imager::security(3pm) [debian man page]

Imager::Security(3pm)					User Contributed Perl Documentation				     Imager::Security(3pm)

NAME

       Imager::Security - brief notes on security and image processing

SYNOPSIS

	 # keep abreast of security updates
	 apt-get update && apt-get upgrade
	 yum upgrade
	 pkgin update && pkgin upgrade
	 # or local equivalent

	 # limit memory use
	 use Imager;
	 # only images that use up to 10MB
	 Imager->set_file_limits(bytes => 10_000_000);

DESCRIPTION

       There's two basic security considerations when dealing with images from an unknown source:

       o   keeping your libraries up to date

       o   limiting the amount of memory used to store images

   Keeping libraries up to date
       Image file format libraries such as "libpng" or "libtiff" have relatively frequent security updates, keeping your libraries up to date is
       basic security.

       If you're using user supplied fonts, you will need to keep your font libraries up to date too.

   Limiting memory used
       With compression, and especially with pointer formats like TIFF, it's possible to store very large images in a relatively small file.

       If you're receiving image data from an untrusted source you should limit the amount of memory that Imager can allocate for a read in image
       file using the "set_file_limits()" method.

	 Imager->set_file_limits(bytes => 10_000_000);

       You may also want to limit the maximum width and height of images read from files:

	 Imager->set_file_limits(width => 10_000, height => 10_000,
				 bytes => 10_000_000);

       This has no effect on images created without a file:

	 # succeeds
	 my $image = Imager->new(xsize => 10_001, ysize => 10_001);

       You can reset to the defaults with:

	 Imager->set_file_limits(reset => 1);

AUTHOR

       Tony Cook <tonyc@cpan.org>

perl v5.14.2							    2012-06-04						     Imager::Security(3pm)

Imager::Transform(3pm)					User Contributed Perl Documentation				    Imager::Transform(3pm)

NAME

	 Imager::Transform - a library of register machine image transformations

SYNOPSIS

	 # get a list of transformations
	 my @funcs = Imager::Transform->list;
	 # create a transformation object
	 my $tran = Imager::Transform->new($name);
	 # describe it
	 print $tran->describe;
	 # a list of constant names
	 my @constants = $tran->constants;
	 # information about some of the constants
	 my @info = $tran->constants(@constants);

DESCRIPTION

       This module provides a library of transformations that use the Imager transform2() function.

       The aim is to provide a place to collect these transformations.

       At some point there might be an interface to add new functions, but there's not a whole lot of point to that.

       The interface is a little sparse as yet.

METHODS

       my @names = Imager::Transform->list
	   Returns a list of the transformations.

       my $desc = Imager::Transform->describe($name);
       my $desc = $tran->describe()
	   Describes a transformation specified either by name (as a class method) or by reference (as an instance method).

	   The class method returns undef if there is no such transformation.

       my $tran = Imager::Transform->new($name)
	   Create a new transformation object.	Returns undef if there is no such transformation.

       my @inputs = $tran->inputs;
       my $inputs = $tran->inputs;
	   Returns a list of input image descriptions, or the number of them, depending on content.

	   The list contains hash references, which current contain only one member, "desc", a description of the use of the input image.

       $tran->constants
	   Returns a list of names of constants that can be set for the transformation.

       $tran->constants($name, $name, ...)
	   Returns a hashref for each named constant, which contains the default in key "default" and a description in key "desc".

       my $out = $tran->transform(\%opts, \%constants, @imgs)
	   Perform the image transformation.

	   Returns the new image on success, or undef on failure, in which case you can use $tran->errstr to get an error message.

       $tran->errstr
	   The error message, if any from the last image transformation.

BUGS

       Needs more transformations.

SEE ALSO

       Imager(3), transform.perl

perl v5.14.2							    2011-06-06						    Imager::Transform(3pm)