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Refactor axolotl message processing workflow

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XmppAxolotlMessage is now entirely responsible for handling encryption
and decryption of messages, only leveraging XmppAxolotlSession as a
packing/unpacking primitive for payload keys.

Removed pseudo-dead session generation code step from prepareMessage
function, as sessions have been created by invoking the
TrustKeysActivity for a while now.

Added prepareKeyTransportMessage function, which creates a message with
no payload. The key that is packed into the header keyElements can then
be used for other purposes (e.g. encrypted file transfer).
This commit is contained in:
Andreas Straub 2015-07-31 21:12:34 +02:00
parent 50b14434ee
commit 909f761ca1
7 changed files with 118 additions and 154 deletions
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113
src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
View file

@ -256,7 +256,7 @@ public class AxolotlService {
for (Integer deviceId : deviceIds) {
AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
if (sessions.get(ownDeviceAddress) == null) {
buildSessionFromPEP(null, ownDeviceAddress, false);
buildSessionFromPEP(ownDeviceAddress);
}
}
}
@ -422,7 +422,7 @@ public class AxolotlService {
axolotlStore.setFingerprintTrust(fingerprint, trust);
}
private void buildSessionFromPEP(final Conversation conversation, final AxolotlAddress address, final boolean flushWaitingQueueAfterFetch) {
private void buildSessionFromPEP(final AxolotlAddress address) {
Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new sesstion for " + address.getDeviceId());
try {
@ -434,15 +434,6 @@ public class AxolotlService {
AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
if (!fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
&& !fetchStatusMap.getAll(address).containsValue(FetchStatus.PENDING)) {
if (flushWaitingQueueAfterFetch && conversation != null) {
conversation.findUnsentMessagesWithEncryption(Message.ENCRYPTION_AXOLOTL,
new Conversation.OnMessageFound() {
@Override
public void onMessageFound(Message message) {
processSending(message, false);
}
});
}
mXmppConnectionService.keyStatusUpdated();
}
}
@ -537,7 +528,7 @@ public class AxolotlService {
return addresses;
}
public boolean createSessionsIfNeeded(final Conversation conversation, final boolean flushWaitingQueueAfterFetch) {
public boolean createSessionsIfNeeded(final Conversation conversation) {
Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
boolean newSessions = false;
Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
@ -546,7 +537,9 @@ public class AxolotlService {
FetchStatus status = fetchStatusMap.get(address);
if (status == null || status == FetchStatus.ERROR) {
fetchStatusMap.put(address, FetchStatus.PENDING);
this.buildSessionFromPEP(conversation, address, flushWaitingQueueAfterFetch);
this.buildSessionFromPEP(address);
newSessions = true;
} else if (status == FetchStatus.PENDING) {
newSessions = true;
} else {
Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
@ -565,40 +558,52 @@ public class AxolotlService {
}
@Nullable
public XmppAxolotlMessage encrypt(Message message) {
final String content;
if (message.hasFileOnRemoteHost()) {
content = message.getFileParams().url.toString();
} else {
content = message.getBody();
}
final XmppAxolotlMessage axolotlMessage;
try {
axolotlMessage = new XmppAxolotlMessage(message.getContact().getJid().toBareJid(),
getOwnDeviceId(), content);
} catch (CryptoFailedException e) {
Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
return null;
}
private XmppAxolotlMessage buildHeader(Contact contact) {
final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
contact.getJid().toBareJid(), getOwnDeviceId());
if (findSessionsforContact(message.getContact()).isEmpty()) {
Set<XmppAxolotlSession> contactSessions = findSessionsforContact(contact);
Set<XmppAxolotlSession> ownSessions = findOwnSessions();
if (contactSessions.isEmpty()) {
return null;
}
Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl foreign keyElements...");
for (XmppAxolotlSession session : findSessionsforContact(message.getContact())) {
for (XmppAxolotlSession session : contactSessions) {
Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
axolotlMessage.addKeyElement(session.processSending(axolotlMessage.getInnerKey()));
axolotlMessage.addDevice(session);
}
Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl own keyElements...");
for (XmppAxolotlSession session : findOwnSessions()) {
for (XmppAxolotlSession session : ownSessions) {
Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
axolotlMessage.addKeyElement(session.processSending(axolotlMessage.getInnerKey()));
axolotlMessage.addDevice(session);
}
return axolotlMessage;
}
private void processSending(final Message message, final boolean delay) {
@Nullable
public XmppAxolotlMessage encrypt(Message message) {
XmppAxolotlMessage axolotlMessage = buildHeader(message.getContact());
if (axolotlMessage != null) {
final String content;
if (message.hasFileOnRemoteHost()) {
content = message.getFileParams().url.toString();
} else {
content = message.getBody();
}
try {
axolotlMessage.encrypt(content);
} catch (CryptoFailedException e) {
Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
return null;
}
}
return axolotlMessage;
}
public void preparePayloadMessage(final Message message, final boolean delay) {
executor.execute(new Runnable() {
@Override
public void run() {
@ -615,13 +620,14 @@ public class AxolotlService {
});
}
public void prepareMessage(final Message message, final boolean delay) {
if (!messageCache.containsKey(message.getUuid())) {
boolean newSessions = createSessionsIfNeeded(message.getConversation(), true);
if (!newSessions) {
this.processSending(message, delay);
public void prepareKeyTransportMessage(final Contact contact, final OnMessageCreatedCallback onMessageCreatedCallback) {
executor.execute(new Runnable() {
@Override
public void run() {
XmppAxolotlMessage axolotlMessage = buildHeader(contact);
onMessageCreatedCallback.run(axolotlMessage);
}
}
});
}
public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
@ -653,26 +659,15 @@ public class AxolotlService {
newSession = true;
}
for (XmppAxolotlMessage.XmppAxolotlKeyElement keyElement : message.getKeyElements()) {
if (keyElement.getRecipientDeviceId() == getOwnDeviceId()) {
Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found axolotl keyElement matching own device ID, processing...");
byte[] payloadKey = session.processReceiving(keyElement);
if (payloadKey != null) {
Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got payload key from axolotl keyElement. Decrypting message...");
try {
plaintextMessage = message.decrypt(session, payloadKey, session.getFingerprint());
} catch (CryptoFailedException e) {
Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
break;
}
}
Integer preKeyId = session.getPreKeyId();
if (preKeyId != null) {
publishBundlesIfNeeded();
session.resetPreKeyId();
}
break;
try {
plaintextMessage = message.decrypt(session, getOwnDeviceId());
Integer preKeyId = session.getPreKeyId();
if (preKeyId != null) {
publishBundlesIfNeeded();
session.resetPreKeyId();
}
} catch (CryptoFailedException e) {
Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
}
if (newSession && plaintextMessage != null) {

