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/*
* Copyright (C) 2013 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.
*/
package android.media;
import android.media.MediaDrmException;
import java.lang.ref.WeakReference;
import java.util.UUID;
import java.util.HashMap;
import java.util.List;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.Bundle;
import android.os.Parcel;
import android.util.Log;
/**
* MediaDrm can be used to obtain keys for decrypting protected media streams, in
* conjunction with {@link android.media.MediaCrypto}. The MediaDrm APIs
* are designed to support the ISO/IEC 23001-7: Common Encryption standard, but
* may also be used to implement other encryption schemes.
*
* Encrypted content is prepared using an encryption server and stored in a content
* library. The encrypted content is streamed or downloaded from the content library to
* client devices via content servers. Licenses to view the content are obtained from
* a License Server.
*
*
*
* Keys are requested from the license server using a key request. The key
* response is delivered to the client app, which provides the response to the
* MediaDrm API.
*
* A Provisioning server may be required to distribute device-unique credentials to
* the devices.
*
* Enforcing requirements related to the number of devices that may play content
* simultaneously can be performed either through key renewal or using the secure
* stop methods.
*
* The following sequence diagram shows the interactions between the objects
* involved while playing back encrypted content:
*
*
*
* The app first constructs {@link android.media.MediaExtractor} and
* {@link android.media.MediaCodec} objects. It accesses the DRM-scheme-identifying UUID,
* typically from metadata in the content, and uses this UUID to construct an instance
* of a MediaDrm object that is able to support the DRM scheme required by the content.
* Crypto schemes are assigned 16 byte UUIDs. The method {@link #isCryptoSchemeSupported}
* can be used to query if a given scheme is supported on the device.
*
* The app calls {@link #openSession} to generate a sessionId that will uniquely identify
* the session in subsequent interactions. The app next uses the MediaDrm object to
* obtain a key request message and send it to the license server, then provide
* the server's response to the MediaDrm object.
*
* Once the app has a sessionId, it can construct a MediaCrypto object from the UUID and
* sessionId. The MediaCrypto object is registered with the MediaCodec in the
* {@link MediaCodec.#configure} method to enable the codec to decrypt content.
*
* When the app has constructed {@link android.media.MediaExtractor},
* {@link android.media.MediaCodec} and {@link android.media.MediaCrypto} objects,
* it proceeds to pull samples from the extractor and queue them into the decoder. For
* encrypted content, the samples returned from the extractor remain encrypted, they
* are only decrypted when the samples are delivered to the decoder.
*
Callbacks
* Applications should register for informational events in order
* to be informed of key state updates during playback or streaming.
* Registration for these events is done via a call to
* {@link #setOnEventListener}. In order to receive the respective
* callback associated with this listener, applications are required to create
* MediaDrm objects on a thread with its own Looper running (main UI
* thread by default has a Looper running).
*/
public final class MediaDrm {
private final static String TAG = "MediaDrm";
private EventHandler mEventHandler;
private OnEventListener mOnEventListener;
private int mNativeContext;
/**
* Query if the given scheme identified by its UUID is supported on
* this device.
* @param uuid The UUID of the crypto scheme.
*/
public static final boolean isCryptoSchemeSupported(UUID uuid) {
return isCryptoSchemeSupportedNative(getByteArrayFromUUID(uuid), null);
}
/**
* Query if the given scheme identified by its UUID is supported on
* this device, and whether the drm plugin is able to handle the
* media container format specified by mimeType.
* @param uuid The UUID of the crypto scheme.
* @param mimeType The MIME type of the media container, e.g. "video/mp4"
* or "video/webm"
*/
public static final boolean isCryptoSchemeSupported(UUID uuid, String mimeType) {
return isCryptoSchemeSupportedNative(getByteArrayFromUUID(uuid), mimeType);
}
private static final byte[] getByteArrayFromUUID(UUID uuid) {
long msb = uuid.getMostSignificantBits();
long lsb = uuid.getLeastSignificantBits();
byte[] uuidBytes = new byte[16];
for (int i = 0; i < 8; ++i) {
uuidBytes[i] = (byte)(msb >>> (8 * (7 - i)));
uuidBytes[8 + i] = (byte)(lsb >>> (8 * (7 - i)));
}
return uuidBytes;
}
private static final native boolean isCryptoSchemeSupportedNative(byte[] uuid,
String mimeType);
/**
* Instantiate a MediaDrm object
*
* @param uuid The UUID of the crypto scheme.
