From 005e7d5207f8ed9bea3486d0b74a1f4cc40c3a44 Mon Sep 17 00:00:00 2001
From: akwizgran <akwizgran@users.sourceforge.net>
Date: Tue, 13 Sep 2011 17:56:44 +0100
Subject: [PATCH] Added a random salt to prevent ID clashes between anonymous
messages.
---
api/net/sf/briar/api/crypto/CryptoComponent.java | 3 +++
api/net/sf/briar/api/protocol/Message.java | 3 +++
components/net/sf/briar/crypto/CryptoComponentImpl.java | 6 ++++++
components/net/sf/briar/db/DatabaseComponentImpl.java | 5 +++--
components/net/sf/briar/protocol/MessageEncoderImpl.java | 6 ++++++
components/net/sf/briar/protocol/MessageReader.java | 3 +++
6 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/api/net/sf/briar/api/crypto/CryptoComponent.java b/api/net/sf/briar/api/crypto/CryptoComponent.java
index 6997072e54..6b98dfad89 100644
--- a/api/net/sf/briar/api/crypto/CryptoComponent.java
+++ b/api/net/sf/briar/api/crypto/CryptoComponent.java
@@ -2,6 +2,7 @@ package net.sf.briar.api.crypto;
import java.security.KeyPair;
import java.security.MessageDigest;
+import java.security.SecureRandom;
import java.security.Signature;
import javax.crypto.Cipher;
@@ -36,5 +37,7 @@ public interface CryptoComponent {
MessageDigest getMessageDigest();
+ SecureRandom getSecureRandom();
+
Signature getSignature();
}
diff --git a/api/net/sf/briar/api/protocol/Message.java b/api/net/sf/briar/api/protocol/Message.java
index 252c73caa2..5af513d283 100644
--- a/api/net/sf/briar/api/protocol/Message.java
+++ b/api/net/sf/briar/api/protocol/Message.java
@@ -13,6 +13,9 @@ public interface Message {
/** The maximum length of a signature in bytes. */
static final int MAX_SIGNATURE_LENGTH = 100;
+ /** The length of the random salt in bytes. */
+ static final int SALT_LENGTH = 8;
+
/** Returns the message's unique identifier. */
MessageId getId();
diff --git a/components/net/sf/briar/crypto/CryptoComponentImpl.java b/components/net/sf/briar/crypto/CryptoComponentImpl.java
index 57ac876e58..352182701a 100644
--- a/components/net/sf/briar/crypto/CryptoComponentImpl.java
+++ b/components/net/sf/briar/crypto/CryptoComponentImpl.java
@@ -8,6 +8,7 @@ import java.security.KeyPairGenerator;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
+import java.security.SecureRandom;
import java.security.Security;
import java.security.Signature;
import java.util.Arrays;
@@ -205,6 +206,11 @@ class CryptoComponentImpl implements CryptoComponent {
}
}
+ public SecureRandom getSecureRandom() {
+ // FIXME: Implement a PRNG (pony/rainbow/nyancat generator)
+ return new SecureRandom();
+ }
+
public Signature getSignature() {
try {
return Signature.getInstance(SIGNATURE_ALGO, PROVIDER);
diff --git a/components/net/sf/briar/db/DatabaseComponentImpl.java b/components/net/sf/briar/db/DatabaseComponentImpl.java
index 55ca48a4bf..5ecded11a1 100644
--- a/components/net/sf/briar/db/DatabaseComponentImpl.java
+++ b/components/net/sf/briar/db/DatabaseComponentImpl.java
@@ -178,7 +178,7 @@ DatabaseCleaner.Callback {
*/
protected boolean storeGroupMessage(Txn txn, Message m, ContactId sender)
throws DbException {
- if(m.getGroup() == null) throw new IllegalArgumentException();
+ assert m.getGroup() != null;
boolean stored = db.addGroupMessage(txn, m);
// Mark the message as seen by the sender
MessageId id = m.getId();
@@ -228,7 +228,8 @@ DatabaseCleaner.Callback {
*/
protected boolean storePrivateMessage(Txn txn, Message m, ContactId c,
boolean incoming) throws DbException {
- if(m.getGroup() != null) throw new IllegalArgumentException();
+ assert m.getGroup() == null;
+ assert m.getAuthor() == null;
if(!db.addPrivateMessage(txn, m, c)) return false;
MessageId id = m.getId();
if(incoming) db.setStatus(txn, c, id, Status.SEEN);
diff --git a/components/net/sf/briar/protocol/MessageEncoderImpl.java b/components/net/sf/briar/protocol/MessageEncoderImpl.java
index f36e94a222..1c3a386c3b 100644
--- a/components/net/sf/briar/protocol/MessageEncoderImpl.java
+++ b/components/net/sf/briar/protocol/MessageEncoderImpl.java
@@ -5,6 +5,7 @@ import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.security.PrivateKey;
+import java.security.SecureRandom;
import java.security.Signature;
import net.sf.briar.api.crypto.CryptoComponent;
@@ -23,12 +24,14 @@ import com.google.inject.Inject;
class MessageEncoderImpl implements MessageEncoder {
private final Signature signature;
+ private final SecureRandom random;
private final MessageDigest messageDigest;
private final WriterFactory writerFactory;
@Inject
MessageEncoderImpl(CryptoComponent crypto, WriterFactory writerFactory) {
signature = crypto.getSignature();
+ random = crypto.getSecureRandom();
messageDigest = crypto.getMessageDigest();
this.writerFactory = writerFactory;
}
@@ -79,6 +82,9 @@ class MessageEncoderImpl implements MessageEncoder {
if(author == null) w.writeNull();
else author.writeTo(w);
w.writeInt64(timestamp);
+ byte[] salt = new byte[Message.SALT_LENGTH];
+ random.nextBytes(salt);
+ w.writeBytes(salt);
w.writeBytes(body);
// Sign the message with the author's private key, if there is one
if(authorKey == null) {
diff --git a/components/net/sf/briar/protocol/MessageReader.java b/components/net/sf/briar/protocol/MessageReader.java
index cdcef062c9..30339c2453 100644
--- a/components/net/sf/briar/protocol/MessageReader.java
+++ b/components/net/sf/briar/protocol/MessageReader.java
@@ -79,6 +79,9 @@ class MessageReader implements ObjectReader<Message> {
// Read the timestamp
long timestamp = r.readInt64();
if(timestamp < 0L) throw new FormatException();
+ // Read the salt
+ byte[] salt = r.readBytes(Message.SALT_LENGTH);
+ if(salt.length != Message.SALT_LENGTH) throw new FormatException();
// Skip the message body
r.readBytes(Message.MAX_BODY_LENGTH);
// Record the length of the data covered by the author's signature
--
GitLab