136
src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java
View file

@ -1,6 +1,5 @@
package eu.siacs.conversations.crypto.axolotl;
import android.support.annotation.Nullable;
import android.util.Base64;
import android.util.Log;
@ -9,8 +8,9 @@ import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.util.HashSet;
import java.util.Set;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
@ -26,9 +26,11 @@ import eu.siacs.conversations.xml.Element;
import eu.siacs.conversations.xmpp.jid.Jid;
public class XmppAxolotlMessage {
public static final String TAGNAME = "encrypted";
public static final String CONTAINERTAG = "encrypted";
public static final String HEADER = "header";
public static final String SOURCEID = "sid";
public static final String KEYTAG = "key";
public static final String REMOTEID = "rid";
public static final String IVTAG = "iv";
public static final String PAYLOAD = "payload";
@ -39,54 +41,15 @@ public class XmppAxolotlMessage {
private byte[] innerKey;
private byte[] ciphertext = null;
private byte[] iv = null;
private final Set<XmppAxolotlKeyElement> keyElements;
private final Map<Integer, byte[]> keys;
private final Jid from;
private final int sourceDeviceId;
public static class XmppAxolotlKeyElement {
public static final String TAGNAME = "key";
public static final String REMOTEID = "rid";
private final int recipientDeviceId;
private final byte[] content;
public XmppAxolotlKeyElement(int deviceId, byte[] content) {
this.recipientDeviceId = deviceId;
this.content = content;
}
public XmppAxolotlKeyElement(Element keyElement) {
if (TAGNAME.equals(keyElement.getName())) {
this.recipientDeviceId = Integer.parseInt(keyElement.getAttribute(REMOTEID));
this.content = Base64.decode(keyElement.getContent(), Base64.DEFAULT);
} else {
throw new IllegalArgumentException("Argument not a <" + TAGNAME + "> Element!");
}
}
public int getRecipientDeviceId() {
return recipientDeviceId;
}
public byte[] getContents() {
return content;
}
public Element toXml() {
Element keyElement = new Element(TAGNAME);
keyElement.setAttribute(REMOTEID, getRecipientDeviceId());
keyElement.setContent(Base64.encodeToString(getContents(), Base64.DEFAULT));
return keyElement;
}
}
public static class XmppAxolotlPlaintextMessage {
private final XmppAxolotlSession session;
private final String plaintext;
private final String fingerprint;
public XmppAxolotlPlaintextMessage(XmppAxolotlSession session, String plaintext, String fingerprint) {
this.session = session;
public XmppAxolotlPlaintextMessage(String plaintext, String fingerprint) {
this.plaintext = plaintext;
this.fingerprint = fingerprint;
}
@ -95,24 +58,28 @@ public class XmppAxolotlMessage {
return plaintext;
}
public XmppAxolotlSession getSession() {
return session;
}
public String getFingerprint() {
return fingerprint;
}
}
public XmppAxolotlMessage(Jid from, Element axolotlMessage) throws IllegalArgumentException {
private XmppAxolotlMessage(final Element axolotlMessage, final Jid from) throws IllegalArgumentException {
this.from = from;
Element header = axolotlMessage.findChild(HEADER);
this.sourceDeviceId = Integer.parseInt(header.getAttribute(SOURCEID));
this.keyElements = new HashSet<>();
for (Element keyElement : header.getChildren()) {
List<Element> keyElements = header.getChildren();
this.keys = new HashMap<>(keyElements.size());
for (Element keyElement : keyElements) {
switch (keyElement.getName()) {
case XmppAxolotlKeyElement.TAGNAME:
keyElements.add(new XmppAxolotlKeyElement(keyElement));
case KEYTAG:
try {
Integer recipientId = Integer.parseInt(keyElement.getAttribute(REMOTEID));
byte[] key = Base64.decode(keyElement.getContent(), Base64.DEFAULT);
this.keys.put(recipientId, key);
} catch (NumberFormatException e) {
throw new IllegalArgumentException(e);
}
break;
case IVTAG:
if (this.iv != null) {
@ -134,14 +101,13 @@ public class XmppAxolotlMessage {
public XmppAxolotlMessage(Jid from, int sourceDeviceId) {
