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Re: [SpeechIO-195] speechd v0.54 - morse code support



On Mon, 15 Nov 1999, Kyle Burton wrote:

> It's not safe :)  You have to seperate the arguments into an array 
> when you pass them to system().  I assume the single quotes you have
> used are to account for the possibility of spaces being in $text -- if
> you use the array syntax for system(), the quotes aren't necessary -- 
> actually, the fact taht you used the quotes shows that you were trying
> to protect the spaces from the shell :)  Instead, do something like this:
> 
> system($cmd,$text);
> 
> This passes $text directly into the argv of $cmd, and no shell is ever
> invoked (so it's more efficient too).  To be really safe, you should 
> make sure $cmd is fully pathed, i.e. '/usr/bin/morse' instead of just 
> 'morse'.  Using the array syntax is actualy more efficient too, as
> there is no intermediate shell invoked to parse the arguments.

Cool, that's why I asked.

> Now that I've looked at the code, I kind of relize that we should
> add -T to the command line (which could be a little bit of work
> to make the code taint safe).  The code should be converted to use
> an array (@cmd) instead of a scalar ($cmd) to be safe when performing
> exec()s, pipe open()s, and system() calls.

I've wanted taint checking in there since I'd heard about it, but I
completely forgot about it.

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