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Add download request tokens and enforce destination clear

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Start writing tokens for each download request after calling download(),
and check agains them when a completed-file intent is received with a
download request extra.
Also start checking that the download destination is clear.

Change-Id: I533fe2ba49ac56bed5eab44670fe8e9a273b1ffb
This commit is contained in:
Hall Liu
2017-06-19 17:20:10 -07:00
parent e601160a96
commit 2043f70acb
4 changed files with 136 additions and 33 deletions
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68
telephony/java/android/telephony/MbmsDownloadManager.java
View File

@@ -388,21 +388,10 @@ public class MbmsDownloadManager {
tempRootDirectory.mkdirs();
setTempFileRootDirectory(tempRootDirectory);
}
request.setAppName(mDownloadAppName);
// Check if the request is a multipart download. If so, validate that the destination is
// a directory that exists.
// TODO: figure out what qualifies a request as a multipart download request.
if (request.getSourceUri().getLastPathSegment() != null &&
request.getSourceUri().getLastPathSegment().contains("*")) {
File toFile = new File(request.getDestinationUri().getSchemeSpecificPart());
if (!toFile.isDirectory()) {
throw new IllegalArgumentException("Multipart download must specify valid " +
"destination directory.");
}
}
// TODO: check to make sure destination is clear
// TODO: write download request token
checkValidDownloadDestination(request);
writeDownloadRequestToken(request);
try {
downloadService.download(request, callback);
} catch (RemoteException e) {
@@ -435,6 +424,7 @@ public class MbmsDownloadManager {
* <li>ERROR_MSDC_UNKNOWN_REQUEST</li>
*/
public int cancelDownload(DownloadRequest downloadRequest) {
// TODO: don't forget to delete the token
return 0;
}
@@ -518,4 +508,54 @@ public class MbmsDownloadManager {
Log.i(LOG_TAG, "Remote exception while disposing of service");
}
}
private void writeDownloadRequestToken(DownloadRequest request) {
// TODO: figure out when this token eventually gets deleted
File tempFileLocation = MbmsUtils.getEmbmsTempFileDirForRequest(mContext, request);
if (!tempFileLocation.exists()) {
tempFileLocation.mkdirs();
}
String downloadTokenFileName = request.getHash()
+ MbmsDownloadReceiver.DOWNLOAD_TOKEN_SUFFIX;
File token = new File(tempFileLocation, downloadTokenFileName);
if (token.exists()) {
Log.w(LOG_TAG, "Download token " + downloadTokenFileName + " already exists");
return;
}
try {
if (!token.createNewFile()) {
throw new RuntimeException("Failed to create download token for request "
+ request);
}
} catch (IOException e) {
throw new RuntimeException("Failed to create download token for request " + request
+ " due to IOException " + e);
}
}
/**
* Verifies the following:
* If a request is multi-part,
* 1. Destination Uri must exist and be a directory
* 2. Directory specified must contain no files.
* Otherwise
* 1. The file specified by the destination Uri must not exist.
*/
private void checkValidDownloadDestination(DownloadRequest request) {
File toFile = new File(request.getDestinationUri().getSchemeSpecificPart());
if (request.isMultipartDownload()) {
if (!toFile.isDirectory()) {
throw new IllegalArgumentException("Multipart download must specify valid " +
"destination directory.");
}
if (toFile.listFiles().length > 0) {
throw new IllegalArgumentException("Destination directory must be clear of all " +
"files.");
}
} else {
if (toFile.exists()) {
throw new IllegalArgumentException("Destination file must not exist.");
}
}
}
}

