Abigail

True, but then, as I said, we're still screwed since taint doesn't force you to get the cleaning right

Look, it's a moot point (who the hell turns off taint checking?), but a valid one. Turning off taint checking on a production script shouldn't make any difference

Consider - you develop a script, and when you test with taint on, the following generates a warning:

foreach(@ARGV){
  `$_`;
}
[download]

So you correct it:

foreach(@ARGV){
  /(\w*)/;
  $foo = `ls -l $1`;
}
[download]

Is this going to be any less secure for running without taint once you've got it to run with taint?

foreach(@ARGV){
  /(.*)/;
  $foo = `$1`;
}
[download]

and is this going to be any less insecure for running with taint?
Tom Melly, tom@tomandlu.co.uk

Let's say, you have the following program:

#!/usr/bin/perl -T

use strict;
use warnings;

my $file = shift;

open my $fh => $file or die $!;
while (<$fh>) {print}
close $fh;

__END__
[download]

A fairly trivial one. Takes only one parameter. You test it with a million files. It all works fine. You remove the '-T' and put it in production, where it's going to be run suid or called by a CGI program, or whatever.

Then some joker passes "> /some/important/file" as argument. With "-T", perl would not have wiped the content of the file. Without, it will.

Abigail