*
* @throws UnsupportedSchemeException if the device does not support the
* specified scheme UUID
*/
public MediaDrm(UUID uuid) throws UnsupportedSchemeException {
Looper looper;
if ((looper = Looper.myLooper()) != null) {
mEventHandler = new EventHandler(this, looper);
} else if ((looper = Looper.getMainLooper()) != null) {
mEventHandler = new EventHandler(this, looper);
} else {
mEventHandler = null;
}
/* Native setup requires a weak reference to our object.
* It's easier to create it here than in C++.
*/
native_setup(new WeakReference(this),
getByteArrayFromUUID(uuid));
}
/**
* Register a callback to be invoked when an event occurs
*
* @param listener the callback that will be run
*/
public void setOnEventListener(OnEventListener listener)
{
mOnEventListener = listener;
}
/**
* Interface definition for a callback to be invoked when a drm event
* occurs
*/
public interface OnEventListener
{
/**
* Called when an event occurs that requires the app to be notified
*
* @param md the MediaDrm object on which the event occurred
* @param sessionId the DRM session ID on which the event occurred
* @param event indicates the event type
* @param extra an secondary error code
* @param data optional byte array of data that may be associated with the event
*/
void onEvent(MediaDrm md, byte[] sessionId, int event, int extra, byte[] data);
}
/**
* This event type indicates that the app needs to request a certificate from
* the provisioning server. The request message data is obtained using
* {@link #getProvisionRequest}
*/
public static final int EVENT_PROVISION_REQUIRED = 1;
/**
* This event type indicates that the app needs to request keys from a license
* server. The request message data is obtained using {@link #getKeyRequest}.
*/
public static final int EVENT_KEY_REQUIRED = 2;
/**
* This event type indicates that the licensed usage duration for keys in a session
* has expired. The keys are no longer valid.
*/
public static final int EVENT_KEY_EXPIRED = 3;
/**
* This event may indicate some specific vendor-defined condition, see your
* DRM provider documentation for details
*/
public static final int EVENT_VENDOR_DEFINED = 4;
private static final int DRM_EVENT = 200;
private class EventHandler extends Handler
{
private MediaDrm mMediaDrm;
public EventHandler(MediaDrm md, Looper looper) {
super(looper);
mMediaDrm = md;
}
@Override
public void handleMessage(Message msg) {
if (mMediaDrm.mNativeContext == 0) {
Log.w(TAG, "MediaDrm went away with unhandled events");
return;
}
switch(msg.what) {
case DRM_EVENT:
Log.i(TAG, "Drm event (" + msg.arg1 + "," + msg.arg2 + ")");
if (mOnEventListener != null) {
if (msg.obj != null && msg.obj instanceof Parcel) {
Parcel parcel = (Parcel)msg.obj;
byte[] sessionId = parcel.createByteArray();
if (sessionId.length == 0) {
sessionId = null;
}
byte[] data = parcel.createByteArray();
if (data.length == 0) {
data = null;
}
mOnEventListener.onEvent(mMediaDrm, sessionId, msg.arg1, msg.arg2, data);
}
}
return;
default:
Log.e(TAG, "Unknown message type " + msg.what);
return;
}
}
}
/*
* This method is called from native code when an event occurs. This method
* just uses the EventHandler system to post the event back to the main app thread.
* We use a weak reference to the original MediaPlayer object so that the native
* code is safe from the object disappearing from underneath it. (This is
* the cookie passed to native_setup().)
*/
private static void postEventFromNative(Object mediadrm_ref,
int eventType, int extra, Object obj)
{
MediaDrm md = (MediaDrm)((WeakReference)mediadrm_ref).get();
if (md == null) {
return;
}
if (md.mEventHandler != null) {
Message m = md.mEventHandler.obtainMessage(DRM_EVENT, eventType, extra, obj);
md.mEventHandler.sendMessage(m);
}
}
/**
* Open a new session with the MediaDrm object. A session ID is returned.
*
* @throws NotProvisionedException if provisioning is needed
* @throws ResourceBusyException if required resources are in use
*/
public native byte[] openSession() throws NotProvisionedException;
/**
* Close a session on the MediaDrm object that was previously opened
* with {@link #openSession}.
*/
public native void closeSession(byte[] sessionId);
/**
* This key request type species that the keys will be for online use, they will
* not be saved to the device for subsequent use when the device is not connected
* to a network.
