Superclass for validating messages that are BDF lists.

2026-02-18 13:49:53 +01:00 · 2016-02-29 21:57:02 +00:00
parent 05ec49e45b
commit cc7ffee28d
8 changed files with 290 additions and 322 deletions
--- a/briar-core/src/org/briarproject/clients/BdfMessageValidator.java
+++ b/briar-core/src/org/briarproject/clients/BdfMessageValidator.java
@@ -0,0 +1,114 @@
+package org.briarproject.clients;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.data.BdfDictionary;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.data.MetadataEncoder;
+import org.briarproject.api.db.Metadata;
+import org.briarproject.api.sync.Group;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageValidator;
+import org.briarproject.api.system.Clock;
+import org.briarproject.util.StringUtils;
+
+import java.util.logging.Logger;
+
+import static org.briarproject.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.api.transport.TransportConstants.MAX_CLOCK_DIFFERENCE;
+
+public abstract class BdfMessageValidator implements MessageValidator {
+
+	protected static final Logger LOG =
+			Logger.getLogger(BdfMessageValidator.class.getName());
+
+	protected final ClientHelper clientHelper;
+	protected final MetadataEncoder metadataEncoder;
+	protected final Clock clock;
+
+	protected BdfMessageValidator(ClientHelper clientHelper,
+			MetadataEncoder metadataEncoder, Clock clock) {
+		this.clientHelper = clientHelper;
+		this.metadataEncoder = metadataEncoder;
+		this.clock = clock;
+	}
+
+	protected abstract BdfDictionary validateMessage(BdfList message, Group g,
+			long timestamp) throws FormatException;
+
+	@Override
+	public Metadata validateMessage(Message m, Group g) {
+		// Reject the message if it's too far in the future
+		long now = clock.currentTimeMillis();
+		if (m.getTimestamp() - now > MAX_CLOCK_DIFFERENCE) {
+			LOG.info("Timestamp is too far in the future");
+			return null;
+		}
+		byte[] raw = m.getRaw();
+		try {
+			BdfList message = clientHelper.toList(raw, MESSAGE_HEADER_LENGTH,
+					raw.length - MESSAGE_HEADER_LENGTH);
+			BdfDictionary meta = validateMessage(message, g, m.getTimestamp());
+			if (meta == null) {
+				LOG.info("Invalid message");
+				return null;
+			}
+			return metadataEncoder.encode(meta);
+		} catch (FormatException e) {
+			LOG.info("Invalid message");
+			return null;
+		}
+	}
+
+	protected void checkLength(String s, int minLength, int maxLength)
+			throws FormatException {
+		if (s != null) {
+			int length = StringUtils.toUtf8(s).length;
+			if (length < minLength) throw new FormatException();
+			if (length > maxLength) throw new FormatException();
+		}
+	}
+
+	protected void checkLength(String s, int length) throws FormatException {
+		if (s != null && StringUtils.toUtf8(s).length != length)
+			throw new FormatException();
+	}
+
+	protected void checkLength(byte[] b, int minLength, int maxLength)
+			throws FormatException {
+		if (b != null) {
+			if (b.length < minLength) throw new FormatException();
+			if (b.length > maxLength) throw new FormatException();
+		}
+	}
+
+	protected void checkLength(byte[] b, int length) throws FormatException {
+		if (b != null && b.length != length) throw new FormatException();
+	}
+
+	protected void checkSize(BdfList list, int minSize, int maxSize)
+		throws FormatException {
+		if (list != null) {
+			if (list.size() < minSize) throw new FormatException();
+			if (list.size() > maxSize) throw new FormatException();
+		}
+	}
+
+	protected void checkSize(BdfList list, int size) throws FormatException {
+		if (list != null && list.size() != size) throw new FormatException();
+	}
+
+	protected void checkSize(BdfDictionary dictionary, int minSize,
+			int maxSize) throws FormatException {
+		if (dictionary != null) {
+			if (dictionary.size() < minSize) throw new FormatException();
+			if (dictionary.size() > maxSize) throw new FormatException();
+		}
+	}
+
+	protected void checkSize(BdfDictionary dictionary, int size)
+			throws FormatException {
+		if (dictionary != null && dictionary.size() != size)
+			throw new FormatException();
+	}
+}