fix: Crash in CppException Monitor (#2639)

Only call the previous terminate_handler if it's not NULL to avoid crashing.

Fixes GH-1533

Co-authored-by: Andrew McKnight <andrew.mcknight@sentry.io>

Author: philipphofmann

CHANGELOG.md

@@ -12,6 +12,7 @@
 - Support uint64 in crash reports (#2631)
 - Always fetch view hierarchy on the main thread (#2629)
 - Carthage Xcode 14 compatibility issue (#2636)
+- Crash in CppException Monitor (#2639)
 
 ## 8.0.0
 

Sentry.xcodeproj/project.pbxproj

@@ -584,6 +584,7 @@
 		7BF9EF882722D13000B5BBEF /* SentryTestObjCRuntimeWrapper.m in Sources */ = {isa = PBXBuildFile; fileRef = 7BF9EF872722D13000B5BBEF /* SentryTestObjCRuntimeWrapper.m */; };
 		7BF9EF8B2722D58700B5BBEF /* SentryInitializeForGettingSubclassesNotCalled.m in Sources */ = {isa = PBXBuildFile; fileRef = 7BF9EF8A2722D58700B5BBEF /* SentryInitializeForGettingSubclassesNotCalled.m */; };
 		7BFA69F627E0840400233199 /* SentryANRTrackingIntegrationTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7BFA69F527E0840400233199 /* SentryANRTrackingIntegrationTests.swift */; };
+		7BFAA6E7297AA16A00E7E02E /* SentryCrashMonitor_CppException_Tests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 7BFAA6E6297AA16A00E7E02E /* SentryCrashMonitor_CppException_Tests.mm */; };
 		7BFC169B2524995700FF6266 /* SentryMessage.h in Headers */ = {isa = PBXBuildFile; fileRef = 7BFC169A2524995700FF6266 /* SentryMessage.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		7BFC16A125249A9D00FF6266 /* SentryMessage.m in Sources */ = {isa = PBXBuildFile; fileRef = 7BFC16A025249A9D00FF6266 /* SentryMessage.m */; };
 		7BFC16AD2524BCE700FF6266 /* SentryMessageTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7BFC16AC2524BCE700FF6266 /* SentryMessageTests.swift */; };
@@ -1408,6 +1409,7 @@
 		7BF9EF892722D57100B5BBEF /* SentryInitializeForGettingSubclassesNotCalled.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SentryInitializeForGettingSubclassesNotCalled.h; sourceTree = "<group>"; };
 		7BF9EF8A2722D58700B5BBEF /* SentryInitializeForGettingSubclassesNotCalled.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SentryInitializeForGettingSubclassesNotCalled.m; sourceTree = "<group>"; };
 		7BFA69F527E0840400233199 /* SentryANRTrackingIntegrationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SentryANRTrackingIntegrationTests.swift; sourceTree = "<group>"; };
+		7BFAA6E6297AA16A00E7E02E /* SentryCrashMonitor_CppException_Tests.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = SentryCrashMonitor_CppException_Tests.mm; sourceTree = "<group>"; };
 		7BFC169A2524995700FF6266 /* SentryMessage.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = SentryMessage.h; path = Public/SentryMessage.h; sourceTree = "<group>"; };
 		7BFC16A025249A9D00FF6266 /* SentryMessage.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SentryMessage.m; sourceTree = "<group>"; };
 		7BFC16AC2524BCE700FF6266 /* SentryMessageTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SentryMessageTests.swift; sourceTree = "<group>"; };
@@ -2360,6 +2362,7 @@
 				63FE71FB20DA66EB00CDBAE8 /* SentryCrashMonitor_NSException_Tests.m */,
 				63FE71E820DA66E900CDBAE8 /* SentryCrashMonitor_Signal_Tests.m */,
 				63FE71E120DA66E800CDBAE8 /* SentryCrashMonitor_Tests.m */,
+				7BFAA6E6297AA16A00E7E02E /* SentryCrashMonitor_CppException_Tests.mm */,
 				63FE71F720DA66EB00CDBAE8 /* SentryCrashObjC_Tests.m */,
 				63FE71DB20DA66E700CDBAE8 /* SentryCrashReportFilter_Tests.m */,
 				63FE71EB20DA66E900CDBAE8 /* SentryCrashReportFixer_Tests.m */,
@@ -3903,6 +3906,7 @@
 				7B5B94332657A816002E474B /* SentryAppStartTrackingIntegrationTests.swift in Sources */,
 				0A5370A128A3EC2400B2DCDE /* SentryViewHierarchyTests.swift in Sources */,
 				D8FFE50C2703DBB400607131 /* SwizzlingCallTests.swift in Sources */,
+				7BFAA6E7297AA16A00E7E02E /* SentryCrashMonitor_CppException_Tests.mm in Sources */,
 				D8B76B0828081461000A58C4 /* TestSentryScreenShot.swift in Sources */,
 				A8AFFCD22907DA7600967CD7 /* SentryHttpStatusCodeRangeTests.swift in Sources */,
 				7BE2C7F8257000A4003B66C7 /* SentryTestIntegration.m in Sources */,