57
telephony/java/android/telephony/mbms/DownloadRequest.java
View File

@@ -20,15 +20,22 @@ import android.content.Intent;
import android.net.Uri;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.Base64;
import java.lang.IllegalStateException;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* A Parcelable class describing a pending Cell-Broadcast download request
* @hide
*/
public class DownloadRequest implements Parcelable {
// Version code used to keep token calculation consistent.
private static final int CURRENT_VERSION = 1;
/** @hide */
public static class Builder {
private int id;
@@ -37,6 +44,7 @@ public class DownloadRequest implements Parcelable {
private Uri dest;
private int subscriptionId;
private String appIntent;
private int version = CURRENT_VERSION;
public Builder setId(int id) {
this.id = id;
@@ -68,9 +76,14 @@ public class DownloadRequest implements Parcelable {
return this;
}
public Builder setVersion(int version) {
this.version = version;
return this;
}
public DownloadRequest build() {
return new DownloadRequest(id, serviceInfo, source, dest,
subscriptionId, appIntent, null);
subscriptionId, appIntent, null, version);
}
}
@@ -80,11 +93,12 @@ public class DownloadRequest implements Parcelable {
private final Uri destinationUri;
private final int subscriptionId;
private final String serializedResultIntentForApp;
private final int version;
private String appName; // not the Android app Name, the embms app name
private DownloadRequest(int id, FileServiceInfo serviceInfo,
Uri source, Uri dest,
int sub, String appIntent, String name) {
int sub, String appIntent, String name, int version) {
downloadId = id;
fileServiceInfo = serviceInfo;
sourceUri = source;
@@ -92,6 +106,7 @@ public class DownloadRequest implements Parcelable {
subscriptionId = sub;
serializedResultIntentForApp = appIntent;
appName = name;
this.version = version;
}
public static DownloadRequest copy(DownloadRequest other) {
@@ -106,6 +121,7 @@ public class DownloadRequest implements Parcelable {
subscriptionId = dr.subscriptionId;
serializedResultIntentForApp = dr.serializedResultIntentForApp;
appName = dr.appName;
version = dr.version;
}
private DownloadRequest(Parcel in) {
@@ -116,6 +132,7 @@ public class DownloadRequest implements Parcelable {
subscriptionId = in.readInt();
serializedResultIntentForApp = in.readString();
appName = in.readString();
version = in.readInt();
}
public int describeContents() {
@@ -130,6 +147,7 @@ public class DownloadRequest implements Parcelable {
out.writeInt(subscriptionId);
out.writeString(serializedResultIntentForApp);
out.writeString(appName);
out.writeInt(version);
}
public int getDownloadId() {
@@ -172,6 +190,10 @@ public class DownloadRequest implements Parcelable {
return appName;
}
public int getVersion() {
return version;
}
public static final Parcelable.Creator<DownloadRequest> CREATOR =
new Parcelable.Creator<DownloadRequest>() {
public DownloadRequest createFromParcel(Parcel in) {
@@ -181,4 +203,35 @@ public class DownloadRequest implements Parcelable {
return new DownloadRequest[size];
}
};
/**
* @hide
*/
public boolean isMultipartDownload() {
// TODO: figure out what qualifies a request as a multipart download request.
return getSourceUri().getLastPathSegment() != null &&
getSourceUri().getLastPathSegment().contains("*");
}
/**
* Retrieves the hash string that should be used as the filename when storing a token for
* this DownloadRequest.
* @hide
*/
public String getHash() {
MessageDigest digest;
try {
digest = MessageDigest.getInstance("SHA-256");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Could not get sha256 hash object");
}
if (version >= 1) {
// Hash the source URI, destination URI, and the app intent
digest.update(sourceUri.toString().getBytes(StandardCharsets.UTF_8));
digest.update(destinationUri.toString().getBytes(StandardCharsets.UTF_8));
digest.update(serializedResultIntentForApp.getBytes(StandardCharsets.UTF_8));
}
// Add updates for future versions here
return Base64.encodeToString(digest.digest(), Base64.URL_SAFE | Base64.NO_WRAP);
}
}

