Initial import of Widevine Common Encryption DRM engine

Builds libwvmdrmengine.so, which is loaded by the new
MediaDrm APIs to support playback of Widevine/CENC
protected content.

Change-Id: I6f57dd37083dfd96c402cb9dd137c7d74edc8f1c

libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp

@@ -0,0 +1,106 @@
+//
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "WVCdm"
+#include <utils/Log.h>
+
+#include "WVCryptoPlugin.h"
+
+#include <string>
+#include <vector>
+
+#include "utils/Errors.h"
+#include "wv_cdm_constants.h"
+
+namespace wvdrm {
+
+using namespace android;
+using namespace std;
+using namespace wvcdm;
+
+WVCryptoPlugin::WVCryptoPlugin(const void* data, size_t size,
+                               WvContentDecryptionModule* cdm)
+    : mCDM(cdm),
+      mSessionId(static_cast<const char*>(data), size) {}
+
+bool WVCryptoPlugin::requiresSecureDecoderComponent(const char *mime) const {
+  // TODO: Determine if we are using L1 or L3 and return an appropriate value.
+  //       For Demo 2, we are always L3.
+  return false;
+}
+
+// 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 should never happen
+// for AES-CTR.
+ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
+                                const uint8_t iv[KEY_IV_SIZE], Mode mode,
+                                const void* srcPtr, const SubSample* subSamples,
+                                size_t numSubSamples, void* dstPtr,
+                                AString *errorDetailMsg) {
+  if (mode != kMode_Unencrypted && mode != kMode_AES_CTR) {
+    return BAD_TYPE;
+  }
+
+  if (secure) {
+    // TODO: Can't do secure in the Demo 2 milestone
+    return -EPERM;
+  }
+
+  // Convert parameters to the form the CDM wishes to consume them in.
+  const KeyId keyId(reinterpret_cast<const char*>(key), KEY_ID_SIZE);
+  const vector<uint8_t> ivVector(iv, iv + KEY_IV_SIZE);
+  const uint8_t* const source = static_cast<const uint8_t*>(srcPtr);
+  uint8_t* const dest = static_cast<uint8_t*>(dstPtr);
+
+  // Iterate through subsamples, sending them to the CDM serially.
+  size_t offset = 0;
+
+  for (size_t i = 0; i < numSubSamples; ++i) {
+    const SubSample &subSample = subSamples[i];
+
+    if (mode == kMode_Unencrypted && subSample.mNumBytesOfEncryptedData != 0) {
+      return -EINVAL;
+    }
+
+    // "Decrypt" any unencrypted data.  Per the ISO-CENC standard, clear data
+    // comes before encrypted data.
+    if (subSample.mNumBytesOfClearData != 0) {
+      CdmResponseType res = mCDM->Decrypt(mSessionId, false, keyId,
+                                          source + offset,
+                                          subSample.mNumBytesOfClearData,
+                                          ivVector, offset % 16, dest + offset);
+
+      if (res != wvcdm::NO_ERROR) {
+        ALOGE("Decrypt error result in session %s during unencrypted block: %d",
+              mSessionId.c_str(), res);
+        return -EINVAL;
+      }
+
+      offset += subSample.mNumBytesOfClearData;
+    }
+
+    // Decrypt any encrypted data.  Per the ISO-CENC standard, encrypted data
+    // comes after clear data.
+    if (subSample.mNumBytesOfEncryptedData != 0) {
+      CdmResponseType res = mCDM->Decrypt(mSessionId, true, keyId,
+                                          source + offset,
+                                          subSample.mNumBytesOfEncryptedData,
+                                          ivVector, offset % 16, dest + offset);
+
+      if (res != wvcdm::NO_ERROR) {
+        ALOGE("Decrypt error result in session %s during encrypted block: %d",
+              mSessionId.c_str(), res);
+        return -EINVAL;
+      }
+
+      offset += subSample.mNumBytesOfEncryptedData;
+    }
+  }
+
+  return static_cast<ssize_t>(offset);
+}
+
+}  // namespace wvdrm