partially improved logging for receiving omemo messages

src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java

@@ -1136,7 +1136,12 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage;
 
 		XmppAxolotlSession session = getReceivingSession(message);
+		try {
 			keyTransportMessage = message.getParameters(session, getOwnDeviceId());
+		} catch (CryptoFailedException e) {
+			Log.d(Config.LOGTAG,"could not decrypt keyTransport message "+e.getMessage());
+			keyTransportMessage = null;
+		}
 
 		if (session.isFresh() && keyTransportMessage != null) {
 			putFreshSession(session);

src/main/java/eu/siacs/conversations/crypto/axolotl/CryptoFailedException.java

@@ -1,6 +1,11 @@
 package eu.siacs.conversations.crypto.axolotl;
 
 public class CryptoFailedException extends Exception {
+
+	public CryptoFailedException(String msg) {
+		super(msg);
+	}
+
 	public CryptoFailedException(Exception e){
 		super(e);
 	}

src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java

@@ -250,16 +250,16 @@ public class XmppAxolotlMessage {
 		return encryptionElement;
 	}
 
-	private byte[] unpackKey(XmppAxolotlSession session, Integer sourceDeviceId) {
+	private byte[] unpackKey(XmppAxolotlSession session, Integer sourceDeviceId) throws CryptoFailedException {
 		XmppAxolotlSession.AxolotlKey encryptedKey = keys.get(sourceDeviceId);
-		return (encryptedKey != null) ? session.processReceiving(encryptedKey) : null;
+		if (encryptedKey == null) {
+			throw new CryptoFailedException("Message was not encrypted for this device");
+		}
+		return session.processReceiving(encryptedKey);
 	}
 
-	public XmppAxolotlKeyTransportMessage getParameters(XmppAxolotlSession session, Integer sourceDeviceId) {
+	public XmppAxolotlKeyTransportMessage getParameters(XmppAxolotlSession session, Integer sourceDeviceId) throws CryptoFailedException {
-		byte[] key = unpackKey(session, sourceDeviceId);
+		return new XmppAxolotlKeyTransportMessage(session.getFingerprint(), unpackKey(session, sourceDeviceId), getIV());
-		return (key != null)
-				? new XmppAxolotlKeyTransportMessage(session.getFingerprint(), key, getIV())
-				: null;
 	}
 
 	public XmppAxolotlPlaintextMessage decrypt(XmppAxolotlSession session, Integer sourceDeviceId) throws CryptoFailedException {

src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlSession.java

@@ -82,7 +82,7 @@ public class XmppAxolotlSession implements Comparable<XmppAxolotlSession> {
 	}
 
 	@Nullable
-	public byte[] processReceiving(AxolotlKey encryptedKey) {
+	public byte[] processReceiving(AxolotlKey encryptedKey) throws CryptoFailedException {
 		byte[] plaintext = null;
 		FingerprintStatus status = getTrust();
 		if (!status.isCompromised()) {
@@ -90,8 +90,7 @@ public class XmppAxolotlSession implements Comparable<XmppAxolotlSession> {
 				try {
 					PreKeyWhisperMessage message = new PreKeyWhisperMessage(encryptedKey.key);
 					if (!message.getPreKeyId().isPresent()) {
-						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "PreKeyWhisperMessage did not contain a PreKeyId");
+						throw new CryptoFailedException("PreKeyWhisperMessage did not contain a PreKeyId");
-						return null;
 					}
 					Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "PreKeyWhisperMessage received, new session ID:" + message.getSignedPreKeyId() + "/" + message.getPreKeyId());
 					IdentityKey msgIdentityKey = message.getIdentityKey();
@@ -107,19 +106,19 @@ public class XmppAxolotlSession implements Comparable<XmppAxolotlSession> {
 					WhisperMessage message = new WhisperMessage(encryptedKey.key);
 					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());
+					throw new CryptoFailedException("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());
+				throw new CryptoFailedException("Error decrypting axolotl header, \" + e.getClass().getName() + \": \" + e.getMessage()");
+			}
+			if (plaintext==null) {
+				throw new CryptoFailedException("plaintext unexpectedly null");
 			}
-
-			if (plaintext != null) {
 			if (!status.isActive()) {
 				setTrust(status.toActive());
 			}
-			}
 		} else {
-			Log.d(Config.LOGTAG,account.getJid().toBareJid()+" not encrypting omemo message from fingerprint "+getFingerprint()+" because it was marked as compromised");
+			throw new CryptoFailedException("not encrypting omemo message from fingerprint "+getFingerprint()+" because it was marked as compromised");
 		}
 		return plaintext;
 	}