subSample.mNumBytesOfEncryptedData != 0) {
+                errorDetailMsg->setTo(
+                        "Encrypted subsamples found in allegedly unencrypted "
+                        "data.");
+                return android::ERROR_DRM_DECRYPT;
+            }
+
+            if (subSample.mNumBytesOfClearData != 0) {
+                memcpy(reinterpret_cast<uint8_t*>(dstPtr) + offset,
+                       reinterpret_cast<const uint8_t*>(srcPtr) + offset,
+                       subSample.mNumBytesOfClearData);
+                offset += subSample.mNumBytesOfClearData;
+            }
+        }
+        return static_cast<ssize_t>(offset);
+    } else if (mode == kMode_AES_CTR) {
+        size_t bytesDecrypted;
+        status_t res = mSession->decrypt(keyId, iv, srcPtr, dstPtr, subSamples,
+                                         numSubSamples, &bytesDecrypted);
+        if (res == android::OK) {
+            return static_cast<ssize_t>(bytesDecrypted);
+        } else {
+            errorDetailMsg->setTo("Decryption Error");
+            return static_cast<ssize_t>(res);
+        }
+    } else {
+        errorDetailMsg->setTo(
+                "Selected encryption mode is not supported by the ClearKey DRM "
+                "Plugin.");
+        return android::ERROR_DRM_CANNOT_HANDLE;
+    }
+}
+
+}  // namespace clearkeydrm