chore: import upstream snapshot with attribution

internal/validate/input.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package validate
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/larksuite/cli/internal/charcheck"
+)
+
+// RejectControlChars rejects C0 control characters (except \t and \n) and
+// dangerous Unicode characters from user input.
+//
+// Delegates to charcheck.RejectControlChars — the single source of truth
+// for character-level security checks.
+func RejectControlChars(value, flagName string) error {
+	return charcheck.RejectControlChars(value, flagName)
+}
+
+// RejectCRLF rejects strings containing carriage return (\r) or line feed (\n).
+// These characters enable MIME/HTTP header injection and must never appear in
+// header field names, values, Content-ID, or filename parameters.
+func RejectCRLF(value, fieldName string) error {
+	if strings.ContainsAny(value, "\r\n") {
+		return fmt.Errorf("%s contains invalid line break characters", fieldName)
+	}
+	return nil
+}
+
+// StripQueryFragment removes any ?query or #fragment suffix from a URL path.
+// API parameters must go through structured --params flags, not embedded in
+// the path, to prevent parameter injection and behaviour confusion.
+func StripQueryFragment(path string) string {
+	for i := 0; i < len(path); i++ {
+		if path[i] == '?' || path[i] == '#' {
+			return path[:i]
+		}
+	}
+	return path
+}