This commit takes care of removing residual metadata
added by mat2 during the cleaning of pdf.

Mypy doesn't like some annotation in web.py,
this commits aims at pleasing it.

Mounting new, empty filesystem on /tmp makes impossible to use mat2 for manipulating files stored there. Especially it breaks running tests while creating package and using /tmp as temporary builddir which is common setup in Arch Linux:
https://aur.archlinux.org/packages/mat2/#comment-721221

georg authored 5 years ago and jvoisin committed 5 years ago

Closes #131

Due to bubblewrap's pickiness, mat2 can now be run
without a sandbox, even if bubblewrap is installed.

Apparently, abstractstaticmethod is deprecated
since python3.3.

madaidan authored 5 years ago and jvoisin committed 5 years ago

This mounts a new tmpfs on /tmp so any files residing there would be hidden
from the sandbox. Many programs store some files in there that might be useful
to an attacker.  It also drops all capabilities incase it is ever run with
extra capabilities for whatever reason.

On some machines (like mine), `/proc` has to be mounted.  Also, since
sandboxing with bubblewrap is best effort and assumes that an attacker doesn't
have control outside of the file to clean, it's safe to __try__ to enable some
bubblewrap features, and to silently fail otherwise.

This is related to the previous commit

nsids are random identifiers, usually used to ease merging
between documents, and can trivially be used for fingerprinting.