34
telephony/java/android/telephony/mbms/MbmsDownloadReceiver.java
View File

@@ -41,6 +41,7 @@ import java.util.UUID;
public class MbmsDownloadReceiver extends BroadcastReceiver {
private static final String LOG_TAG = "MbmsDownloadReceiver";
private static final String TEMP_FILE_SUFFIX = ".embms.temp";
public static final String DOWNLOAD_TOKEN_SUFFIX = ".download_token";
private static final int MAX_TEMP_FILE_RETRIES = 5;
public static final String MBMS_FILE_PROVIDER_META_DATA_KEY = "mbms-file-provider-authority";
@@ -50,7 +51,7 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (!verifyIntentContents(intent)) {
if (!verifyIntentContents(context, intent)) {
setResultCode(1 /* TODO: define error constants */);
return;
}
@@ -69,7 +70,7 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
// TODO: Add handling for ACTION_CLEANUP
}
private boolean verifyIntentContents(Intent intent) {
private boolean verifyIntentContents(Context context, Intent intent) {
if (MbmsDownloadManager.ACTION_DOWNLOAD_RESULT_INTERNAL.equals(intent.getAction())) {
if (!intent.hasExtra(MbmsDownloadManager.EXTRA_RESULT)) {
Log.w(LOG_TAG, "Download result did not include a result code. Ignoring.");
@@ -93,8 +94,19 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
"temp file. Ignoring.");
return false;
}
DownloadRequest request = intent.getParcelableExtra(MbmsDownloadManager.EXTRA_REQUEST);
String expectedTokenFileName = request.getHash() + DOWNLOAD_TOKEN_SUFFIX;
File expectedTokenFile = new File(
MbmsUtils.getEmbmsTempFileDirForRequest(context, request),
expectedTokenFileName);
if (!expectedTokenFile.exists()) {
Log.w(LOG_TAG, "Supplied download request does not match a token that we have. " +
"Expected " + expectedTokenFile);
return false;
}
return true;
} else if (MbmsDownloadManager.ACTION_FILE_DESCRIPTOR_REQUEST.equals(intent.getAction())) {
// TODO: get rid of the request argument for a file descriptor request.
if (!intent.hasExtra(MbmsDownloadManager.EXTRA_REQUEST)) {
Log.w(LOG_TAG, "Temp file request not include the associated request. Ignoring.");
return false;
@@ -112,7 +124,6 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
private void moveDownloadedFile(Context context, Intent intent) {
DownloadRequest request = intent.getParcelableExtra(MbmsDownloadManager.EXTRA_REQUEST);
// TODO: check request against token
Intent intentForApp = request.getIntentForApp();
int result = intent.getIntExtra(MbmsDownloadManager.EXTRA_RESULT,
@@ -149,7 +160,6 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
}
private void cleanupPostMove(Context context, Intent intent) {
// TODO: account for in-use temp files
DownloadRequest request = intent.getParcelableExtra(MbmsDownloadManager.EXTRA_REQUEST);
if (request == null) {
Log.w(LOG_TAG, "Intent does not include a DownloadRequest. Ignoring.");
@@ -199,7 +209,7 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
private ArrayList<UriPathPair> generateFreshTempFiles(Context context, DownloadRequest request,
int freshFdCount) {
File tempFileDir = getEmbmsTempFileDirForRequest(context, request);
File tempFileDir = MbmsUtils.getEmbmsTempFileDirForRequest(context, request);
if (!tempFileDir.exists()) {
tempFileDir.mkdirs();
}
@@ -345,24 +355,14 @@ public class MbmsDownloadReceiver extends BroadcastReceiver {
return false;
}
if (!MbmsUtils.isContainedIn(getEmbmsTempFileDirForRequest(context, request), tempFile)) {
if (!MbmsUtils.isContainedIn(
MbmsUtils.getEmbmsTempFileDirForRequest(context, request), tempFile)) {
return false;
}
return true;
}
/**
* Returns a File linked to the directory used to store temp files for this request
*/
private static File getEmbmsTempFileDirForRequest(Context context, DownloadRequest request) {
File embmsTempFileDir = MbmsTempFileProvider.getEmbmsTempFileDir(context);
// TODO: better naming scheme for temp file dirs
String tempFileDirName = String.valueOf(request.getFileServiceInfo().getServiceId());
return new File(embmsTempFileDir, tempFileDirName);
}
private String getFileProviderAuthorityCached(Context context) {
if (mFileProviderAuthorityCache != null) {
return mFileProviderAuthorityCache;

10
telephony/java/android/telephony/mbms/MbmsUtils.java
View File

@@ -85,4 +85,14 @@ public class MbmsUtils {
context.bindService(bindIntent, serviceConnection, Context.BIND_AUTO_CREATE);
}
/**
* Returns a File linked to the directory used to store temp files for this request
*/
public static File getEmbmsTempFileDirForRequest(Context context, DownloadRequest request) {
File embmsTempFileDir = MbmsTempFileProvider.getEmbmsTempFileDir(context);
String tempFileDirName = String.valueOf(request.getFileServiceInfo().getServiceId());
return new File(embmsTempFileDir, tempFileDirName);
}
}