[Haskell-cafe] More on the random idea

[Isaac Dupree]

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Donald Bruce Stewart wrote:
> I've listed the mechanisms we use, and exploits that have been thought
> of, or discovered, over the years, on the page:
> 
>     http://haskell.org/haskellwiki/Safely_running_untrusted_Haskell_code
> 

Lambdabot uses is the technique of using a space at the beginning of the
line to make sure it doesn't do anything special.

However, it seems currently for multiple lines (long string or error
string) it only puts a space if the first character is '@' ('?', '>',
'/', '\001', '\000' are all sent literally).  This behavior seems odd
(why do it for '@'? and why not always a space?).  In XChat the '\000'
prevented the rest of the message from appearing, in the unescaped
version produced by 'error'.

Try (with any string in place of "?botsnack")

@run (\str -> replicate 198 'a' ++ str ++ replicate (199 - length str)
' ') "?botsnack"

or

@run (\str -> error (replicate 188 'a' ++ str)) "?botsnack"

(at least lambdabot doesn't respond to itself:)

Isaac
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