Glad to be of help. =)

Well a few things that I noticed is that you need to modify the second condition...

No you don't. Lets have a look at the code again:

# in case of success: return a 'true' value   (1 or a useful value)
# in case of error:   return a 'false' value  (0 or undef)
sub verify_port {
  my $value = shift;

  # user provided input should be viewed as toxic - do not
  # trust until proven to contain a sane value
  if (defined $value and $value =~ /\A (\d+) \z/xms) {
    my $port = $1;

    if ($MIN_TCP_PORT <= $port and $port <= $MAX_TCP_PORT) {
      return 1;  # or TRUE or $port
    }
  }

  return 0;  # or FALSE or undef
}

[download]

As stated in the function's comment, the function is supposed to return a 'true' value if everything is alright and a 'false' value in case it isn't. (You did it the other way round - return FALSE if the port is fine and TRUE if it isn't.) So what I am doing is to make sure the provided port is defined, an integer and _inside_ the allowed port range. Only then '1' (or TRUE or $port) is returned.

In all other cases (e.g. value is undefined or outside the allowed port range) then the function will return '0' (or FALSE or undef)

Question, why are you assigning the $value to a new value $port = $1. Is there a specific reason?

It is just an additional safeguard to make sure I perform the second check against a validated value. Additionally if you choose to return $port instead of 1 or TRUE then you can use the function to untaint your external / user-provided input.

http://perldoc.perl.org/perlsec.html#Taint-mode
http://www.webreference.com/programming/perl/taint/index.html

In reply to Re^7: RFC: Net::SNTP::Client v1 by Monk::Thomas
in thread RFC: Net::SNTP::Client v1 by thanos1983

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