Register pty cleanup function in exec_pty(), not exec_cmnd_pty().

We want it to execute in the main sudo process, not the monitor.

src/exec_monitor.c

@@ -1,7 +1,7 @@
 /*
  * SPDX-License-Identifier: ISC
  *
- * Copyright (c) 2009-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ * Copyright (c) 2009-2023 Todd C. Miller <Todd.Miller@sudo.ws>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -354,9 +354,6 @@ exec_cmnd_pty(struct command_details *details, sigset_t *mask,
     volatile pid_t self = getpid();
     debug_decl(exec_cmnd_pty, SUDO_DEBUG_EXEC);
 
-    /* Register cleanup function */
-    sudo_fatal_callback_register(pty_cleanup);
-
     /* Set command process group here too to avoid a race. */
     setpgid(0, self);
 

src/exec_pty.c

@@ -67,7 +67,7 @@ static void schedule_signal(struct exec_closure *ec, int signo);
 /*
  * Cleanup hook for sudo_fatal()/sudo_fatalx()
  */
-void
+static void
 pty_cleanup(void)
 {
     debug_decl(cleanup, SUDO_DEBUG_EXEC);
@@ -1075,6 +1075,9 @@ exec_pty(struct command_details *details, struct command_status *cstat)
     if (!pty_setup(details, user_details.tty))
 	debug_return_bool(false);
 
+    /* Register cleanup function */
+    sudo_fatal_callback_register(pty_cleanup);
+
     /*
      * We communicate with the monitor over a bi-directional pair of sockets.
      * Parent sends signal info to monitor and monitor sends back wait status.
@@ -1284,6 +1287,10 @@ exec_pty(struct command_details *details, struct command_status *cstat)
 	    close(io_pipe[STDOUT_FILENO][0]);
 	if (io_pipe[STDERR_FILENO][0] != -1)
 	    close(io_pipe[STDERR_FILENO][0]);
+
+	/* Only run the cleanup hook in the parent. */
+	sudo_fatal_callback_deregister(pty_cleanup);
+
 	/*                      
 	 * If stdin/stdout is not a tty, start command in the background
 	 * since it might be part of a pipeline that reads from /dev/tty.

src/sudo_exec.h

@@ -212,7 +212,6 @@ void exec_nopty(struct command_details *details, struct command_status *cstat);
 
 /* exec_pty.c */
 bool exec_pty(struct command_details *details, struct command_status *cstat);
-void pty_cleanup(void);
 int pty_make_controlling(void);
 extern int io_fds[6];