this.from = from;
this.sourceDeviceId = sourceDeviceId;
this.keyElements = new HashSet<>();
this.keys = new HashMap<>();
this.iv = generateIv();
this.innerKey = generateKey();
}
public XmppAxolotlMessage(Jid from, int sourceDeviceId, String plaintext) throws CryptoFailedException {
this(from, sourceDeviceId);
this.encrypt(plaintext);
public static XmppAxolotlMessage fromElement(Element element, Jid from) {
return new XmppAxolotlMessage(element, from);
}
private static byte[] generateKey() {
@ -162,7 +128,7 @@ public class XmppAxolotlMessage {
return iv;
}
private void encrypt(String plaintext) throws CryptoFailedException {
public void encrypt(String plaintext) throws CryptoFailedException {
try {
SecretKey secretKey = new SecretKeySpec(innerKey, KEYTYPE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
@ -189,13 +155,10 @@ public class XmppAxolotlMessage {
return ciphertext;
}
public Set<XmppAxolotlKeyElement> getKeyElements() {
return keyElements;
}
public void addKeyElement(@Nullable XmppAxolotlKeyElement keyElement) {
if (keyElement != null) {
keyElements.add(keyElement);
public void addDevice(XmppAxolotlSession session) {
byte[] key = session.processSending(innerKey);
if (key != null) {
keys.put(session.getRemoteAddress().getDeviceId(), key);
}
}
@ -207,12 +170,15 @@ public class XmppAxolotlMessage {
return this.iv;
}
public Element toXml() {
Element encryptionElement = new Element(TAGNAME, AxolotlService.PEP_PREFIX);
public Element toElement() {
Element encryptionElement = new Element(CONTAINERTAG, AxolotlService.PEP_PREFIX);
Element headerElement = encryptionElement.addChild(HEADER);
headerElement.setAttribute(SOURCEID, sourceDeviceId);
for (XmppAxolotlKeyElement header : keyElements) {
headerElement.addChild(header.toXml());
for (Map.Entry<Integer, byte[]> keyEntry : keys.entrySet()) {
Element keyElement = new Element(KEYTAG);
keyElement.setAttribute(REMOTEID, keyEntry.getKey());
keyElement.setContent(Base64.encodeToString(keyEntry.getValue(), Base64.DEFAULT));
headerElement.addChild(keyElement);
}
headerElement.addChild(IVTAG).setContent(Base64.encodeToString(iv, Base64.DEFAULT));
if (ciphertext != null) {
@ -222,24 +188,30 @@ public class XmppAxolotlMessage {
return encryptionElement;
}
public byte[] unpackKey(XmppAxolotlSession session, Integer sourceDeviceId) {
byte[] encryptedKey = keys.get(sourceDeviceId);
return (encryptedKey != null) ? session.processReceiving(encryptedKey) : null;
}
public XmppAxolotlPlaintextMessage decrypt(XmppAxolotlSession session, byte[] key, String fingerprint) throws CryptoFailedException {
public XmppAxolotlPlaintextMessage decrypt(XmppAxolotlSession session, Integer sourceDeviceId) throws CryptoFailedException {
XmppAxolotlPlaintextMessage plaintextMessage = null;
try {
byte[] key = unpackKey(session, sourceDeviceId);
if (key != null) {
try {
Cipher cipher = Cipher.getInstance(CIPHERMODE, PROVIDER);
SecretKeySpec keySpec = new SecretKeySpec(key, KEYTYPE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance(CIPHERMODE, PROVIDER);
SecretKeySpec keySpec = new SecretKeySpec(key, KEYTYPE);
IvParameterSpec ivSpec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
String plaintext = new String(cipher.doFinal(ciphertext));
plaintextMessage = new XmppAxolotlPlaintextMessage(plaintext, session.getFingerprint());
String plaintext = new String(cipher.doFinal(ciphertext));
plaintextMessage = new XmppAxolotlPlaintextMessage(session, plaintext, fingerprint);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException
| InvalidAlgorithmParameterException | IllegalBlockSizeException
| BadPaddingException | NoSuchProviderException e) {
throw new CryptoFailedException(e);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException
| InvalidAlgorithmParameterException | IllegalBlockSizeException
| BadPaddingException | NoSuchProviderException e) {
throw new CryptoFailedException(e);
}
}
return plaintextMessage;
}

