I have a web app where I'm testing all input for validity. All is fine and dandy except testing file input has me perplexed. I'm testing the file input for a valid file pattern (something like \\servername\folder\etc\file.ext or c:/folder/etc/file.ext), but firefox doesn't return the entire file path, just the file name. Here's my file validation code: 
sub untaintFile{
        my $text=$_[0];
        if (defined $text && $text ne ''){
                if ($text =~ /^(\w\:([\\\/][\w\s\]+[\w\s\-\.\']*\.?[\w
+\s]*)*)$/ ||
                    $text =~ /^(\\([\\\/][\w\s\]+[\w\s\-\.\']*\.?[\w\s
+]*)*)$/   ) {
                        $text = "$1";
                } else {
                        ...code for sending me an email...
                        $text = ""; 
                }
        }
        return $text;
}

[download]
Should I just forget the pattern match and just test that there aren't any funky characters? What all should I be allowing? Does anyone have some suggestions for me?

I'm not a unix or security expert by any stretch, so i'm not exactly sure what I should consider 'safe'. Everything I've found so far on validating input is very vague and non-specific, just that good practice is to have a whitelist and not allow anything except your whitelist.

In reply to Testing file input validity in FF by Anonymous Monk

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