Fix int overflow

Azure · Jun 17, 2021 · 7879a6d · 7879a6d
1 parent 8db1f69
commit 7879a6d
Showing 1 changed file with 18 additions and 5 deletions.
diff --git a/winterm/ansi.go b/winterm/ansi.go
@@ -163,15 +163,28 @@ func ensureInRange(n int16, min int16, max int16) int16 {
 
 func GetStdFile(nFile int) (*os.File, uintptr) {
 	var file *os.File
-	switch nFile {
-	case syscall.STD_INPUT_HANDLE, windows.STD_INPUT_HANDLE:
+
+	// syscall uses negative numbers
+	// windows package uses very big uint32
+	// Keep these switches split so we don't have to convert ints too much.
+	switch uint32(nFile) {
+	case windows.STD_INPUT_HANDLE:
 		file = os.Stdin
-	case syscall.STD_OUTPUT_HANDLE, windows.STD_OUTPUT_HANDLE:
+	case windows.STD_OUTPUT_HANDLE:
 		file = os.Stdout
-	case syscall.STD_ERROR_HANDLE, windows.STD_ERROR_HANDLE:
+	case windows.STD_ERROR_HANDLE:
 		file = os.Stderr
 	default:
-		panic(fmt.Errorf("Invalid standard handle identifier: %v", nFile))
+		switch nFile {
+		case syscall.STD_INPUT_HANDLE:
+			file = os.Stdin
+		case syscall.STD_OUTPUT_HANDLE:
+			file = os.Stdout
+		case syscall.STD_ERROR_HANDLE:
+			file = os.Stderr
+		default:
+			panic(fmt.Errorf("Invalid standard handle identifier: %v", nFile))
+		}
 	}
 
 	fd, err := syscall.GetStdHandle(nFile)