bug#66390: `man' allows to inject arbitrary shell code

[Andreas Schwab]

On Okt 09 2023, Eli Zaretskii wrote:

>> From: lux <lx@shellcodes.org>
>> Cc: 66390@debbugs.gnu.org, michael.albinus@gmx.de
>> Date: Tue, 10 Oct 2023 00:30:06 +0800
>> 
>> There is indeed an code injection vulnerability issue here, for example:
>> 
>>   (man ";ls")    <-- The `ls' command will be executed.
>
> So does this:
>
>   (shell-command "ls")

shell-command does what it is supposed to do.  man, on the other hand,
is supposed to display a manpage, _not_ execute an arbitrary command
line.  While the doc string of the man command says that it runs a
command to do its work, it does not explain how man-args is related to
that command.

-- 
Andreas Schwab, schwab@linux-m68k.org
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