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How can I tell if a variable is tainted?

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How can I tell if a variable is tainted?

See Laundering and Detecting Tainted Data. Here's an example (which doesn't use any system calls, because the kill() is given no processes to signal):

    sub is_tainted {
        return ! eval { join('',@_), kill 0; 1; };
    }

This is not -w clean, however. There is no -w clean way to detect taintedness - take this as a hint that you should untaint all possibly-tainted data.

Source: Perl FAQ: Perl Language Issues
Copyright: Copyright (c) 1997 Tom Christiansen and Nathan Torkington.

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