From e3f396ccd85c0f01eecfc3e8630026b0e20ccd39 Mon Sep 17 00:00:00 2001
From: manuroe <manu@matrix.org>
Date: Wed, 29 Sep 2021 22:02:19 +0100
Subject: [PATCH] AppDelegate: Fix a crash when backgrounding the app

By avoiding to call [MXCrossSigning refreshStateWithSuccess]  because it leads to a crash in Realm.
---
 Riot/Modules/Application/LegacyAppDelegate.m | 69 ++++++++++++--------
 changelog.d/4932.bugfix                      |  1 +
 2 files changed, 44 insertions(+), 26 deletions(-)
 create mode 100644 changelog.d/4932.bugfix

diff --git a/Riot/Modules/Application/LegacyAppDelegate.m b/Riot/Modules/Application/LegacyAppDelegate.m
index 1ad7847f8..bce8e618d 100644
--- a/Riot/Modules/Application/LegacyAppDelegate.m
+++ b/Riot/Modules/Application/LegacyAppDelegate.m
@@ -2264,6 +2264,7 @@ NSString *const AppDelegateUniversalLinkDidChangeNotification = @"AppDelegateUni
         }
         else
         {
+            MXLogDebug(@"[AppDelegate] handleAppState: mainSession.state: %@", [MXTools readableSessionState:mainSession.state]);
             switch (mainSession.state)
             {
                 case MXSessionStateClosed:
@@ -2316,32 +2317,8 @@ NSString *const AppDelegateUniversalLinkDidChangeNotification = @"AppDelegateUni
                 return;
             }
             
-            if (mainSession.crypto.crossSigning)
-            {
-                // Get the up-to-date cross-signing state
-                MXWeakify(self);
-                [mainSession.crypto.crossSigning refreshStateWithSuccess:^(BOOL stateUpdated) {
-                    MXStrongifyAndReturnIfNil(self);
-                    
-                    MXLogDebug(@"[AppDelegate] handleAppState: crossSigning.state: %@", @(mainSession.crypto.crossSigning.state));
-                    
-                    switch (mainSession.crypto.crossSigning.state)
-                    {
-                        case MXCrossSigningStateCrossSigningExists:
-                            MXLogDebug(@"[AppDelegate] handleAppState: presentVerifyCurrentSessionAlertIfNeededWithSession");
-                            [self.masterTabBarController presentVerifyCurrentSessionAlertIfNeededWithSession:mainSession];
-                            break;
-                        case MXCrossSigningStateCanCrossSign:
-                            MXLogDebug(@"[AppDelegate] handleAppState: presentReviewUnverifiedSessionsAlertIfNeededWithSession");
-                            [self.masterTabBarController presentReviewUnverifiedSessionsAlertIfNeededWithSession:mainSession];
-                            break;
-                        default:
-                            break;
-                    }
-                } failure:^(NSError * _Nonnull error) {
-                    MXLogDebug(@"[AppDelegate] handleAppState: crossSigning.state: %@. Error: %@", @(mainSession.crypto.crossSigning.state), error);
-                }];
-            }
+            MXLogDebug(@"[AppDelegate] handleAppState: Check cross-signing");
+            [self checkCrossSigningForSession:mainSession];
             
             // TODO: We should wait that cross-signing screens are done before going further but it seems fine. Those screens
             // protect each other.
@@ -3311,6 +3288,46 @@ NSString *const AppDelegateUniversalLinkDidChangeNotification = @"AppDelegateUni
     [callEventsListeners removeObjectForKey:@(mxSession.hash)];
 }
 
+
+#pragma mark - Cross-signing
+
+- (void)checkCrossSigningForSession:(MXSession*)mxSession
+{
+    if ([UIApplication sharedApplication].applicationState != UIApplicationStateActive)
+    {
+        MXLogDebug(@"[AppDelegate] checkCrossSigningForSession called while the app is not active. Ignore it.");
+        return;
+    }
+    
+    if (mxSession.crypto.crossSigning)
+    {
+        // Get the up-to-date cross-signing state
+        MXWeakify(self);
+        [mxSession.crypto.crossSigning refreshStateWithSuccess:^(BOOL stateUpdated) {
+            MXStrongifyAndReturnIfNil(self);
+            
+            MXLogDebug(@"[AppDelegate] handleAppState: crossSigning.state: %@", @(mxSession.crypto.crossSigning.state));
+            
+            switch (mxSession.crypto.crossSigning.state)
+            {
+                case MXCrossSigningStateCrossSigningExists:
+                    MXLogDebug(@"[AppDelegate] handleAppState: presentVerifyCurrentSessionAlertIfNeededWithSession");
+                    [self.masterTabBarController presentVerifyCurrentSessionAlertIfNeededWithSession:mxSession];
+                    break;
+                case MXCrossSigningStateCanCrossSign:
+                    MXLogDebug(@"[AppDelegate] handleAppState: presentReviewUnverifiedSessionsAlertIfNeededWithSession");
+                    [self.masterTabBarController presentReviewUnverifiedSessionsAlertIfNeededWithSession:mxSession];
+                    break;
+                default:
+                    break;
+            }
+        } failure:^(NSError * _Nonnull error) {
+            MXLogDebug(@"[AppDelegate] handleAppState: crossSigning.state: %@. Error: %@", @(mxSession.crypto.crossSigning.state), error);
+        }];
+    }
+}
+
+
 #pragma mark - Incoming room key requests handling
 
 - (void)enableRoomKeyRequestObserver:(MXSession*)mxSession
diff --git a/changelog.d/4932.bugfix b/changelog.d/4932.bugfix
new file mode 100644
index 000000000..5a4292a01
--- /dev/null
+++ b/changelog.d/4932.bugfix
@@ -0,0 +1 @@
+AppDelegate: Fix a crash when backgrounding the app.
\ No newline at end of file