Imager::Security(3) User Contributed Perl Documentation Imager::Security(3)NAMEImager::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:
· keeping your libraries up to date
· 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 v5.14.3 2012-09-28 Imager::Security(3)
