PTY

How buffer overflow happens in C kernel PTY subsystem (tty_ptmx.c) and how to fix it

A stack buffer overflow vulnerability was discovered in `tty_ptmx.c`, the kernel-level pseudo-terminal multiplexer component, where an unchecked `sprintf()` call at line 293 could overflow the `device_name` buffer by combining `root_path` and `dev_rel_path` without bounds validation. Because this code executes in kernel context during PTY device creation, successful exploitation could lead to kernel memory corruption, privilege escalation, or system crashes. The fix replaces the unbounded `sprin