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macOS/FUSE-T: Terminate auxiliary FUSE service on dismount #1866

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17 changes: 17 additions & 0 deletions src/Core/Unix/MacOSX/CoreMacOSX.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -317,12 +317,25 @@ namespace VeraCrypt
mountedVolume = ml.front();
}

#ifdef VC_MACOSX_FUSET
pid_t fuseServiceProcessId = FuseService::RequestDismount (mountedVolume->AuxMountPoint,
mountedVolume->SerialInstanceNumber, mountedVolume->SlotNumber);
#endif

list <string> args;
args.push_back ("--");
args.push_back (mountedVolume->AuxMountPoint);

for (int t = 0; true; t++)
{
#ifdef VC_MACOSX_FUSET
try
{
if (GetMountedFilesystems (DevicePath(), mountedVolume->AuxMountPoint).empty())
break;
}
catch (...) { }
#endif
try
{
Process::Execute ("/sbin/umount", args);
Expand All @@ -336,6 +349,10 @@ namespace VeraCrypt
}
}

#ifdef VC_MACOSX_FUSET
FuseService::WaitForDismount (fuseServiceProcessId, mountedVolume->AuxMountPoint, mountedVolume->SlotNumber);
#endif

try
{
mountedVolume->AuxMountPoint.Delete();
Expand Down
198 changes: 198 additions & 0 deletions src/Driver/Fuse/FuseService.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -34,8 +34,10 @@
#include <errno.h>
#include <fcntl.h>
#include <fuse.h>
#include <atomic>
#include <iostream>
#include <signal.h>
#include <sstream>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
Expand All @@ -46,6 +48,13 @@
#include <sys/wait.h>

#include "FuseService.h"
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
#include <fuse_lowlevel.h>
#undef fuse_unmount
#ifdef ERR_SUCCESS
#undef ERR_SUCCESS
#endif
#endif
#include "Platform/FileStream.h"
#include "Platform/MemoryStream.h"
#include "Platform/Serializable.h"
Expand All @@ -62,6 +71,16 @@ namespace VeraCrypt
static const ino_t VC_FUSE_INODE_VOLUME = 2;
static const ino_t VC_FUSE_INODE_CONTROL = 3;
static const ino_t VC_FUSE_INODE_AUX_DEVICE_INFO = 4;
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
static const ino_t VC_FUSE_INODE_SHUTDOWN = 5;
static atomic <bool> FuseServiceShutdownRequested (false);

struct FuseServiceShutdownContext
{
explicit FuseServiceShutdownContext (struct fuse *fuseHandle) : FuseHandle (fuseHandle) { }
struct fuse *FuseHandle;
};
#endif
static const uint64 VC_FUSE_BLOCK_SIZE = 4096;
static const uint64 VC_FUSE_METADATA_SIZE = 64 * 1024;
static const uint64 VC_FUSE_STAT_BLOCK_SIZE = 512;
Expand All @@ -85,6 +104,51 @@ namespace VeraCrypt
return FuseService::GetVolumeInfo();
}

#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
static string fuse_service_get_shutdown_identity ()
{
stringstream identity;
identity << getpid() << " " << FuseService::GetSerialInstanceNumber() << " " << FuseService::GetSlotNumber() << "\n";
return identity.str();
}

static bool fuse_service_parse_shutdown_identity (const string &identity, pid_t &processId, uint64 &serialInstanceNumber, VolumeSlotNumber &slotNumber)
{
long long parsedProcessId;
uint64 parsedSerialInstanceNumber;
VolumeSlotNumber parsedSlotNumber;
stringstream parser (identity);

if (!(parser >> parsedProcessId >> parsedSerialInstanceNumber >> parsedSlotNumber))
return false;

parser >> ws;
if (!parser.eof() || parsedProcessId <= 1 || static_cast <pid_t> (parsedProcessId) != parsedProcessId)
return false;

processId = static_cast <pid_t> (parsedProcessId);
serialInstanceNumber = parsedSerialInstanceNumber;
slotNumber = parsedSlotNumber;
return true;
}

static TC_THREAD_PROC fuse_service_shutdown (void *contextArg)
{
unique_ptr <FuseServiceShutdownContext> context (static_cast <FuseServiceShutdownContext *> (contextArg));