*/
public static final int KEY_TYPE_STREAMING = 1;
/**
* This key request type specifies that the keys will be for offline use, they
* will be saved to the device for use when the device is not connected to a network.
*/
public static final int KEY_TYPE_OFFLINE = 2;
/**
* This key request type specifies that previously saved offline keys should be released.
*/
public static final int KEY_TYPE_RELEASE = 3;
/**
* Contains the opaque data an app uses to request keys from a license server
*/
public final static class KeyRequest {
KeyRequest() {}
/**
* Get the opaque message data
*/
public byte[] getData() { return mData; }
/**
* Get the default URL to use when sending the key request message to a
* server, if known. The app may prefer to use a different license
* server URL from other sources.
*/
public String getDefaultUrl() { return mDefaultUrl; }
private byte[] mData;
private String mDefaultUrl;
};
/**
* A key request/response exchange occurs between the app and a license server
* to obtain or release keys used to decrypt encrypted content.
*
* getKeyRequest() is used to obtain an opaque key request byte array that is
* delivered to the license server. The opaque key request byte array is returned
* in KeyRequest.data. The recommended URL to deliver the key request to is
* returned in KeyRequest.defaultUrl.
*
* After the app has received the key request response from the server,
* it should deliver to the response to the DRM engine plugin using the method
* {@link #provideKeyResponse}.
*
* @param scope may be a sessionId or a keySetId, depending on the specified keyType.
* When the keyType is KEY_TYPE_STREAMING or KEY_TYPE_OFFLINE,
* scope should be set to the sessionId the keys will be provided to. When the keyType
* is KEY_TYPE_RELEASE, scope should be set to the keySetId of the keys
* being released. Releasing keys from a device invalidates them for all sessions.
* @param init container-specific data, its meaning is interpreted based on the
* mime type provided in the mimeType parameter. It could contain, for example,
* the content ID, key ID or other data obtained from the content metadata that is
* required in generating the key request. init may be null when keyType is
* KEY_TYPE_RELEASE.
* @param mimeType identifies the mime type of the content
* @param keyType specifes the type of the request. The request may be to acquire
* keys for streaming or offline content, or to release previously acquired
* keys, which are identified by a keySetId.
* @param optionalParameters are included in the key request message to
* allow a client application to provide additional message parameters to the server.
*
* @throws NotProvisionedException if reprovisioning is needed, due to a
* problem with the certifcate
*/
public native KeyRequest getKeyRequest(byte[] scope, byte[] init,
String mimeType, int keyType,
HashMap optionalParameters)
throws NotProvisionedException;
/**
* A key response is received from the license server by the app, then it is
* provided to the DRM engine plugin using provideKeyResponse. When the
* response is for an offline key request, a keySetId is returned that can be
* used to later restore the keys to a new session with the method
* {@link #restoreKeys}.
* When the response is for a streaming or release request, null is returned.
*
* @param scope may be a sessionId or keySetId depending on the type of the
* response. Scope should be set to the sessionId when the response is for either
* streaming or offline key requests. Scope should be set to the keySetId when
* the response is for a release request.
* @param response the byte array response from the server
*
* @throws NotProvisionedException if the response indicates that
* reprovisioning is required
* @throws DeniedByServerException if the response indicates that the
* server rejected the request
* @throws ResourceBusyException if required resources are in use
*/
public native byte[] provideKeyResponse(byte[] scope, byte[] response)
throws NotProvisionedException, DeniedByServerException;
/**
* Restore persisted offline keys into a new session. keySetId identifies the
* keys to load, obtained from a prior call to {@link #provideKeyResponse}.
*
* @param sessionId the session ID for the DRM session
* @param keySetId identifies the saved key set to restore
*/
public native void restoreKeys(byte[] sessionId, byte[] keySetId);
/**
* Remove the current keys from a session.
*
* @param sessionId the session ID for the DRM session
*/
public native void removeKeys(byte[] sessionId);
/**
* Request an informative description of the key status for the session. The status is
* in the form of {name, value} pairs. Since DRM license policies vary by vendor,
* the specific status field names are determined by each DRM vendor. Refer to your
* DRM provider documentation for definitions of the field names for a particular
* DRM engine plugin.
