Close console session due to user inactivity (#9890)

Signed-off-by: Prince George <prgeor@microsoft.com>

files/image_config/bash/bash.bashrc

@@ -55,4 +55,4 @@ if [ -x /usr/lib/command-not-found -o -x /usr/share/command-not-found/command-no
 fi
 
 # Automatically log out console ttyS* sessions after 15 minutes of inactivity
-tty | grep ttyS >/dev/null && TMOUT=900
+tty | egrep -q '^/dev/ttyS[[:digit:]]+$' && TMOUT=900

files/image_config/sudoers/sudoers

@@ -54,6 +54,9 @@ ALL     ALL=NOPASSWD: READ_ONLY_CMDS
 # Prevent password related command into syslog
 Defaults!PASSWD_CMDS !syslog
 
+# Make sure sudo password prompt times out after 5 mins
+Defaults passwd_timeout=5
+
 # See sudoers(5) for more information on "#include" directives:
 
 #includedir /etc/sudoers.d