Imager::Security - brief notes on security and image processing
# 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);
There's two basic security considerations when dealing with images from an unknown source:
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.
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);
Tony Cook <tonyc@cpan.org>