*
* @param sessionId the session ID for the DRM session
*/
public native HashMap queryKeyStatus(byte[] sessionId);
/**
* Contains the opaque data an app uses to request a certificate from a provisioning
* server
*/
public final static class ProvisionRequest {
ProvisionRequest() {}
/**
* Get the opaque message data
*/
public byte[] getData() { return mData; }
/**
* Get the default URL to use when sending the provision request
* message to a server, if known. The app may prefer to use a different
* provisioning server URL obtained from other sources.
*/
public String getDefaultUrl() { return mDefaultUrl; }
private byte[] mData;
private String mDefaultUrl;
}
/**
* A provision request/response exchange occurs between the app and a provisioning
* server to retrieve a device certificate. If provisionining is required, the
* EVENT_PROVISION_REQUIRED event will be sent to the event handler.
* getProvisionRequest is used to obtain the opaque provision request byte array that
* should be delivered to the provisioning server. The provision request byte array
* is returned in ProvisionRequest.data. The recommended URL to deliver the provision
* request to is returned in ProvisionRequest.defaultUrl.
*/
public native ProvisionRequest getProvisionRequest();
/**
* After a provision response is received by the app, it is provided to the DRM
* engine plugin using this method.
*
* @param response the opaque provisioning response byte array to provide to the
* DRM engine plugin.
*
* @throws DeniedByServerException if the response indicates that the
* server rejected the request
*/
public native void provideProvisionResponse(byte[] response)
throws DeniedByServerException;
/**
* A means of enforcing limits on the number of concurrent streams per subscriber
* across devices is provided via SecureStop. This is achieved by securely
* monitoring the lifetime of sessions.
*
* Information from the server related to the current playback session is written
* to persistent storage on the device when each MediaCrypto object is created.
*
* In the normal case, playback will be completed, the session destroyed and the
* Secure Stops will be queried. The app queries secure stops and forwards the
* secure stop message to the server which verifies the signature and notifies the
* server side database that the session destruction has been confirmed. The persisted
* record on the client is only removed after positive confirmation that the server
* received the message using releaseSecureStops().
*/
public native List getSecureStops();
/**
* Process the SecureStop server response message ssRelease. After authenticating
* the message, remove the SecureStops identified in the response.
*
* @param ssRelease the server response indicating which secure stops to release
*/
public native void releaseSecureStops(byte[] ssRelease);
/**
* String property name: identifies the maker of the DRM engine plugin
*/
public static final String PROPERTY_VENDOR = "vendor";
/**
* String property name: identifies the version of the DRM engine plugin
*/
public static final String PROPERTY_VERSION = "version";
/**
* String property name: describes the DRM engine plugin
*/
public static final String PROPERTY_DESCRIPTION = "description";
/**
* String property name: a comma-separated list of cipher and mac algorithms
* supported by CryptoSession. The list may be empty if the DRM engine
* plugin does not support CryptoSession operations.
*/
public static final String PROPERTY_ALGORITHMS = "algorithms";
/**
* Read a DRM engine plugin String property value, given the property name string.
*
* Standard fields names are:
* {@link #PROPERTY_VENDOR}, {@link #PROPERTY_VERSION},
* {@link #PROPERTY_DESCRIPTION}, {@link #PROPERTY_ALGORITHMS}
*/
public native String getPropertyString(String propertyName);
/**
* Byte array property name: the device unique identifier is established during
* device provisioning and provides a means of uniquely identifying each device.
*/
public static final String PROPERTY_DEVICE_UNIQUE_ID = "deviceUniqueId";
/**
* Read a DRM engine plugin byte array property value, given the property name string.
*
* Standard fields names are {@link #PROPERTY_DEVICE_UNIQUE_ID}
*/
public native byte[] getPropertyByteArray(String propertyName);
/**
* Set a DRM engine plugin String property value.
*/
public native void setPropertyString(String propertyName, String value);
/**
* Set a DRM engine plugin byte array property value.
*/
public native void setPropertyByteArray(String propertyName, byte[] value);
private static final native void setCipherAlgorithmNative(MediaDrm drm, byte[] sessionId,
String algorithm);
private static final native void setMacAlgorithmNative(MediaDrm drm, byte[] sessionId,
String algorithm);
private static final native byte[] encryptNative(MediaDrm drm, byte[] sessionId,
byte[] keyId, byte[] input, byte[] iv);
private static final native byte[] decryptNative(MediaDrm drm, byte[] sessionId,
byte[] keyId, byte[] input, byte[] iv);
private static final native byte[] signNative(MediaDrm drm, byte[] sessionId,
byte[] keyId, byte[] message);
private static final native boolean verifyNative(MediaDrm drm, byte[] sessionId,
byte[] keyId, byte[] message,
byte[] signature);
/**
* In addition to supporting decryption of DASH Common Encrypted Media, the
* MediaDrm APIs provide the ability to securely deliver session keys from
* an operator's session key server to a client device, based on the factory-installed
* root of trust, and then perform encrypt, decrypt, sign and verify operations
* with the session key on arbitrary user data.