Sources/SentryCrash/Recording/Monitors/SentryCrashMonitor_CPPException.cpp

@@ -94,6 +94,17 @@ __cxa_throw(void *thrown_exception, std::type_info *tinfo, void (*dest)(void *))
 }
 }
 
+void
+sentrycrashcm_cppexception_callOriginalTerminationHandler(void)
+{
+    // Can be NULL as the return value of set_terminate can be a NULL pointer; see:
+    // https://en.cppreference.com/w/cpp/error/set_terminate
+    if (g_originalTerminateHandler != NULL) {
+        SentryCrashLOG_DEBUG("Calling original terminate handler.");
+        g_originalTerminateHandler();
+    }
+}
+
 static void
 CPPExceptionTerminate(void)
 {
@@ -167,8 +178,7 @@ CPPExceptionTerminate(void)
     }
     sentrycrashmc_resumeEnvironment(threads, numThreads);
 
-    SentryCrashLOG_DEBUG("Calling original terminate handler.");
-    g_originalTerminateHandler();
+    sentrycrashcm_cppexception_callOriginalTerminationHandler();
 }
 
 // ============================================================================
@@ -197,6 +207,7 @@ setEnabled(bool isEnabled)
             g_originalTerminateHandler = std::set_terminate(CPPExceptionTerminate);
         } else {
             std::set_terminate(g_originalTerminateHandler);
+            g_originalTerminateHandler = NULL;
         }
         g_captureNextStackTrace = isEnabled;
     }

Sources/SentryCrash/Recording/Monitors/SentryCrashMonitor_CPPException.h

@@ -35,6 +35,10 @@ extern "C" {
  */
 SentryCrashMonitorAPI *sentrycrashcm_cppexception_getAPI(void);
 
+/** For testing.
+ */
+void sentrycrashcm_cppexception_callOriginalTerminationHandler(void);
+
 #ifdef __cplusplus
 }
 #endif

Tests/SentryTests/SentryCrash/SentryCrashMonitor_CppException_Tests.mm

@@ -0,0 +1,52 @@
+#import "SentryCrashMonitor_CPPException.h"
+#import <XCTest/XCTest.h>
+
+#include <iostream>
+#include <stdexcept>
+
+@interface SentryCrashMonitor_CppException_Tests : XCTestCase
+
+@end
+
+@implementation SentryCrashMonitor_CppException_Tests
+
+bool terminateCalled = false;
+
+void
+testTerminationHandler()
+{
+    terminateCalled = true;
+}
+
+- (void)setUp
+{
+    [super setUp];
+    terminateCalled = false;
+}
+
+- (void)testCallTerminationHandler_NotEnabled
+{
+
+    std::set_terminate(&testTerminationHandler);
+
+    sentrycrashcm_cppexception_callOriginalTerminationHandler();
+
+    XCTAssertFalse(terminateCalled);
+}
+
+- (void)testCallTerminationHandler_Enabled
+{
+
+    std::set_terminate(&testTerminationHandler);
+
+    SentryCrashMonitorAPI *api = sentrycrashcm_cppexception_getAPI();
+    api->setEnabled(true);
+
+    sentrycrashcm_cppexception_callOriginalTerminationHandler();
+
+    XCTAssertTrue(terminateCalled);
+
+    api->setEnabled(false);
+}
+
+@end