13
src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java
View file

@ -69,7 +69,7 @@ public class XmppAxolotlSession {
}
@Nullable
public byte[] processReceiving(XmppAxolotlMessage.XmppAxolotlKeyElement incomingHeader) {
public byte[] processReceiving(byte[] encryptedKey) {
byte[] plaintext = null;
SQLiteAxolotlStore.Trust trust = getTrust();
switch (trust) {
@ -79,7 +79,7 @@ public class XmppAxolotlSession {
case TRUSTED:
try {
try {
PreKeyWhisperMessage message = new PreKeyWhisperMessage(incomingHeader.getContents());
PreKeyWhisperMessage message = new PreKeyWhisperMessage(encryptedKey);
Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "PreKeyWhisperMessage received, new session ID:" + message.getSignedPreKeyId() + "/" + message.getPreKeyId());
String fingerprint = message.getIdentityKey().getFingerprint().replaceAll("\\s", "");
if (this.fingerprint != null && !this.fingerprint.equals(fingerprint)) {
@ -93,7 +93,7 @@ public class XmppAxolotlSession {
}
} catch (InvalidMessageException | InvalidVersionException e) {
Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "WhisperMessage received");
WhisperMessage message = new WhisperMessage(incomingHeader.getContents());
WhisperMessage message = new WhisperMessage(encryptedKey);
plaintext = cipher.decrypt(message);
} catch (InvalidKeyException | InvalidKeyIdException | UntrustedIdentityException e) {
Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
@ -117,14 +117,11 @@ public class XmppAxolotlSession {
}
@Nullable
public XmppAxolotlMessage.XmppAxolotlKeyElement processSending(@NonNull byte[] outgoingMessage) {
public byte[] processSending(@NonNull byte[] outgoingMessage) {
SQLiteAxolotlStore.Trust trust = getTrust();
if (trust == SQLiteAxolotlStore.Trust.TRUSTED) {
CiphertextMessage ciphertextMessage = cipher.encrypt(outgoingMessage);
XmppAxolotlMessage.XmppAxolotlKeyElement header =
new XmppAxolotlMessage.XmppAxolotlKeyElement(remoteAddress.getDeviceId(),
ciphertextMessage.serialize());
return header;
return ciphertextMessage.serialize();
} else {
return null;
}

