VSMB fix bugcheck by keeping handle open to empty default share

cmd/containerd-shim-runhcs-v1/pod.go

@@ -187,6 +187,7 @@ func createPod(ctx context.Context, events publisher, req *task.CreateTaskReques
 			}
 		case *uvm.OptionsWCOW:
 			wopts := (opts).(*uvm.OptionsWCOW)
+			wopts.BundleDirectory = req.Bundle
 			err = initializeWCOWBootFiles(ctx, wopts, req.Rootfs, s)
 			if err != nil {
 				return nil, err

cmd/gcs-sidecar/main.go

@@ -26,6 +26,8 @@ import (
 	sidecar "github.com/Microsoft/hcsshim/internal/gcs-sidecar"
 )
 
+var vsmbKeepAliveHandle windows.Handle
+
 var (
 	defaultLogFile  = "C:\\gcs-sidecar-logs.log"
 	defaultLogLevel = "trace"
@@ -182,8 +184,8 @@ func main() {
 		}
 	}
 
-	logrus.Println("Initializing VSMB redirector..")
-	sidecar.VsmbMain()
+	logrus.Println("Initializing VSMB redirector!!!")
+	sidecar.VsmbMain(&vsmbKeepAliveHandle)
 
 	// 1. Start external server to connect with inbox GCS
 	listener, err := winio.ListenHvsock(&winio.HvsockAddr{

internal/gcs-sidecar/vsmb.go

@@ -27,6 +27,9 @@ const (
 	LmrInstanceFlagAllowGuestAuth         = 0x8
 	LmrInstanceFlagSupportsDirectmappedIo = 0x10
 	SmbCeTransportTypeVmbus               = 3
+
+	FileReadAttributes      = 0x00000080
+	FileFlagBackupSemantics = 0x02000000
 )
 
 type IOStatusBlock struct {
@@ -166,7 +169,7 @@ func isLanmanWorkstationRunning() (bool, error) {
 	return status.State == svc.Running, nil
 }
 
-func VsmbMain() {
+func VsmbMain(vsmbKeepAliveHandle *windows.Handle) {
 	logrus.Info("Starting VSMB initialization...")
 
 	logrus.Debug("Configuring LanmanWorkstation service...")
@@ -329,4 +332,31 @@ func VsmbMain() {
 	} else {
 		logrus.Errorf("NtFsControlFile failed: 0x%08X", status)
 	}
+
+	const (
+		device = `\\?\GLOBALROOT\Device\vmsmb\VSMB-{dcc079ae-60ba-4d07-847c-3493609c0870}\defaultEmptyShare`
+	)
+
+	devicePtr, nerr := windows.UTF16PtrFromString(device)
+	if nerr != nil {
+		logrus.WithError(nerr).Errorf("invalid device name %q", device)
+		return
+	}
+	vsmbHandle, err := windows.CreateFile(
+		devicePtr,
+		FileReadAttributes,
+		windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE|windows.FILE_SHARE_DELETE,
+		nil,
+		windows.OPEN_EXISTING,
+		FileFlagBackupSemantics,
+		0,
+	)
+
+	if err != nil {
+		logrus.WithError(err).Errorf("Failed to open %s", device)
+		return
+	}
+
+	*vsmbKeepAliveHandle = vsmbHandle
+	logrus.Infof("VSMB connection will be alive...")
 }

internal/uvm/create.go

@@ -137,6 +137,7 @@ type ConfidentialCommonOptions struct {
 	SecurityPolicyEnabled  bool   // Set when there is a security policy to apply on actual SNP hardware, use this rathen than checking the string length
 	SecurityPolicyEnforcer string // Set which security policy enforcer to use (open door or rego). This allows for better fallback mechanic.
 	UVMReferenceInfoFile   string // Path to the file that contains the signed UVM measurements
+	BundleDirectory        string // This allows paths to be constructed relative to a per-VM bundle directory.
 }
 
 func verifyWCOWBootFiles(bootFiles *WCOWBootFiles) error {

internal/uvm/create_lcow.go

@@ -92,7 +92,6 @@ const (
 type ConfidentialLCOWOptions struct {
 	*ConfidentialCommonOptions
 	UseGuestStateFile  bool   // Use a vmgs file that contains a kernel and initrd, required for SNP
-	BundleDirectory    string // pod bundle directory
 	DmVerityRootFsVhd  string // The VHD file (bound to the vmgs file via embedded dmverity hash data file) to load.
 	DmVerityMode       bool   // override to be able to turn off dmverity for debugging
 	DmVerityCreateArgs string // set dm-verity args when booting with verity in non-SNP mode

internal/uvm/create_wcow.go

@@ -466,6 +466,30 @@ func prepareSecurityConfigDoc(ctx context.Context, uvm *UtilityVM, opts *Options
 		scsi.Slot{Controller: 0, LUN: 1},
 		scsi.Slot{Controller: 0, LUN: 2})
 
+	vsmbOpts := &hcsschema.VirtualSmbShareOptions{
+		ReadOnly:  true,
+		ShareRead: true,
+		NoOplocks: true,
+	}
+
+	// Construct a per-VM share directory relative to the bundle. The directory EmptyDoNotModify should be left empty.
+	sharePath := filepath.Join(opts.BundleDirectory, "EmptyDoNotModify")
+
+	// Ensure the directory exists.
+	if err := os.MkdirAll(sharePath, os.ModePerm); err != nil {
+		return nil, fmt.Errorf("failed to create VSMB default empty share directory %q: %w", sharePath, err)
+	}
+
+	if err := wclayer.GrantVmAccess(ctx, uvm.id, sharePath); err != nil {
+		return nil, errors.Wrap(err, "failed to grant vm access to VSMB default empty share directory")
+	}
+
+	doc.VirtualMachine.Devices.VirtualSmb.Shares = []hcsschema.VirtualSmbShare{{
+		Name:    "defaultEmptyShare",
+		Path:    sharePath,
+		Options: vsmbOpts,
+	}}
+
 	return doc, nil
 }