Re: [Expectperl-discuss] IO:tty errors

[Ken I. <fn...@ua...>]

On Wed, Nov 07, 2007 at 04:29:52PM -0500, sp...@nc... wrote:
> Hey all,
> 
> I've inherited some code that i need to fix up. There is a shell script
> that calls a perl program. The shell script is suid to a non-root user. In
> the perl script they did a set real id to effective id. With this setup
> all works, but it's a gapping security hole. the perl script uses expect
> to spawn a telnet session, and you can ctrl-] out of the telnet and
> ! to get a shell script as the suid user. I took out the set real id =
> to effective id and everything seems to work ok, but i get the following
> errors on spawing the telnet:
> 
> IO::Tty::open_slave(nonfatal): open(/dev/pts/2): Permission denied at /tools/perl/lib/IO/Pty.pm line 24.
> pty_allocate(nonfatal): open(/dev/ptmx): Permission denied at /tools/perl/lib/IO/Pty.pm line 24.
> IO::Tty::pty_allocate(nonfatal): grantpt(): Permission denied at /tools/perl/lib/IO/Pty.pm line 24.
> IO::Tty::pty_allocate(nonfatal): unlockpt(): Inappropriate ioctl for device at /tools/perl/lib/IO/Pty.pm line 24.
> 
> It makes sense to me, seems to be non-fatal, but my users will freak
> at seeing this output. Is there a quick and easy way to turn off these
> error messages?
> 
> Thanks
> -S

  $ perldoc -q warnings
  Found in /usr/share/perl/5.8/pod/perlfaq7.pod
       How do I temporarily block warnings?

       If you are running Perl 5.6.0 or better, the "use warnings" pragma allows fine
       control of what warning are produced.  See perllexwarn for more details.

           {
               no warnings;          # temporarily turn off warnings
               $a = $b + $c;         # I know these might be undef
           }

       If you have an older version of Perl, the $^W variable (documented in perlvar)
       controls runtime warnings for a block:

           {
               local $^W = 0;        # temporarily turn off warnings
               $a = $b + $c;         # I know these might be undef
           }

       Note that like all the punctuation variables, you cannot currently use my() on
       $^W, only local().

-- 
Ken Irving, fn...@ua...