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package moe.yuuta.gplicense;
import android.text.TextUtils;
import com.elvishew.xlog.Logger;
import com.elvishew.xlog.XLog;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import moe.yuuta.gplicense.util.Base64;
import moe.yuuta.gplicense.util.Base64DecoderException;
/**
* Contains data related to a licensing request and methods to verify
* and process the response.
*/
class LicenseValidator {
private final Logger logger = XLog.tag("LVter").build();
// Server response codes.
private static final int LICENSED = 0x0;
private static final int NOT_LICENSED = 0x1;
private static final int LICENSED_OLD_KEY = 0x2;
private static final int ERROR_NOT_MARKET_MANAGED = 0x3;
private static final int ERROR_SERVER_FAILURE = 0x4;
private static final int ERROR_OVER_QUOTA = 0x5;
private static final int ERROR_CONTACTING_SERVER = 0x101;
private static final int ERROR_INVALID_PACKAGE_NAME = 0x102;
private static final int ERROR_NON_MATCHING_UID = 0x103;
private final Policy mPolicy;
private final LicenseCheckerCallback mCallback;
private final int mNonce;
private final String mPackageName;
private final String mVersionCode;
private final DeviceLimiter mDeviceLimiter;
LicenseValidator(Policy policy, DeviceLimiter deviceLimiter, LicenseCheckerCallback callback,
int nonce, String packageName, String versionCode) {
mPolicy = policy;
mDeviceLimiter = deviceLimiter;
mCallback = callback;
mNonce = nonce;
mPackageName = packageName;
mVersionCode = versionCode;
}
public LicenseCheckerCallback getCallback() {
return mCallback;
}
public int getNonce() {
return mNonce;
}
public String getPackageName() {
return mPackageName;
}
private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
/**
* Verifies the response from server and calls appropriate callback method.
*
* @param publicKey public key associated with the developer account
* @param responseCode server response code
* @param signedData signed data from server
* @param signature server signature
*/
public void verify(PublicKey publicKey, int responseCode, String signedData, String signature) {
String userId = null;
// Skip signature check for unsuccessful requests
ResponseData data = null;
if (responseCode == LICENSED || responseCode == NOT_LICENSED ||
responseCode == LICENSED_OLD_KEY) {
// Verify signature.
try {
if (TextUtils.isEmpty(signedData)) {
logger.e("Signature verification failed: signedData is empty. " +
"(Device not signed-in to any Google accounts?)");
handleInvalidResponse();
return;
}
Signature sig = Signature.getInstance(SIGNATURE_ALGORITHM);
sig.initVerify(publicKey);
sig.update(signedData.getBytes());
if (!sig.verify(Base64.decode(signature))) {
logger.e("Signature verification failed.");
handleInvalidResponse();
return;
}
} catch (NoSuchAlgorithmException e) {
// This can't happen on an Android compatible device.
throw new RuntimeException(e);
} catch (InvalidKeyException e) {
handleApplicationError(LicenseCheckerCallback.ERROR_INVALID_PUBLIC_KEY);
return;
} catch (SignatureException e) {
throw new RuntimeException(e);
} catch (Base64DecoderException e) {
logger.e("Could not Base64-decode signature.");
handleInvalidResponse();
return;
}
// Parse and validate response.
try {
data = ResponseData.parse(signedData);
} catch (IllegalArgumentException e) {
logger.e("Could not parse response.");
handleInvalidResponse();
return;
}
if (data.responseCode != responseCode) {
logger.e("Response codes don't match.");
handleInvalidResponse();
return;
}
if (data.nonce != mNonce) {
logger.e("Nonce doesn't match.");
handleInvalidResponse();
return;
}
if (!data.packageName.equals(mPackageName)) {
logger.e("Package name doesn't match.");
handleInvalidResponse();
return;
}
if (!data.versionCode.equals(mVersionCode)) {
logger.e("Version codes don't match.");
handleInvalidResponse();
return;
}
// Application-specific user identifier.
userId = data.userId;
if (TextUtils.isEmpty(userId)) {
logger.e("User identifier is empty.");
handleInvalidResponse();
return;
}
}
logger.d("Final code: " + responseCode);
switch (responseCode) {
case LICENSED:
case LICENSED_OLD_KEY:
int limiterResponse = mDeviceLimiter.isDeviceAllowed(userId);
handleResponse(limiterResponse, data);
break;
case NOT_LICENSED:
handleResponse(Policy.NOT_LICENSED, data);
break;
case ERROR_CONTACTING_SERVER:
logger.w("Error contacting licensing server.");
handleResponse(Policy.RETRY, data);
break;
case ERROR_SERVER_FAILURE:
logger.w("An error has occurred on the licensing server.");
handleResponse(Policy.RETRY, data);
break;
case ERROR_OVER_QUOTA:
logger.w("Licensing server is refusing to talk to this device, over quota.");
handleResponse(Policy.RETRY, data);
break;
case ERROR_INVALID_PACKAGE_NAME:
handleApplicationError(LicenseCheckerCallback.ERROR_INVALID_PACKAGE_NAME);
break;
case ERROR_NON_MATCHING_UID:
handleApplicationError(LicenseCheckerCallback.ERROR_NON_MATCHING_UID);
break;
case ERROR_NOT_MARKET_MANAGED:
handleApplicationError(LicenseCheckerCallback.ERROR_NOT_MARKET_MANAGED);
break;
default:
logger.e("Unknown response code for checking.");
handleInvalidResponse();
}
}
/**
* Confers with policy and calls appropriate callback method.
*
* @param response
* @param rawData
*/
private void handleResponse(int response, ResponseData rawData) {
logger.d("handle: " + response);
// Update policy data and increment retry counter (if needed)
mPolicy.processServerResponse(response, rawData);
// Given everything we know, including cached data, ask the policy if we should grant
// access.
if (mPolicy.allowAccess()) {
mCallback.allow(response);
} else {
mCallback.dontAllow(response);
}
}
private void handleApplicationError(int code) {
mCallback.applicationError(code);
}
private void handleInvalidResponse() {
mCallback.dontAllow(Policy.NOT_LICENSED);
}
}
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