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Fix issues pointed out by code review
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@vanitasvitae
vanitasvitae committed May 16, 2019
1 parent eef6d59 commit be5f811
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Showing 11 changed files with 510 additions and 306 deletions.
36 changes: 36 additions & 0 deletions smack-core/src/main/java/org/jivesoftware/smack/util/RandomUtils.java
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@@ -0,0 +1,36 @@
/**
*
* Copyright © 2019 Paul Schaub
*
* 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 org.jivesoftware.smack.util;

import java.security.SecureRandom;

public class RandomUtils {

private static final SecureRandom SECURE_RANDOM = new SecureRandom();

/**
* Generate a securely random byte array.
*
* @param len length of the byte array
* @return byte array
*/
public static byte[] secureRandomBytes(int len) {
byte[] bytes = new byte[len];
SECURE_RANDOM.nextBytes(bytes);
return bytes;
}
}
3 changes: 2 additions & 1 deletion smack-core/src/main/java/org/jivesoftware/smack/util/StringUtils.java
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Expand Up @@ -246,7 +246,8 @@ public static String encodeHex(byte[] bytes) {

/**
* Convert a hexadecimal String to bytes.
* Stolen from https://stackoverflow.com/a/140861/11150851
*
* Source: https://stackoverflow.com/a/140861/11150851
*
* @param s hex string
* @return byte array
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241 changes: 2 additions & 239 deletions ...erimental/src/main/java/org/jivesoftware/smackx/httpfileupload/HttpFileUploadManager.java
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Expand Up @@ -24,12 +24,10 @@
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
Expand All @@ -38,11 +36,7 @@
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
Expand All @@ -55,14 +49,14 @@
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPConnectionRegistry;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.util.Objects;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
import org.jivesoftware.smackx.disco.packet.DiscoverInfo;
import org.jivesoftware.smackx.httpfileupload.UploadService.Version;
import org.jivesoftware.smackx.httpfileupload.element.Slot;
import org.jivesoftware.smackx.httpfileupload.element.SlotRequest;
import org.jivesoftware.smackx.httpfileupload.element.SlotRequest_V0_2;
import org.jivesoftware.smackx.omemo_media_sharing.AesgcmUrl;
import org.jivesoftware.smackx.omemo_media_sharing.OmemoMediaSharingUtils;
import org.jivesoftware.smackx.xdata.FormField;
import org.jivesoftware.smackx.xdata.packet.DataForm;

Expand Down Expand Up @@ -95,7 +89,6 @@ public final class HttpFileUploadManager extends Manager {
public static final String NAMESPACE_0_2 = "urn:xmpp:http:upload";

private static final Logger LOGGER = Logger.getLogger(HttpFileUploadManager.class.getName());
private static final SecureRandom SECURE_RANDOM = new SecureRandom();

static {
XMPPConnectionRegistry.addConnectionCreationListener(new ConnectionCreationListener() {
Expand Down Expand Up @@ -579,234 +572,4 @@ public static UploadService.Version namespaceToVersion(String namespace) {
private static boolean containsHttpFileUploadNamespace(DiscoverInfo discoverInfo) {
return discoverInfo.containsFeature(NAMESPACE) || discoverInfo.containsFeature(NAMESPACE_0_2);
}

/**
* Generate a securely random byte array.
*
* @param len length of the byte array
* @return byte array
*/
private static byte[] secureRandomBytes(int len) {
byte[] bytes = new byte[len];
SECURE_RANDOM.nextBytes(bytes);
return bytes;
}

/**
* Utility code for XEP-XXXX: OMEMO Media Sharing.
*
* @see <a href="https://xmpp.org/extensions/inbox/omemo-media-sharing.html">XEP-XXXX: OMEMO Media Sharing</a>
*/
static class OmemoMediaSharingUtils {

private static final String KEYTYPE = "AES";
private static final String CIPHERMODE = "AES/GCM/NoPadding";
// 256 bit = 32 byte
private static final int LEN_KEY = 32;
private static final int LEN_KEY_BITS = LEN_KEY * 8;

private static final int LEN_IV_12 = 12;
private static final int LEN_IV_16 = 16;
// Note: Contrary to what the ProtoXEP states, 16 byte IV length is used in the wild instead of 12.
// At some point we should switch to 12 bytes though.
private static final int LEN_IV = LEN_IV_16;

static byte[] generateRandomIV() {
return generateRandomIV(LEN_IV);
}

static byte[] generateRandomIV(int len) {
return secureRandomBytes(len);
}

/**
* Generate a random 256 bit AES key.
*
* @return encoded AES key
* @throws NoSuchAlgorithmException if the JVM doesn't provide the given key type.
*/
static byte[] generateRandomKey() throws NoSuchAlgorithmException {
KeyGenerator generator = KeyGenerator.getInstance(KEYTYPE);
generator.init(LEN_KEY_BITS);
return generator.generateKey().getEncoded();
}

/**
* Create a {@link Cipher} from a given key and iv which is in encryption mode.
*
* @param key aes encryption key
* @param iv initialization vector
*
* @return cipher in encryption mode
*
* @throws NoSuchPaddingException if the JVM doesn't provide the padding specified in the ciphermode.
* @throws NoSuchAlgorithmException if the JVM doesn't provide the encryption method specified in the ciphermode.
* @throws InvalidAlgorithmParameterException if the cipher cannot be initiated.
* @throws InvalidKeyException if the key is invalid.
*/
private static Cipher encryptionCipherFrom(byte[] key, byte[] iv)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
InvalidKeyException {
SecretKey secretKey = new SecretKeySpec(key, KEYTYPE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance(CIPHERMODE);
cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
return cipher;
}

