Implement OpenSSL-Based Decryptor

Implements an object that does AES-CTR-128 by invoking OpenSSL.

Change-Id: I8457899ec8b69bd8f0d727029985c9580911cf99

4 files changed, 126 insertions, 1 deletions

diff --git a/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.cpp b/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.cpp
new file mode 100644
index 0000000..01f8d65
--- /dev/null
+++ b/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.cpp
@@ -0,0 +1,67 @@
+/*
+ * 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 <openssl/aes.h>
+
+#include "AesCtrDecryptor.h"
+
+namespace clearkeydrm {
+
+static const size_t kBlockBitCount = kBlockSize * 8;
+
+android::status_t AesCtrDecryptor::decrypt(const android::Vector<uint8_t>& key,
+        const Iv iv, const uint8_t* source,
+        uint8_t* destination,
+        const SubSample* subSamples,
+        size_t numSubSamples,
+        size_t* bytesDecryptedOut) {
+    uint32_t blockOffset = 0;
+    uint8_t previousEncryptedCounter[kBlockSize];
+    memset(previousEncryptedCounter, 0, kBlockSize);
+
+    size_t offset = 0;
+    AES_KEY opensslKey;
+    AES_set_encrypt_key(key.array(), kBlockBitCount, &opensslKey);
+    Iv opensslIv;
+    memcpy(opensslIv, iv, sizeof(opensslIv));
+
+    for (size_t i = 0; i < numSubSamples; ++i) {
+        const SubSample& subSample = subSamples[i];
+
+        if (subSample.mNumBytesOfClearData > 0) {
+            memcpy(destination + offset, source + offset,
+                    subSample.mNumBytesOfClearData);
+            offset += subSample.mNumBytesOfClearData;
+        }
+
+        if (subSample.mNumBytesOfEncryptedData > 0) {
+            AES_ctr128_encrypt(source + offset, destination + offset,
+                    subSample.mNumBytesOfEncryptedData, &opensslKey,
+                    opensslIv, previousEncryptedCounter,
+                    &blockOffset);
+            offset += subSample.mNumBytesOfEncryptedData;
+        }
+    }
+
+    *bytesDecryptedOut = offset;
+    return android::OK;
+}
+
+} // namespace clearkeydrm
diff --git a/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.h b/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.h
new file mode 100644
index 0000000..b416266
--- /dev/null
+++ b/drm/mediadrm/plugins/clearkey/AesCtrDecryptor.h
@@ -0,0 +1,44 @@
+/*
+ * 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.
+ */
+
+#ifndef CLEARKEY_AES_CTR_DECRYPTOR_H_
+#define CLEARKEY_AES_CTR_DECRYPTOR_H_
+
+#include <media/stagefright/foundation/ABase.h>
+#include <Utils.h>
+#include <utils/Errors.h>
+#include <utils/Vector.h>
+
+#include "ClearKeyTypes.h"
+
+namespace clearkeydrm {
+
+class AesCtrDecryptor {
+public:
+    AesCtrDecryptor() {}
+
+    android::status_t decrypt(const android::Vector<uint8_t>& key, const Iv iv,
+            const uint8_t* source, uint8_t* destination,
+            const SubSample* subSamples, size_t numSubSamples,
+            size_t* bytesDecryptedOut);
+
+private:
+    DISALLOW_EVIL_CONSTRUCTORS(AesCtrDecryptor);
+};
+
+} // namespace clearkeydrm
+
+#endif // CLEARKEY_AES_CTR_DECRYPTOR_H_
diff --git a/drm/mediadrm/plugins/clearkey/Android.mk b/drm/mediadrm/plugins/clearkey/Android.mk
index 22613cc..59e992b 100644
--- a/drm/mediadrm/plugins/clearkey/Android.mk
+++ b/drm/mediadrm/plugins/clearkey/Android.mk
@@ -17,10 +17,14 @@ LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := \
+    AesCtrDecryptor.cpp \
+    JsonWebKey.cpp \
     Utils.cpp \
 
 LOCAL_C_INCLUDES := \
     bionic \
+    external/jsmn \
+    external/openssl/include \
     frameworks/av/drm/mediadrm/plugins/clearkey \
     frameworks/av/include \
     frameworks/native/include \
@@ -30,10 +34,19 @@ LOCAL_MODULE := libdrmclearkeyplugin
 LOCAL_MODULE_PATH := $(TARGET_OUT_VENDOR_SHARED_LIBRARIES)/mediadrm
 
 LOCAL_SHARED_LIBRARIES := \
+    libcrypto \
     liblog \
     libstagefright_foundation \
     libutils \
 
+LOCAL_STATIC_LIBRARIES := \
+    libjsmn \
+
 LOCAL_MODULE_TAGS := optional
 
 include $(BUILD_SHARED_LIBRARY)
+
+#########################################################################
+# Build unit tests
+
+include $(LOCAL_PATH)/tests/Android.mk
diff --git a/drm/mediadrm/plugins/clearkey/ClearKeyTypes.h b/drm/mediadrm/plugins/clearkey/ClearKeyTypes.h
index 65b434f..a28959a 100644
--- a/drm/mediadrm/plugins/clearkey/ClearKeyTypes.h
+++ b/drm/mediadrm/plugins/clearkey/ClearKeyTypes.h
@@ -18,12 +18,13 @@
 #define CLEARKEY_TYPES_H_
 
 #include <media/hardware/CryptoAPI.h>
+#include <openssl/aes.h>
 #include <utils/KeyedVector.h>
 #include <utils/Vector.h>
 
 namespace clearkeydrm {
 
-const uint8_t kBlockSize = 16;
+const uint8_t kBlockSize = AES_BLOCK_SIZE;
 typedef uint8_t KeyId[kBlockSize];
 typedef uint8_t Iv[kBlockSize];