/*
* Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 main.java.com.amazonaws.cognito.devauthsample;
import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import com.amazonaws.services.cognitoidentity.model.GetOpenIdTokenForDeveloperIdentityResult;
import com.amazonaws.util.DateUtils;
import com.amazonaws.util.HttpUtils;
public class Utilities {
protected static final Logger log = AWSCognitoDeveloperAuthenticationSampleLogger.getLogger();
private static SecureRandom RANDOM = new SecureRandom();
static {
RANDOM.generateSeed(16);
}
public static String prepareJsonResponseForTokens(GetOpenIdTokenForDeveloperIdentityResult result, String key) {
StringBuilder responseBody = new StringBuilder();
responseBody.append("{");
responseBody.append("\t\"identityPoolId\": \"").append(Configuration.IDENTITY_POOL_ID).append("\",");
responseBody.append("\t\"identityId\": \"").append(result.getIdentityId()).append("\",");
responseBody.append("\t\"token\": \"").append(result.getToken()).append("\",");
responseBody.append("}");
// Encrypting the response
return AESEncryption.wrap(responseBody.toString(), key);
}
public static String prepareJsonResponseForKey(String data, String key) {
StringBuilder responseBody = new StringBuilder();
responseBody.append("{");
responseBody.append("\t\"key\": \"").append(data).append("\"");
responseBody.append("}");
// Encrypting the response
return AESEncryption.wrap(responseBody.toString(), key.substring(0, 32));
}
public static String sign(String content, String key) {
try {
byte[] data = content.getBytes(Constants.ENCODING_FORMAT);
Mac mac = Mac.getInstance(Constants.SIGNATURE_METHOD);
mac.init(new SecretKeySpec(key.getBytes(Constants.ENCODING_FORMAT), Constants.SIGNATURE_METHOD));
char[] signature = Hex.encodeHex(mac.doFinal(data));
return new String(signature);
} catch (Exception e) {
log.log(Level.SEVERE, "Exception during sign", e);
}
return null;
}
public static String getSaltedPassword(String username, String endPointUri, String password) {
return sign((username + Configuration.APP_NAME + endPointUri.toLowerCase()), password);
}
public static String base64(String data) throws UnsupportedEncodingException {
byte[] signature = Base64.encodeBase64(data.getBytes(Constants.ENCODING_FORMAT));
return new String(signature, Constants.ENCODING_FORMAT);
}
public static String getEndPoint(HttpServletRequest request) {
if (null == request) {
return null;
}
else {
String endpoint = request.getServerName().toLowerCase();
log.info("Endpoint : " + encode(endpoint));
return endpoint;
}
}
/**
* Checks to see if the request has valid timestamp. If given timestamp
* falls in 30 mins window from current server timestamp
*/
public static boolean isTimestampValid(String timestamp) {
long timestampLong = 0L;
final long window = 15 * 60 * 1000L;
if (null == timestamp) {
return false;
}
timestampLong = DateUtils.parseISO8601Date(timestamp).getTime();
Long now = new Date().getTime();
long before15Mins = new Date(now - window).getTime();
long after15Mins = new Date(now + window).getTime();
return (timestampLong >= before15Mins && timestampLong <= after15Mins);
}
public static String generateRandomString() {
byte[] randomBytes = new byte[16];
RANDOM.nextBytes(randomBytes);
String randomString = new String(Hex.encodeHex(randomBytes));
return randomString;
}
public static boolean isValidUsername(String username) {
int length = username.length();
if (length < 3 || length > 128) {
return false;
}
char c = 0;
for (int i = 0; i < length; i++) {
c = username.charAt(i);
if (!Character.isLetterOrDigit(c) && '_' != c && '.' != c && '@' != c) {
return false;
}
}
return true;
}
public static boolean isValidPassword(String password) {
int length = password.length();
return (length >= 6 && length <= 128);
}
public static boolean isEmpty(String str) {
if (null == str || str.trim().length() == 0)
return true;
return false;
}
public static String encode(String s) {
if (null == s)
return s;
return HttpUtils.urlEncode(s, false);
}
/**
* This method is low performance string comparison function. The purpose of
* this method is to prevent timing attack.
*/
public static boolean slowStringComparison(String givenSignature, String computedSignature) {
if (null == givenSignature || null == computedSignature
|| givenSignature.length() != computedSignature.length())
return false;
int n = computedSignature.length();
boolean signaturesMatch = true;
for (int i = 0; i < n; i++) {
signaturesMatch &= (computedSignature.charAt(i) == givenSignature.charAt(i));
}
return signaturesMatch;
}
/**
* Extract element from a JSON string
*
* @param json
* A string of JSON blob
* @param element
* JSON key
* @return the corresponding string value of the element
*/
public static String extractElement(String json, String element) {
boolean hasElement = (json.indexOf(element) != -1);
if (hasElement) {
int elementIndex = json.indexOf(element) + element.length() + 1;
int startIndex = json.indexOf("\"", elementIndex);
int endIndex = json.indexOf("\"", startIndex + 1);
return json.substring(startIndex + 1, endIndex);
}
return null;
}
}