/**
* Create a {@link Cipher} from a given key and iv which is in decryption mode.
*
* @param key aes encryption key
* @param iv initialization vector
*
* @return cipher in decryption mode
*
* @throws NoSuchPaddingException if the JVM doesn't provide the padding specified in the ciphermode.
* @throws NoSuchAlgorithmException if the JVM doesn't provide the encryption method specified in the ciphermode.
* @throws InvalidAlgorithmParameterException if the cipher cannot be initiated.
* @throws InvalidKeyException if the key is invalid.
*/
private static Cipher decryptionCipherFrom(byte[] key, byte[] iv)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
InvalidKeyException {
SecretKey secretKey = new SecretKeySpec(key, KEYTYPE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance(CIPHERMODE);
cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
return cipher;
}
}

/**
* This class represents a aesgcm URL as described in XEP-XXXX: OMEMO Media Sharing.
* As the builtin {@link URL} class cannot handle the aesgcm protocol identifier, this class
* is used as a utility class that bundles together a {@link URL}, key and IV.
*
* @see <a href="https://xmpp.org/extensions/inbox/omemo-media-sharing.html">XEP-XXXX: OMEMO Media Sharing</a>
*/
public static class AesgcmUrl {

public static final String PROTOCOL = "aesgcm";

private final URL httpsUrl;
private final byte[] keyBytes;
private final byte[] ivBytes;

/**
* Private constructor that constructs the {@link AesgcmUrl} from a normal https {@link URL}, a key and iv.
*
* @param httpsUrl normal https url as given by the {@link Slot}.
* @param key byte array of an encoded 256 bit aes key
* @param iv 16 or 12 byte initialization vector
*/
AesgcmUrl(URL httpsUrl, byte[] key, byte[] iv) {
this.httpsUrl = Objects.requireNonNull(httpsUrl);
this.keyBytes = Objects.requireNonNull(key);
this.ivBytes = Objects.requireNonNull(iv);
}

/**
* Parse a {@link AesgcmUrl} from a {@link String}.
* The parsed object will provide a normal {@link URL} under which the offered file can be downloaded,
* as well as a {@link Cipher} that can be used to decrypt it.
*
* @param aesgcmUrlString aesgcm URL as a {@link String}
*/
public AesgcmUrl(String aesgcmUrlString) {
if (!aesgcmUrlString.startsWith(PROTOCOL)) {
throw new IllegalArgumentException("Provided String does not resemble a aesgcm URL.");
}

// Convert aesgcm Url to https URL
this.httpsUrl = extractHttpsUrl(aesgcmUrlString);

// Extract IV and Key
byte[][] ivAndKey = extractIVAndKey(aesgcmUrlString);
this.ivBytes = ivAndKey[0];
this.keyBytes = ivAndKey[1];
}

/**
* Return a https {@link URL} under which the file can be downloaded.
*
* @return https URL
*/
public URL getDownloadUrl() {
return httpsUrl;
}

/**
* Returns the {@link String} representation of this aesgcm URL.
*
* @return aesgcm URL with key and IV.
*/
public String getAesgcmUrl() {
String aesgcmUrl = httpsUrl.toString().replaceFirst(httpsUrl.getProtocol(), PROTOCOL);
return aesgcmUrl + "#" + StringUtils.encodeHex(ivBytes) + StringUtils.encodeHex(keyBytes);
}

/**
* Returns a {@link Cipher} in decryption mode, which can be used to decrypt the offered file.
*
* @return cipher
*
* @throws NoSuchPaddingException if the JVM cannot provide the specified cipher mode
* @throws NoSuchAlgorithmException if the JVM cannot provide the specified cipher mode
* @throws InvalidAlgorithmParameterException if the JVM cannot provide the specified cipher
* (eg. if no BC provider is added)
* @throws InvalidKeyException if the provided key is invalid
*/
public Cipher getDecryptionCipher() throws NoSuchPaddingException, NoSuchAlgorithmException,
InvalidAlgorithmParameterException, InvalidKeyException {
return OmemoMediaSharingUtils.decryptionCipherFrom(keyBytes, ivBytes);
}

private static URL extractHttpsUrl(String aesgcmUrlString) {
// aesgcm -> https
String httpsUrlString = aesgcmUrlString.replaceFirst(PROTOCOL, "https");
// remove #ref
httpsUrlString = httpsUrlString.substring(0, httpsUrlString.indexOf("#"));

try {
return new URL(httpsUrlString);
} catch (MalformedURLException e) {
throw new AssertionError("Failed to convert aesgcm URL to https URL: '" + aesgcmUrlString + "'", e);
}
}

private static byte[][] extractIVAndKey(String aesgcmUrlString) {
int startOfRef = aesgcmUrlString.lastIndexOf("#");
if (startOfRef == -1) {
throw new IllegalArgumentException("The provided aesgcm Url does not have a ref part which is " +
"supposed to contain the encryption key for file encryption.");
}

String ref = aesgcmUrlString.substring(startOfRef + 1);
byte[] refBytes = StringUtils.hexStringToByteArray(ref);

byte[] key = new byte[32];
byte[] iv;
int ivLen;
// determine the length of the initialization vector part
switch (refBytes.length) {
// 32 bytes key + 16 bytes IV
case 48:
ivLen = 16;
break;

// 32 bytes key + 12 bytes IV
case 44:
ivLen = 12;
break;
default:
throw new IllegalArgumentException("Provided URL has an invalid ref tag (" + ref.length() + "): '" + ref + "'");
}
iv = new byte[ivLen];
System.arraycopy(refBytes, 0, iv, 0, ivLen);
System.arraycopy(refBytes, ivLen, key, 0, 32);

return new byte[][] {iv,key};
}
}
}
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