2
src/main/java/eu/siacs/conversations/generator/MessageGenerator.java
View file

@ -63,7 +63,7 @@ public class MessageGenerator extends AbstractGenerator {
if (axolotlMessage == null) {
return null;
}
packet.setAxolotlMessage(axolotlMessage.toXml());
packet.setAxolotlMessage(axolotlMessage.toElement());
return packet;
}

4
src/main/java/eu/siacs/conversations/parser/MessageParser.java
View file

@ -99,7 +99,7 @@ public class MessageParser extends AbstractParser implements
private Message parseAxolotlChat(Element axolotlMessage, Jid from, String id, Conversation conversation, int status) {
Message finishedMessage = null;
AxolotlService service = conversation.getAccount().getAxolotlService();
XmppAxolotlMessage xmppAxolotlMessage = new XmppAxolotlMessage(from.toBareJid(), axolotlMessage);
XmppAxolotlMessage xmppAxolotlMessage = XmppAxolotlMessage.fromElement(axolotlMessage, from.toBareJid());
XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = service.processReceiving(xmppAxolotlMessage);
if(plaintextMessage != null) {
finishedMessage = new Message(conversation, plaintextMessage.getPlaintext(), Message.ENCRYPTION_AXOLOTL, status);
@ -272,7 +272,7 @@ public class MessageParser extends AbstractParser implements
final String body = packet.getBody();
final Element mucUserElement = packet.findChild("x", "http://jabber.org/protocol/muc#user");
final String pgpEncrypted = packet.findChildContent("x", "jabber:x:encrypted");
final Element axolotlEncrypted = packet.findChild(XmppAxolotlMessage.TAGNAME, AxolotlService.PEP_PREFIX);
final Element axolotlEncrypted = packet.findChild(XmppAxolotlMessage.CONTAINERTAG, AxolotlService.PEP_PREFIX);
int status;
final Jid counterpart;
final Jid to = packet.getTo();

2
src/main/java/eu/siacs/conversations/services/XmppConnectionService.java
View file

@ -764,7 +764,7 @@ public class XmppConnectionService extends Service implements OnPhoneContactsLoa
} else {
XmppAxolotlMessage axolotlMessage = account.getAxolotlService().fetchAxolotlMessageFromCache(message);
if (axolotlMessage == null) {
account.getAxolotlService().prepareMessage(message,delay);
account.getAxolotlService().preparePayloadMessage(message, delay);
message.setAxolotlFingerprint(account.getAxolotlService().getOwnPublicKey().getFingerprint().replaceAll("\\s", ""));
} else {
packet = mMessageGenerator.generateAxolotlChat(message, axolotlMessage);

2
src/main/java/eu/siacs/conversations/ui/ConversationActivity.java
View file

@ -1265,7 +1265,7 @@ public class ConversationActivity extends XmppActivity
|| !axolotlService.findDevicesWithoutSession(mSelectedConversation).isEmpty();
boolean hasNoTrustedKeys = axolotlService.getNumTrustedKeys(mSelectedConversation.getContact()) == 0;
if( hasPendingKeys || hasNoTrustedKeys) {
axolotlService.createSessionsIfNeeded(mSelectedConversation, false);
axolotlService.createSessionsIfNeeded(mSelectedConversation);
Intent intent = new Intent(getApplicationContext(), TrustKeysActivity.class);
intent.putExtra("contact", mSelectedConversation.getContact().getJid().toBareJid().toString());
intent.putExtra("account", mSelectedConversation.getAccount().getJid().toBareJid().toString());