// Let the write reply reach the caller before closing FUSE-T's channel.
Thread::Sleep (100);
fuse_exit (context->FuseHandle);

struct fuse_session *session = fuse_get_session (context->FuseHandle);
struct fuse_chan *channel = session ? fuse_session_next_chan (session, NULL) : NULL;
if (channel)
fuse_unmount (NULL, channel);

return 0;
}
#endif

static int fuse_service_fill_dir_entry (void *buf, fuse_fill_dir_t filler, const char *name, mode_t mode, ino_t ino, off_t nextOff)
{
struct stat st;
Expand Down Expand Up @@ -234,6 +298,16 @@ namespace VeraCrypt
statData->st_ino = VC_FUSE_INODE_CONTROL;
fuse_service_set_stat_blocks (statData);
}
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
else if (strcmp (path, FuseService::GetShutdownPath()) == 0)
{
statData->st_mode = S_IFREG | 0600;
statData->st_nlink = 1;
statData->st_size = fuse_service_get_shutdown_identity().size();
statData->st_ino = VC_FUSE_INODE_SHUTDOWN;
fuse_service_set_stat_blocks (statData);
}
#endif
else
{
return -ENOENT;
Expand Down Expand Up @@ -330,6 +404,14 @@ namespace VeraCrypt
fi->direct_io = 1;
return 0;
}

#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
if (strcmp (path, FuseService::GetShutdownPath()) == 0)
{
fi->direct_io = 1;
return 0;
}
#endif
}
catch (...)
{
Expand Down Expand Up @@ -412,6 +494,24 @@ namespace VeraCrypt
outBuf.CopyFrom (infoBuf->GetRange (offset, size));
return size;
}

#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
if (strcmp (path, FuseService::GetShutdownPath()) == 0)
{
string identity = fuse_service_get_shutdown_identity();
if (offset < 0)
return -EINVAL;

if (offset >= (off_t) identity.size())
return 0;

if (offset + size > identity.size())
size = identity.size() - offset;

memcpy (buf, identity.data() + offset, size);
return size;
}
#endif
}
catch (...)
{
Expand Down Expand Up @@ -461,6 +561,10 @@ namespace VeraCrypt
return 0;
if (fuse_service_fill_dir_entry (buf, filler, FuseService::GetAuxDeviceInfoPath() + 1, S_IFREG | 0600, VC_FUSE_INODE_AUX_DEVICE_INFO, 0) != 0)
return 0;
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
if (fuse_service_fill_dir_entry (buf, filler, FuseService::GetShutdownPath() + 1, S_IFREG | 0600, VC_FUSE_INODE_SHUTDOWN, 0) != 0)
return 0;
#endif
}
catch (...)
{
Expand Down Expand Up @@ -506,6 +610,42 @@ namespace VeraCrypt
FuseService::ReceiveAuxDeviceInfo (ConstBufferPtr ((const uint8 *) buf, size));
return size;
}

#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
if (strcmp (path, FuseService::GetShutdownPath()) == 0)
{
pid_t processId;
uint64 serialInstanceNumber;
VolumeSlotNumber slotNumber;
struct fuse_context *context = fuse_get_context();

if (offset != 0 || !context || !context->fuse
|| !fuse_service_parse_shutdown_identity (string (buf, size), processId, serialInstanceNumber, slotNumber)
|| processId != getpid()
|| serialInstanceNumber != FuseService::GetSerialInstanceNumber()
|| slotNumber != FuseService::GetSlotNumber())
return -EINVAL;

bool expected = false;
if (FuseServiceShutdownRequested.compare_exchange_strong (expected, true))
{
try
{
unique_ptr <FuseServiceShutdownContext> shutdownContext (new FuseServiceShutdownContext (context->fuse));
Thread shutdownThread;
shutdownThread.Start (fuse_service_shutdown, shutdownContext.get());
shutdownContext.release();
shutdownThread.Detach();
}
catch (...)
{
FuseServiceShutdownRequested = false;
throw;
}
}
return size;
}
#endif
}
#ifdef TC_FREEBSD
// FreeBSD apparently retries failed write operations forever, which may lead to a system crash.
Expand Down Expand Up @@ -742,6 +882,64 @@ namespace VeraCrypt
fuseServiceControl.Close();
}