*
* The CryptoSession class implements generic encrypt/decrypt/sign/verify methods
* based on the established session keys. These keys are exchanged using the
* getKeyRequest/provideKeyResponse methods.
*
* Applications of this capability could include securing various types of
* purchased or private content, such as applications, books and other media,
* photos or media delivery protocols.
*
* Operators can create session key servers that are functionally similar to a
* license key server, except that instead of receiving license key requests and
* providing encrypted content keys which are used specifically to decrypt A/V media
* content, the session key server receives session key requests and provides
* encrypted session keys which can be used for general purpose crypto operations.
*
* A CryptoSession is obtained using {@link #getCryptoSession}
*/
public final class CryptoSession {
private MediaDrm mDrm;
private byte[] mSessionId;
CryptoSession(MediaDrm drm, byte[] sessionId,
String cipherAlgorithm, String macAlgorithm)
{
mSessionId = sessionId;
mDrm = drm;
setCipherAlgorithmNative(drm, sessionId, cipherAlgorithm);
setMacAlgorithmNative(drm, sessionId, macAlgorithm);
}
/**
* Encrypt data using the CryptoSession's cipher algorithm
*
* @param keyid specifies which key to use
* @param input the data to encrypt
* @param iv the initialization vector to use for the cipher
*/
public byte[] encrypt(byte[] keyid, byte[] input, byte[] iv) {
return encryptNative(mDrm, mSessionId, keyid, input, iv);
}
/**
* Decrypt data using the CryptoSessions's cipher algorithm
*
* @param keyid specifies which key to use
* @param input the data to encrypt
* @param iv the initialization vector to use for the cipher
*/
public byte[] decrypt(byte[] keyid, byte[] input, byte[] iv) {
return decryptNative(mDrm, mSessionId, keyid, input, iv);
}
/**
* Sign data using the CryptoSessions's mac algorithm.
*
* @param keyid specifies which key to use
* @param message the data for which a signature is to be computed
*/
public byte[] sign(byte[] keyid, byte[] message) {
return signNative(mDrm, mSessionId, keyid, message);
}
/**
* Verify a signature using the CryptoSessions's mac algorithm. Return true
* if the signatures match, false if they do no.
*
* @param keyid specifies which key to use
* @param message the data to verify
* @param signature the reference signature which will be compared with the
* computed signature
*/
public boolean verify(byte[] keyid, byte[] message, byte[] signature) {
return verifyNative(mDrm, mSessionId, keyid, message, signature);
}
};
/**
* Obtain a CryptoSession object which can be used to encrypt, decrypt,
* sign and verify messages or data using the session keys established
* for the session using methods {@link #getKeyRequest} and
* {@link #provideKeyResponse} using a session key server.
*
* @param sessionId the session ID for the session containing keys
* to be used for encrypt, decrypt, sign and/or verify
* @param cipherAlgorithm the algorithm to use for encryption and
* decryption ciphers. The algorithm string conforms to JCA Standard
* Names for Cipher Transforms and is case insensitive. For example
* "AES/CBC/NoPadding".
* @param macAlgorithm the algorithm to use for sign and verify
* The algorithm string conforms to JCA Standard Names for Mac
* Algorithms and is case insensitive. For example "HmacSHA256".
*
* The list of supported algorithms for a DRM engine plugin can be obtained
* using the method {@link #getPropertyString} with the property name
* "algorithms".
*/
public CryptoSession getCryptoSession(byte[] sessionId,
String cipherAlgorithm,
String macAlgorithm)
{
return new CryptoSession(this, sessionId, cipherAlgorithm, macAlgorithm);
}
@Override
protected void finalize() {
native_finalize();
}
public native final void release();
private static native final void native_init();
private native final void native_setup(Object mediadrm_this, byte[] uuid);
private native final void native_finalize();
static {
System.loadLibrary("media_jni");
native_init();
}
}