From efcefc2e6301f6255ebcb3e11f0f0a51731bacca Mon Sep 17 00:00:00 2001
From: Andreas Straub <andy@strb.org>
Date: Tue, 28 Jul 2015 22:00:54 +0200
Subject: Refactor out inner classes, cache trust store

Moves SQLiteAxolotlStore and XmppAxolotlSession into proper classes.

IdentityKeys trust statuses are now cached in an LruCache to prevent
hammering the database when rendering the UI.
---
 .../crypto/axolotl/XmppAxolotlSession.java         | 131 +++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java

(limited to 'src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java')

diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java
new file mode 100644
index 00000000..b8d7dcba
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java
@@ -0,0 +1,131 @@
+package eu.siacs.conversations.crypto.axolotl;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.util.Log;
+
+import org.whispersystems.libaxolotl.AxolotlAddress;
+import org.whispersystems.libaxolotl.DuplicateMessageException;
+import org.whispersystems.libaxolotl.InvalidKeyException;
+import org.whispersystems.libaxolotl.InvalidKeyIdException;
+import org.whispersystems.libaxolotl.InvalidMessageException;
+import org.whispersystems.libaxolotl.InvalidVersionException;
+import org.whispersystems.libaxolotl.LegacyMessageException;
+import org.whispersystems.libaxolotl.NoSessionException;
+import org.whispersystems.libaxolotl.SessionCipher;
+import org.whispersystems.libaxolotl.UntrustedIdentityException;
+import org.whispersystems.libaxolotl.protocol.CiphertextMessage;
+import org.whispersystems.libaxolotl.protocol.PreKeyWhisperMessage;
+import org.whispersystems.libaxolotl.protocol.WhisperMessage;
+
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.entities.Account;
+
+public class XmppAxolotlSession {
+	private final SessionCipher cipher;
+	private Integer preKeyId = null;
+	private final SQLiteAxolotlStore sqLiteAxolotlStore;
+
+	public AxolotlAddress getRemoteAddress() {
+		return remoteAddress;
+	}
+
+	private final AxolotlAddress remoteAddress;
+	private final Account account;
+	private String fingerprint = null;
+
+	public XmppAxolotlSession(Account account, SQLiteAxolotlStore store, AxolotlAddress remoteAddress, String fingerprint) {
+		this(account, store, remoteAddress);
+		this.fingerprint = fingerprint;
+	}
+
+	public XmppAxolotlSession(Account account, SQLiteAxolotlStore store, AxolotlAddress remoteAddress) {
+		this.cipher = new SessionCipher(store, remoteAddress);
+		this.remoteAddress = remoteAddress;
+		this.sqLiteAxolotlStore = store;
+		this.account = account;
+	}
+
+	public Integer getPreKeyId() {
+		return preKeyId;
+	}
+
+	public void resetPreKeyId() {
+
+		preKeyId = null;
+	}
+
+	public String getFingerprint() {
+		return fingerprint;
+	}
+
+	protected void setTrust(SQLiteAxolotlStore.Trust trust) {
+		sqLiteAxolotlStore.setFingerprintTrust(fingerprint, trust);
+	}
+
+	protected SQLiteAxolotlStore.Trust getTrust() {
+		return sqLiteAxolotlStore.getFingerprintTrust(fingerprint);
+	}
+
+	@Nullable
+	public byte[] processReceiving(XmppAxolotlMessage.XmppAxolotlMessageHeader incomingHeader) {
+		byte[] plaintext = null;
+		SQLiteAxolotlStore.Trust trust = getTrust();
+		switch (trust) {
+			case INACTIVE:
+			case UNDECIDED:
+			case UNTRUSTED:
+			case TRUSTED:
+				try {
+					try {
+						PreKeyWhisperMessage message = new PreKeyWhisperMessage(incomingHeader.getContents());
+						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)) {
+							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Had session with fingerprint " + this.fingerprint + ", received message with fingerprint " + fingerprint);
+						} else {
+							this.fingerprint = fingerprint;
+							plaintext = cipher.decrypt(message);
+							if (message.getPreKeyId().isPresent()) {
+								preKeyId = message.getPreKeyId().get();
+							}
+						}
+					} catch (InvalidMessageException | InvalidVersionException e) {
+						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "WhisperMessage received");
+						WhisperMessage message = new WhisperMessage(incomingHeader.getContents());
+						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());
+					}
+				} catch (LegacyMessageException | InvalidMessageException | DuplicateMessageException | NoSessionException e) {
+					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error decrypting axolotl header, " + e.getClass().getName() + ": " + e.getMessage());
+				}
+
+				if (plaintext != null && trust == SQLiteAxolotlStore.Trust.INACTIVE) {
+					setTrust(SQLiteAxolotlStore.Trust.TRUSTED);
+				}
+
+				break;
+
+			case COMPROMISED:
+			default:
+				// ignore
+				break;
+		}
+		return plaintext;
+	}
+
+	@Nullable
+	public XmppAxolotlMessage.XmppAxolotlMessageHeader processSending(@NonNull byte[] outgoingMessage) {
+		SQLiteAxolotlStore.Trust trust = getTrust();
+		if (trust == SQLiteAxolotlStore.Trust.TRUSTED) {
+			CiphertextMessage ciphertextMessage = cipher.encrypt(outgoingMessage);
+			XmppAxolotlMessage.XmppAxolotlMessageHeader header =
+					new XmppAxolotlMessage.XmppAxolotlMessageHeader(remoteAddress.getDeviceId(),
+							ciphertextMessage.serialize());
+			return header;
+		} else {
+			return null;
+		}
+	}
+}
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