Re: [Haskell-cafe] Re: ANN: System.FilePath 0.9

Stephane Bortzmeyer wrote:

On Mon, Jul 17, 2006 at 03:07:51AM +0100, Neil Mitchell wrote a message of 64 lines which said:

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How about adding something like "restrictFilePaths :: FilePath -> IO ()" which will restrict the area that can be played with to that beneath the given FilePath?

If someone does so, be aware that it is *not* trivial to write it securely.

For instance, many lazy (not in the Haskell meaning) programmers believe that the path is safe if it does not include .. but it is false (hint: ."."/foo/bar is a legal path on Unix).

That is a legal path if your Haskell program invokes (perhaps indirectly) a Unix shell. But if you can inject strings into a shell invocation then it is obviously impossible to do anything about limiting it to be weaker than the IO monad. -- Chris