Too late for "-T" option
      (X) The #! line (or local equivalent) in a Perl script contains 
+the
      -T option, but Perl was not invoked with -T in its command line.
      This is an error because, by the time Perl discovers a -T in a
      script, it's too late to properly taint everything from the
      environment. So Perl gives up.

      If the Perl script is being executed as a command using the #!
      mechanism (or its local equivalent), this error can usually be f
+ixed
      by editing the #! line so that the -T option is a part of Perl's
      first argument: e.g. change "perl -n -T" to "perl -T -n".

      If the Perl script is being executed as "perl scriptname", then 
+the
      -T option must appear on the command line: "perl -T scriptname".
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That is exactly what I was looking for! Bookmarked it for future use. Thanks.

Well, you will get this error message if the shebang line is actually no more used as such:

$ cat example
#!/usr/bin/perl -T
print "hello\n";
$ chmod u+x example; example
hello
$ perl example
Too late for "-T" option at ol line 1.
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I can only guess what this means: When you start a script with `perl scriptname`, perl starts up and might enable the "taint mode" or not and _then_ takes your script. Because it's clever it examines the input file for a shebang line and tries to get as much as possible out of it, but '-T' can no more be evaluated. If you start your script as `scriptname`, the shebang is _really_ the perl-call and so perl gets all startup-information from that line. In CGI environment the shebang is also the startup-information-source for perl, so it's not "too" late there.

In some close reading of the OpenBSD kernel (for example) you'll notice that the shebang line is handled directly by the underlying exec() call. This is partly where the old thing about interpreted scripts under SUID had issues - #1 the OS reads the file, #2 interpretes the shebang, #3 executes the interpretor, #4 the interpretor reads from the already open file and executes. The attack was to replace the OK code with bad code somewhere between step #1 and step #4.

I think the fix was to prevent the non-SUID user from getting access to the SUID's user's about-to-be-passed filehandles though I don't really recall.

Wow. I've never posted here before. That was fast. All the replies helped me understand things better. Thanks.

In command mode, call the script with  perl -T xxxxxx.pl

how are you testing in unix? if by the command line, you have to specify the -T on the command line as well:

> perl -T /path/to/script.pl
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-- Dan

It's too bad that you can't remember where you read it. Otherwise, we could correct that information. Taint mode does indeed work on the Windows platform. You just have to make sure that the initial mapping actually used to launch perl has the -T (or -t, I suppose) flag.