If /dev/tty is not available and no I/O logging plugins are configured,

fall back on exec_nopty() even if the policy plugin requested a pty.
We never allocate a pty when sudo is not run from a terminal anyway.

src/exec.c

@@ -380,34 +380,37 @@ sudo_execute(struct command_details *details, struct command_status *cstat)
     }
 
     /*
-     * If we have an I/O plugin or the policy plugin has requested one, we
-     * need to allocate a pty.
+     * Run the command in a new pty if there is an I/O plugin or the policy
+     * has requested a pty.  If /dev/tty is unavailable and no I/O plugin
+     * is configured, this returns false and we run the command without a pty.
      */
     if (!TAILQ_EMPTY(&io_plugins) || ISSET(details->flags, CD_USE_PTY)) {
-	/*
-	 * Run the command in a new pty, wait for it to finish and
-	 * send the plugin the exit status.
-	 */
-	exec_pty(details, cstat);
-    } else if (!ISSET(details->flags, CD_SET_TIMEOUT|CD_SUDOEDIT) &&
-	policy_plugin.u.policy->close == NULL) {
+	if (exec_pty(details, cstat))
+	    goto done;
+    }
+
     /*
      * If we are not running the command in a pty, we were not invoked
      * as sudoedit, there is no command timeout and there is no close
      * function, just exec directly.  Only returns on error.
      */
+    if (!ISSET(details->flags, CD_SET_TIMEOUT|CD_SUDOEDIT) &&
+	policy_plugin.u.policy->close == NULL) {
 	if (!sudo_terminated(cstat)) {
 	    exec_cmnd(details, -1);
 	    cstat->type = CMD_ERRNO;
 	    cstat->val = errno;
 	}
-    } else {
+	goto done;
+    }
+
     /*
-	 * No pty but we need to wait for the command to finish to
-	 * send the plugin the exit status.
+     * Run the command in the existing tty (if any) and wait for it to finish.
      */
     exec_nopty(details, cstat);
-    }
+
+done:
+    /* The caller will run any plugin close functions. */
     debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);
 }
 

src/exec_nopty.c

@@ -340,7 +340,7 @@ free_exec_closure_nopty(struct exec_closure_nopty *ec)
 /*
  * Execute a command and wait for it to finish.
  */
-int
+void
 exec_nopty(struct command_details *details, struct command_status *cstat)
 {
     struct exec_closure_nopty ec = { 0 };
@@ -371,7 +371,7 @@ exec_nopty(struct command_details *details, struct command_status *cstat)
     /* Check for early termination or suspend signals before we fork. */
     if (sudo_terminated(cstat)) {
 	sigprocmask(SIG_SETMASK, &oset, NULL);
-	debug_return_int(0);
+	debug_return;
     }
 
     ec.cmnd_pid = sudo_debug_fork();
@@ -436,7 +436,7 @@ exec_nopty(struct command_details *details, struct command_status *cstat)
 
     /* Free things up. */
     free_exec_closure_nopty(&ec);
-    debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);
+    debug_return;
 }
 
 /*

src/exec_pty.c

@@ -1149,7 +1149,7 @@ free_exec_closure_pty(struct exec_closure_pty *ec)
  * This is a little bit tricky due to how POSIX job control works and
  * we fact that we have two different controlling terminals to deal with.
  */
-int
+bool
 exec_pty(struct command_details *details, struct command_status *cstat)
 {
     int io_pipe[3][2] = { { -1, -1 }, { -1, -1 }, { -1, -1 } };
@@ -1169,6 +1169,9 @@ exec_pty(struct command_details *details, struct command_status *cstat)
     if (pty_setup(details->euid, user_details.tty)) {
 	if (ISSET(details->flags, CD_SET_UTMP))
 	    utmp_user = details->utmp_user ? details->utmp_user : user_details.username;
+    } else if (TAILQ_EMPTY(&io_plugins)) {
+	/* Not logging I/O and didn't allocate a pty. */
+	debug_return_bool(false);
     }
 
     /*
@@ -1332,7 +1335,7 @@ exec_pty(struct command_details *details, struct command_status *cstat)
     /* Check for early termination or suspend signals before we fork. */
     if (sudo_terminated(cstat)) {
 	sigprocmask(SIG_SETMASK, &oset, NULL);
-	debug_return_int(0);
+	debug_return_int(true);
     }
 
     ec.monitor_pid = sudo_debug_fork();
@@ -1422,7 +1425,7 @@ exec_pty(struct command_details *details, struct command_status *cstat)
     TAILQ_FOREACH_SAFE(sigfwd, &ec.sigfwd_list, entries, sigfwd_next) {
 	free(sigfwd);
     }
-    debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);
+    debug_return_bool(true);
 }
 
 /*

src/sudo_exec.h

@@ -92,10 +92,10 @@ int sudo_execve(int fd, const char *path, char *const argv[], char *envp[], bool
 char **disable_execute(char *envp[], const char *dso);
 
 /* exec_nopty.c */
-int exec_nopty(struct command_details *details, struct command_status *cstat);
+void exec_nopty(struct command_details *details, struct command_status *cstat);
 
 /* exec_pty.c */
-int exec_pty(struct command_details *details, struct command_status *cstat);
+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];