1.3 KiB
Implementation notes
Symlink attacks
MAT2 output predictable filenames (like yourfile.jpg.cleaned). This may lead to symlink attack. Please check if you OS prevent against them
Archives handling
MAT2 doesn't support archives yet, because we haven't found an usable way to ask the user what to do when a non-supported files are encountered.
PDF handling
MAT was doing some kind of rendering for PDF files, on a cairo surface, then printed it to a file. This kept the text selectable, but unfortunately, it didn't remove any deep metadata, like the ones in embedded pictures. This was on of the reason MAT was abandoned: the absence of satisfying solution to handle PDF. But apparently, people are ok with pdf redact tools, that simply transform the PDF into images. So this is what's MAT2 is doing too.
Of course, it would be possible to detect images in PDf file, and process them with MAT2, but since a PDF can contain a lot of things, like images, videos, javascript, pdf, blobs, … this is the easiest and safest way to clean them.
Images handling
When possible, images are handled like PDF: rendered on a surface, then saved to the filesystem. This ensures that every metadata is removed.