Fix infinite IMDN loop by authorising clear IMDN and isComposing messages

src/chat/chat-message/chat-message-p.h

@@ -126,6 +126,9 @@ public:
 
 	void setEncryptionPrevented (bool value) { encryptionPrevented = value; }
 
+	void setAuthorisationWarning (bool value) { authorizationWarning = value; } // TODO find better name
+	bool getAuthorisationWarning () { return authorizationWarning; } // TODO find better name
+
 	// -----------------------------------------------------------------------------
 	// Deprecated methods only used for C wrapper, to be removed some day...
 	// -----------------------------------------------------------------------------
@@ -213,6 +216,7 @@ private:
 	IdentityAddress fromAddress;
 	IdentityAddress authenticatedFromAddress;
 	bool senderAuthenticationEnabled = true;
+	bool authorizationWarning = false; // TODO find a better name
 	IdentityAddress toAddress;
 
 	ChatMessage::State state = ChatMessage::State::Idle;

src/chat/chat-message/chat-message.cpp

@@ -533,6 +533,23 @@ LinphoneReason ChatMessagePrivate::receive () {
 		currentRecvStep |= ChatMessagePrivate::Step::Cpim;
 	}
 
+	// Message Authorisation (could be done in CPIM modifier)
+	// If LIMEv2 enabled, check authorisation warning flag
+	// If warning flag is true, check if message is an isComposing or an IMDN
+	if (q->getSharedFromThis()->getPrivate()->getAuthorisationWarning()) {
+		if (q->getSharedFromThis()->getInternalContent().getContentType() != ContentType::Imdn && q->getSharedFromThis()->getInternalContent().getContentType() != ContentType::ImIsComposing) {
+			// TODO acknowledge message reception with errorCode = 0
+			// TODO return a "message refused because not encrypted" IMDN to the sender
+			errorCode = 415; // TODO 415 for example, maybe another one is better ? 488 ? 603 ?
+			reason = linphone_error_code_to_reason(errorCode);
+			if (getNegativeDeliveryNotificationRequired()) {
+				static_cast<ChatRoomPrivate *>(q->getChatRoom()->getPrivate())->sendDeliveryErrorNotification(
+					q->getSharedFromThis(),
+					reason
+				);
+			}
+			return reason;
+		}
 	if ((currentRecvStep &ChatMessagePrivate::Step::Multipart) == ChatMessagePrivate::Step::Multipart) {
 		lInfo() << "Multipart step already done, skipping";
 	} else {

src/chat/encryption/lime-v2.cpp

@@ -280,10 +280,18 @@ ChatMessageModifier::Result LimeV2::processIncomingMessage (const shared_ptr<Cha
 	internalContent = message->getInternalContent();
 
 	// Check if message if encrypted and unwrap the multipart
+	ContentType incomingContentType = message->getInternalContent().getContentType();
 	ContentType expectedContentType = ContentType::Encrypted;
 	expectedContentType.addParameter("boundary", MultipartBoundary);
-	if (internalContent.getContentType() != expectedContentType) {
-		lError() << "LIMEv2 unexpected content-type: " << internalContent.getContentType();
+
+	if (incomingContentType == ContentType::Cpim) {
+		lInfo() << "LIMEv2 incoming CPIM message";
+		message->getPrivate()->setAuthorisationWarning(true);
+		// Disable sender authentication otherwise the message will always get discarded because it doesn't have a sipfrag
+		message->getPrivate()->enableSenderAuthentication(false);
+		return ChatMessageModifier::Result::Skipped;
+	} else if (incomingContentType != expectedContentType) {
+		lError() << "LIMEv2 unexpected content-type: " << incomingContentType;
 		return ChatMessageModifier::Result::Error;
 	}
 	list<Content> contentList = ContentManager::multipartToContentList(internalContent);