From f9d7fd355c6354e81abaea1f8ca4f7f336997c53 Mon Sep 17 00:00:00 2001
From: Felix Schwarz <fs-git@iospirit.com>
Date: Wed, 28 Jul 2021 11:42:05 +0200
Subject: [PATCH] Add safeguards against mutation of OCCore._queries during
 enumeration.

---
 .../OCCore+ConnectionStatus.m                 |  8 +++++++-
 ownCloudSDK/Core/ItemList/OCCore+ItemList.m   |  9 ++++++++-
 ownCloudSDK/Core/OCCore+ItemUpdates.m         |  8 +++++++-
 ownCloudSDK/Core/OCCore.m                     | 19 ++++++++++++++++---
 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/ownCloudSDK/Core/Connection Status/OCCore+ConnectionStatus.m b/ownCloudSDK/Core/Connection Status/OCCore+ConnectionStatus.m
index 92c1856c..0781105c 100644
--- a/ownCloudSDK/Core/Connection Status/OCCore+ConnectionStatus.m	
+++ b/ownCloudSDK/Core/Connection Status/OCCore+ConnectionStatus.m	
@@ -328,7 +328,13 @@ - (void)updateConnectionStatus:(OCCoreConnectionStatus)newStatus withSignal:(OCC
 					[self queueBlock:^{ // See if we can proceed
 						if (self->_state == OCCoreStateRunning)
 						{
-							for (OCQuery *query in self->_queries)
+							NSArray *queries;
+							@synchronized(self->_queries)
+							{
+								queries = [self->_queries copy];
+							}
+
+							for (OCQuery *query in queries)
 							{
 								if (query.state == OCQueryStateContentsFromCache)
 								{
diff --git a/ownCloudSDK/Core/ItemList/OCCore+ItemList.m b/ownCloudSDK/Core/ItemList/OCCore+ItemList.m
index a13d2b70..6cd8ad4e 100644
--- a/ownCloudSDK/Core/ItemList/OCCore+ItemList.m
+++ b/ownCloudSDK/Core/ItemList/OCCore+ItemList.m
@@ -1025,7 +1025,14 @@ - (void)_finalizeQueryUpdatesWithQueryResults:(NSMutableArray<OCItem *> *)queryR
 	}
 
 	// Update queries
-	for (OCQuery *query in self->_queries)
+	NSArray *queries;
+
+	@synchronized(self->_queries)
+	{
+		queries = [self->_queries copy];
+	}
+
+	for (OCQuery *query in queries)
 	{
 		NSMutableArray <OCItem *> *useQueryResults = nil;
 		OCItem *queryRootItem = nil;
diff --git a/ownCloudSDK/Core/OCCore+ItemUpdates.m b/ownCloudSDK/Core/OCCore+ItemUpdates.m
index 26d645e0..86785767 100644
--- a/ownCloudSDK/Core/OCCore+ItemUpdates.m
+++ b/ownCloudSDK/Core/OCCore+ItemUpdates.m
@@ -223,7 +223,13 @@ - (void)performUpdatesForAddedItems:(nullable NSArray<OCItem *> *)addedItems
 				}
 			};
 
-			for (OCQuery *query in self->_queries)
+			NSArray *queries;
+			@synchronized(self->_queries)
+			{
+				queries = [self->_queries copy];
+			}
+
+			for (OCQuery *query in queries)
 			{
 				// Protect full query results against modification (-setFullQueryResults: is protected using @synchronized(query), too)
 				@synchronized(query)
diff --git a/ownCloudSDK/Core/OCCore.m b/ownCloudSDK/Core/OCCore.m
index 994fe856..dfcce5de 100644
--- a/ownCloudSDK/Core/OCCore.m
+++ b/ownCloudSDK/Core/OCCore.m
@@ -820,7 +820,10 @@ - (void)startQuery:(OCCoreQuery *)coreQuery
 	{
 		// Add query to list of queries
 		[self queueBlock:^{
-			[self->_queries addObject:query];
+			@synchronized(self->_queries)
+			{
+				[self->_queries addObject:query];
+			}
 		}];
 
 		if (!query.isCustom)
@@ -889,7 +892,10 @@ - (void)stopQuery:(OCCoreQuery *)coreQuery
 			[query.stopAction cancel];
 
 			query.state = OCQueryStateStopped;
-			[self->_queries removeObject:query];
+			@synchronized(self->_queries)
+			{
+				[self->_queries removeObject:query];
+			}
 		}];
 	}
 
@@ -1101,7 +1107,14 @@ - (void)_replayChangesSinceSyncAnchor:(OCSyncAnchor)fromSyncAnchor
 				newSyncAnchor:syncAnchor
 				beforeQueryUpdates:^(dispatch_block_t  _Nonnull completionHandler) {
 					// Find items that moved to a different path
-					for (OCQuery *query in self->_queries)
+					NSArray *queries;
+
+					@synchronized(self->_queries)
+					{
+						queries = [self->_queries copy];
+					}
+
+					for (OCQuery *query in queries)
 					{
 						OCCoreItemList *queryItemList;