#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
pid_t FuseService::RequestDismount (const DirectoryPath &fuseMountPoint, uint64 serialInstanceNumber, VolumeSlotNumber slotNumber)
{
shared_ptr <File> shutdownFile (new File);
shutdownFile->Open (string (fuseMountPoint) + GetShutdownPath());

FileStream shutdownReader (shutdownFile);
string identity = shutdownReader.ReadToEnd();
shutdownFile->Close();
if (identity.empty() || identity.size() > 256)
throw ParameterIncorrect (SRC_POS);

pid_t processId;
uint64 serviceSerialInstanceNumber;
VolumeSlotNumber serviceSlotNumber;
if (!fuse_service_parse_shutdown_identity (identity, processId, serviceSerialInstanceNumber, serviceSlotNumber)
|| serviceSerialInstanceNumber != serialInstanceNumber || serviceSlotNumber != slotNumber)
{
stringstream logMessage;
logMessage << "Refusing to shut down mismatched VeraCrypt FUSE service: slot=" << slotNumber
<< ", auxiliary mount=" << string (fuseMountPoint);
SystemLog::WriteError (logMessage.str());
throw ParameterIncorrect (SRC_POS);
}

shutdownFile->Open (string (fuseMountPoint) + GetShutdownPath(), File::OpenWrite);
shutdownFile->Write (ConstBufferPtr (reinterpret_cast <const uint8 *> (identity.data()), identity.size()));
shutdownFile->Close();
return processId;
}

void FuseService::WaitForDismount (pid_t processId, const DirectoryPath &fuseMountPoint, VolumeSlotNumber slotNumber, int timeOut)
{
for (int timeTaken = 0; ; timeTaken += 100)
{
if (kill (processId, 0) == -1)
{
if (errno == ESRCH)
return;

if (errno != EPERM)
throw SystemException (SRC_POS);
}

if (timeTaken >= timeOut)
{
stringstream logMessage;
logMessage << "VeraCrypt FUSE service did not terminate after shutdown request: pid=" << processId
<< ", slot=" << slotNumber << ", auxiliary mount=" << string (fuseMountPoint);
SystemLog::WriteError (logMessage.str());
throw TimeOut (SRC_POS);
}

Thread::Sleep (100);
}
}
#endif

void FuseService::WriteVolumeSectors (const ConstBufferPtr &buffer, uint64 byteOffset)
{
if (!MountedVolume)
Expand Down
9 changes: 9 additions & 0 deletions src/Driver/Fuse/FuseService.h
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Original file line number Diff line number Diff line change
Expand Up @@ -48,9 +48,14 @@ namespace VeraCrypt
static const char *GetAuxDeviceInfoPath () { return "/aux-device-info"; }
static const char *GetControlPath () { return "/control"; }
static const char *GetVolumeImagePath ();
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
static const char *GetShutdownPath () { return "/shutdown"; }
#endif
static string GetDeviceType () { return "veracrypt"; }
static gid_t GetGroupId () { return GroupId; }
static uid_t GetUserId () { return UserId; }
static uint64 GetSerialInstanceNumber () { return OpenVolumeInfo.SerialInstanceNumber; }
static VolumeSlotNumber GetSlotNumber () { return SlotNumber; }
static shared_ptr <Buffer> GetAuxDeviceInfo ();
static shared_ptr <Buffer> GetVolumeInfo ();
static uint64 GetVolumeSize ();
Expand All @@ -59,6 +64,10 @@ namespace VeraCrypt
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());
#if defined(TC_MACOSX) && defined(VC_MACOSX_FUSET)
static pid_t RequestDismount (const DirectoryPath &fuseMountPoint, uint64 serialInstanceNumber, VolumeSlotNumber slotNumber);
static void WaitForDismount (pid_t processId, const DirectoryPath &fuseMountPoint, VolumeSlotNumber slotNumber, int timeOut = 10000);
#endif
static void WriteVolumeSectors (const ConstBufferPtr &buffer, uint64 byteOffset);

protected:
Expand Down