Broaden scope of host path types to skip processing in Windows

pkg/kubelet/kubelet_pods.go

@@ -215,15 +215,16 @@ func makeMounts(pod *v1.Pod, podDir string, container *v1.Container, hostName, h
 			}
 		}
 
-		// Docker Volume Mounts fail on Windows if it is not of the form C:/ nor a named pipe starting with \\.\pipe\
+		// Docker Volume Mounts fail on Windows if it is not of the form C:/
 		containerPath := mount.MountPath
 		if runtime.GOOS == "windows" {
-			if !volumeutil.IsWindowsNamedPipe(runtime.GOOS, hostPath) && (strings.HasPrefix(hostPath, "/") || strings.HasPrefix(hostPath, "\\")) && !strings.Contains(hostPath, ":") {
+			// Append C: only if it looks like a local path. Do not process UNC path/SMB shares/named pipes
+			if (strings.HasPrefix(hostPath, "/") || strings.HasPrefix(hostPath, "\\")) && !strings.Contains(hostPath, ":") && !volumeutil.IsWindowsUNCPath(runtime.GOOS, hostPath) {
 				hostPath = "c:" + hostPath
 			}
 		}
-		// IsAbs returns false for named pipes (\\.\pipe\...) in Windows. So check for it specifically and skip MakeAbsolutePath
-		if !volumeutil.IsWindowsNamedPipe(runtime.GOOS, containerPath) && !filepath.IsAbs(containerPath) {
+		// IsAbs returns false for UNC path/SMB shares/named pipes in Windows. So check for those specifically and skip MakeAbsolutePath
+		if !volumeutil.IsWindowsUNCPath(runtime.GOOS, containerPath) && !filepath.IsAbs(containerPath) {
 			containerPath = volumeutil.MakeAbsolutePath(runtime.GOOS, containerPath)
 		}
 

pkg/volume/util/util.go

@@ -945,8 +945,15 @@ func CheckPersistentVolumeClaimModeBlock(pvc *v1.PersistentVolumeClaim) bool {
 	return utilfeature.DefaultFeatureGate.Enabled(features.BlockVolume) && pvc.Spec.VolumeMode != nil && *pvc.Spec.VolumeMode == v1.PersistentVolumeBlock
 }
 
-func IsWindowsNamedPipe(goos, path string) bool {
-	if goos == "windows" && strings.HasPrefix(path, `\\.\pipe\`) {
+// IsWindowsUNCPath checks if path is prefixed with \\
+// This can be used to skip any processing of paths
+// that point to SMB shares, local named pipes and local UNC path
+func IsWindowsUNCPath(goos, path string) bool {
+	if goos != "windows" {
+		return false
+	}
+	// Check for UNC prefix \\
+	if strings.HasPrefix(path, `\\`) {
 		return true
 	}
 	return false

pkg/volume/util/util_test.go

@@ -2373,43 +2373,53 @@ func TestGetWindowsPath(t *testing.T) {
 	}
 }
 
-func TestIsWindowsNamedPipe(t *testing.T) {
+func TestIsWindowsUNCPath(t *testing.T) {
 	tests := []struct {
 		goos      string
 		path      string
-		isNamedPipe bool
+		isUNCPath bool
 	}{
 		{
 			goos:      "linux",
 			path:      `/usr/bin`,
-			isNamedPipe: false,
+			isUNCPath: false,
 		},
 		{
 			goos:      "linux",
 			path:      `\\.\pipe\foo`,
-			isNamedPipe: false,
+			isUNCPath: false,
 		},
 		{
 			goos:      "windows",
 			path:      `C:\foo`,
-			isNamedPipe: false,
+			isUNCPath: false,
 		},
 		{
 			goos:      "windows",
-			path:        `\\.\invalid`,
-			isNamedPipe: false,
+			path:      `\\server\share\foo`,
+			isUNCPath: true,
+		},
+		{
+			goos:      "windows",
+			path:      `\\?\server\share`,
+			isUNCPath: true,
+		},
+		{
+			goos:      "windows",
+			path:      `\\?\c:\`,
+			isUNCPath: true,
 		},
 		{
 			goos:      "windows",
 			path:      `\\.\pipe\valid_pipe`,
-			isNamedPipe: true,
+			isUNCPath: true,
 		},
 	}
 
 	for _, test := range tests {
-		result := IsWindowsNamedPipe(test.goos, test.path)
-		if result != test.isNamedPipe {
-			t.Errorf("IsWindowsNamedPipe(%v) returned (%v), expected (%v)", test.path, result, test.isNamedPipe)
+		result := IsWindowsUNCPath(test.goos, test.path)
+		if result != test.isUNCPath {
+			t.Errorf("IsWindowsUNCPath(%v) returned (%v), expected (%v)", test.path, result, test.isUNCPath)
 		}
 	}
 }