perl -wTe 'use Scalar::Util qw( tainted ); $x = $ARGV[0]; print "taint
+ed!\n" if tainted( $x ); $x = pack "a*", $x; print "No longer tainted
+!\n" unless tainted ($x); eval( $x ); ' 'print "hello, world\n";'

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The above code creates a file using Perl 5.10, but complains and dies under 5.8.8 as it probably should. I've submitted a perlbug thanking ambrus and tye in the report.

Thanks to ambrus for pointing it out and tye for suggesting Scalar::Util to test the taintedness of a value.

The docs say to use a regular expression (or to make the data the key of a hash) in order to untaint it. There's no mention of pack().

ambrus asked in the CB if that is a bug. I think it probably is.

In reply to pack() untaints data : bug or undocumented Perl 5.10 feature? by mr_mischief

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