From 23d4452f5be005b3a8d01895d27c9bff29422a98 Mon Sep 17 00:00:00 2001
From: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date: Sat, 26 Sep 2026 03:38:01 +0200
Subject: [PATCH] macOS: preserve FUSE service identity in fallback metadata

Generate the session serial before forking and reuse it in the service
and fallback mount metadata.

This keeps PR #1866's shutdown identity check consistent when control
metadata cannot be read.
---
 src/Core/Unix/CoreUnix.cpp      | 12 +++++++++---
 src/Driver/Fuse/FuseService.cpp | 16 +++++++++++-----
 src/Driver/Fuse/FuseService.h   |  7 ++++---
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/Core/Unix/CoreUnix.cpp b/src/Core/Unix/CoreUnix.cpp
index fee1eafb..34845c90 100644
--- a/src/Core/Unix/CoreUnix.cpp
+++ b/src/Core/Unix/CoreUnix.cpp
@@ -1169,9 +1169,17 @@ namespace VeraCrypt
 			}
 		}
 
+#ifdef VC_MACOSX_FUSET
+		uint64 fuseServiceSerialInstanceNumber;
+#endif
+
 		try
 		{
+#ifdef VC_MACOSX_FUSET
+			fuseServiceSerialInstanceNumber = FuseService::Mount (volume, options.SlotNumber, fuseMountPoint);
+#else
 			FuseService::Mount (volume, options.SlotNumber, fuseMountPoint);
+#endif
 		}
 		catch (...)
 		{
@@ -1295,9 +1303,7 @@ namespace VeraCrypt
 			mountedVolume->AuxMountPoint = fuseMountPoint;
 			mountedVolume->VirtualDevice = mountedVirtualDevice;
 
-			struct timeval tv;
-			gettimeofday (&tv, NULL);
-			mountedVolume->SerialInstanceNumber = (uint64) tv.tv_sec * 1000000ULL + tv.tv_usec;
+			mountedVolume->SerialInstanceNumber = fuseServiceSerialInstanceNumber;
 
 			if (!options.NoFilesystem)
 			{
diff --git a/src/Driver/Fuse/FuseService.cpp b/src/Driver/Fuse/FuseService.cpp
index 581b6ae9..fce2bf7e 100644
--- a/src/Driver/Fuse/FuseService.cpp
+++ b/src/Driver/Fuse/FuseService.cpp
@@ -790,7 +790,7 @@ namespace VeraCrypt
 		return MountedVolume->GetSize();
 	}
 
-	void FuseService::Mount (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber, const string &fuseMountPoint)
+	uint64 FuseService::Mount (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber, const string &fuseMountPoint)
 	{
 		list <string> args;
 		args.push_back (FuseService::GetDeviceType());
@@ -826,7 +826,13 @@ namespace VeraCrypt
 		args.push_back ("use_ino");
 #endif
 
-		ExecFunctor execFunctor (openVolume, slotNumber);
+		// Generate the serial before forking so the caller can reuse it if
+		// the service's control metadata cannot be read.
+		struct timeval tv;
+		throw_sys_if (gettimeofday (&tv, NULL) != 0);
+		const uint64 serialInstanceNumber = (uint64)tv.tv_sec * 1000000ULL + tv.tv_usec;
+
+		ExecFunctor execFunctor (openVolume, slotNumber, serialInstanceNumber);
 		Process::Execute ("fuse", args, -1, &execFunctor);
 
 		for (int t = 0; true; t++)
@@ -846,6 +852,8 @@ namespace VeraCrypt
 
 			Thread::Sleep (100);
 		}
+
+		return serialInstanceNumber;
 	}
 
 	void FuseService::ReadVolumeSectors (const BufferPtr &buffer, uint64 byteOffset)
@@ -964,9 +972,7 @@ namespace VeraCrypt
 
 	void FuseService::ExecFunctor::operator() (int argc, char *argv[])
 	{
-		struct timeval tv;
-		gettimeofday (&tv, NULL);
-		FuseService::OpenVolumeInfo.SerialInstanceNumber = (uint64)tv.tv_sec * 1000000ULL + tv.tv_usec;
+		FuseService::OpenVolumeInfo.SerialInstanceNumber = SerialInstanceNumber;
 
 		FuseService::MountedVolume = MountedVolume;
 		FuseService::SlotNumber = SlotNumber;
diff --git a/src/Driver/Fuse/FuseService.h b/src/Driver/Fuse/FuseService.h
index 4686c1b9..ba4be10e 100644
--- a/src/Driver/Fuse/FuseService.h
+++ b/src/Driver/Fuse/FuseService.h
@@ -27,8 +27,8 @@ namespace VeraCrypt
 	protected:
 		struct ExecFunctor : public ProcessExecFunctor
 		{
-			ExecFunctor (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber)
-				: MountedVolume (openVolume), SlotNumber (slotNumber)
+			ExecFunctor (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber, uint64 serialInstanceNumber)
+				: MountedVolume (openVolume), SlotNumber (slotNumber), SerialInstanceNumber (serialInstanceNumber)
 			{
 			}
 			virtual void operator() (int argc, char *argv[]);
@@ -36,6 +36,7 @@ namespace VeraCrypt
 		protected:
 			shared_ptr <Volume> MountedVolume;
 			VolumeSlotNumber SlotNumber;
+			uint64 SerialInstanceNumber;
 		};
 
 		friend struct ExecFunctor;
@@ -60,7 +61,7 @@ namespace VeraCrypt
 		static shared_ptr <Buffer> GetVolumeInfo ();
 		static uint64 GetVolumeSize ();
 		static uint64 GetVolumeSectorSize () { return MountedVolume->GetSectorSize(); }
-		static void Mount (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber, const string &fuseMountPoint);
+		static uint64 Mount (shared_ptr <Volume> openVolume, VolumeSlotNumber slotNumber, const string &fuseMountPoint);
 		static void ReadVolumeSectors (const BufferPtr &buffer, uint64 byteOffset);
 		static void ReceiveAuxDeviceInfo (const ConstBufferPtr &buffer);
 		static void SendAuxDeviceInfo (const DirectoryPath &fuseMountPoint, const DevicePath &virtualDevice, const DevicePath &loopDevice = DevicePath());