From a33984acc5b0431d24bc965b99d1bb44ff7073a7 Mon Sep 17 00:00:00 2001
From: Daniel Gultsch <daniel@gultsch.de>
Date: Sat, 27 Jan 2018 20:55:43 +0100
Subject: [PATCH] encrypt muc PM only to actual recipient

---
 .../crypto/axolotl/AxolotlService.java        | 29 +++++++++++++++----
 .../ui/ConversationFragment.java              |  6 ++--
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
index 701155e10..1eb4b4a03 100644
--- a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
+++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
@@ -1234,6 +1234,23 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 		return true;
 	}
 
+	//this is being used for private muc messages only
+	private boolean buildHeader(XmppAxolotlMessage axolotlMessage, Jid jid) {
+		if (jid == null) {
+			return false;
+		}
+		HashSet<XmppAxolotlSession> sessions = new HashSet<>();
+		sessions.addAll(this.sessions.getAll(getAddressForJid(jid).getName()).values());
+		if (sessions.isEmpty()) {
+			return false;
+		}
+		sessions.addAll(findOwnSessions());
+		for(XmppAxolotlSession session : sessions) {
+			axolotlMessage.addDevice(session);
+		}
+		return true;
+	}
+
 	@Nullable
 	public XmppAxolotlMessage encrypt(Message message) {
 		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(account.getJid().toBareJid(), getOwnDeviceId());
@@ -1249,12 +1266,14 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
 			return null;
 		}
-		//TODO: fix this for MUC PMs - Don't encrypt to all participants
-		if (!buildHeader(axolotlMessage, message.getConversation())) {
-			return null;
-		}
 
-		return axolotlMessage;
+		final boolean success;
+		if (message.getType() == Message.TYPE_PRIVATE) {
+			success = buildHeader(axolotlMessage, message.getTrueCounterpart());
+		} else {
+			success = buildHeader(axolotlMessage, message.getConversation());
+		}
+		return success ? axolotlMessage : null;
 	}
 
 	public void preparePayloadMessage(final Message message, final boolean delay) {
diff --git a/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java b/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
index 944fdeee3..d7b6ea8a5 100644
--- a/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
+++ b/src/main/java/eu/siacs/conversations/ui/ConversationFragment.java
@@ -469,8 +469,10 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 		if (conversation.getCorrectingMessage() == null) {
 			message = new Message(conversation, body, conversation.getNextEncryption());
 			if (conversation.getMode() == Conversation.MODE_MULTI) {
-				if (conversation.getNextCounterpart() != null) {
-					message.setCounterpart(conversation.getNextCounterpart());
+				final Jid nextCounterpart = conversation.getNextCounterpart();
+				if (nextCounterpart != null) {
+					message.setCounterpart(nextCounterpart);
+					message.setTrueCounterpart(conversation.getMucOptions().getTrueCounterpart(nextCounterpart));
 					message.setType(Message.TYPE_PRIVATE);
 				}
 			}