ASCII Control Characters as function names

[Marcus Hildum]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: x86_64-pc-linux-gnu-gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H   -I. -I./include -I. -I./include -I./lib  
-DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
 -DSTANDARD_UTILS_PATH='/bin:/usr/bin:/sbin:/usr/sbin' 
-DSYS_BASHRC='/etc/bash/bashrc' -DSYS_BASH_LOGOUT='/etc/bash/bash_logout' 
-DNON_INTERACTIVE_LOGIN_SHELLS -DSSH_SOURCE_BASHRC -O2 -pipe -march=native
uname output: Linux mirkwood 3.19.2-gentoo #1 SMP Sat Mar 28 16:47:29 PDT 2015 
x86_64 Intel(R) Core(TM) i5-2540M CPU @ 2.60GHz GenuineIntel GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 4.3
Patch Level: 33
Release Status: release

Description:
        It is possible to supply many ascii control characters as function
        names. This allows obfuscation of function calls because the majority of
        these are non printing characters.

        
https://github.com/airencracken/why/blob/master/control_character_functions.sh

Repeat-By:
        Define a function with a control character, then call it.
Fix:
        Disallow functions to be named after control characters or non-printing
        characters in general.