From 0676688c04e6c00ab1472bb48c6d77a1a2b8dbeb Mon Sep 17 00:00:00 2001
From: vanitasvitae <vanitasvitae@fsfe.org>
Date: Sun, 20 Aug 2017 14:59:32 +0200
Subject: [PATCH] Consider file of hash when deciding to accept file

---
 .../de/vanitasvitae/sync_client/Master.java   | 13 +++++++++-
 .../de/vanitasvitae/sync_client/Slave.java    | 26 ++++++++++++++-----
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/src/main/java/de/vanitasvitae/sync_client/Master.java b/src/main/java/de/vanitasvitae/sync_client/Master.java
index 5fdada6..315c0ce 100644
--- a/src/main/java/de/vanitasvitae/sync_client/Master.java
+++ b/src/main/java/de/vanitasvitae/sync_client/Master.java
@@ -31,8 +31,10 @@ import javax.crypto.NoSuchPaddingException;
 import org.jivesoftware.smack.SmackException;
 import org.jivesoftware.smack.XMPPException;
 import org.jivesoftware.smack.util.Async;
+import org.jivesoftware.smackx.hashes.HashManager;
 import org.jivesoftware.smackx.jet.JetManager;
 import org.jivesoftware.smackx.jingle_filetransfer.JingleFileTransferManager;
+import org.jivesoftware.smackx.jingle_filetransfer.component.JingleFile;
 import org.jivesoftware.smackx.omemo.OmemoManager;
 import org.jivesoftware.smackx.omemo.exceptions.CorruptedOmemoKeyException;
 
@@ -201,8 +203,17 @@ public class Master extends Client {
             throw new AssertionError("Illegal path! " + fileName);
         }
 
+        JingleFile metadata = null;
+
         try {
-            jetm.sendEncryptedFile(file, fileName, remote, OmemoManager.getInstanceFor(connection));
+            metadata = JingleFile.fromFile(file, null, null, HashManager.ALGORITHM.SHA_256);
+            metadata.setName(fileName);
+        } catch (NoSuchAlgorithmException | IOException e) {
+            System.out.println("Could not calculate hash: " + e);
+        }
+
+        try {
+            jetm.sendEncryptedFile(file, metadata, remote, OmemoManager.getInstanceFor(connection));
         } catch (Exception e) {
             System.out.println("Could not send file: " + e);
         }
diff --git a/src/main/java/de/vanitasvitae/sync_client/Slave.java b/src/main/java/de/vanitasvitae/sync_client/Slave.java
index e826a8d..fe9fd47 100644
--- a/src/main/java/de/vanitasvitae/sync_client/Slave.java
+++ b/src/main/java/de/vanitasvitae/sync_client/Slave.java
@@ -7,14 +7,16 @@ import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.security.NoSuchProviderException;
-import java.util.logging.Logger;
+import java.util.Arrays;
 import javax.crypto.BadPaddingException;
 import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.NoSuchPaddingException;
 
 import org.jivesoftware.smack.SmackException;
 import org.jivesoftware.smack.XMPPException;
+import org.jivesoftware.smackx.hashes.element.HashElement;
 import org.jivesoftware.smackx.jingle_filetransfer.JingleFileTransferManager;
+import org.jivesoftware.smackx.jingle_filetransfer.component.JingleFile;
 import org.jivesoftware.smackx.omemo.exceptions.CorruptedOmemoKeyException;
 
 import org.jxmpp.stringprep.XmppStringprepException;
@@ -30,12 +32,24 @@ public class Slave extends Client {
         JingleFileTransferManager jingleFileTransferManager = JingleFileTransferManager.getInstanceFor(connection);
         jingleFileTransferManager.addIncomingFileOfferListener(offer -> {
             try {
-                File target = new File(root.toFile(), offer.getFile().getName());
-                if (target.exists() && target.length() == offer.getFile().getSize()) {
-                    System.out.println("We already seem to have file " + target.getAbsolutePath()+ ". Cancel.");
-                    offer.cancel(connection);
-                    return;
+                File target = new File(root.toFile(), offer.getMetadata().getName());
+                if (target.exists() && target.length() == offer.getMetadata().getSize()) {
+
+                    if (offer.getMetadata().getHashElement() != null) {
+                        HashElement offerHash = offer.getMetadata().getHashElement();
+                        try {
+                            HashElement ourHash = JingleFile.calculateHash(target, offerHash.getAlgorithm());
+                            if (Arrays.equals(ourHash.getHash(), offerHash.getHash())) {
+                                System.out.println("We already seem to have file " + target.getAbsolutePath()+ ". Cancel.");
+                                offer.cancel(connection);
+                                return;
+                            }
+                        } catch (NoSuchAlgorithmException e) {
+                            System.out.println("Unsupported hash algo: " + e);
+                        }
+                    }
                 }
+                
                 target.getParentFile().mkdirs();
                 offer.accept(connection, target);
             } catch (InterruptedException | XMPPException.XMPPErrorException | SmackException.NoResponseException | SmackException.NotConnectedException | IOException e) {