Home

Awesome

Build Fuzzing Status

OpenType Sanitizer

The OpenType Sanitizer (OTS) parses and serializes OpenType files (OTF, TTF) and WOFF and WOFF2 font files, validating them and sanitizing them as it goes.

The C library is integrated into Chromium and Firefox, and also simple command line tools to check files offline in a terminal.

The CSS font-face property is great for web typography. Having to use images in order to get the correct typeface is a great sadness; one should be able to use vectors.

However, on many platforms the system-level TrueType font renderers have never been part of the attack surface before, and putting them on the front line is a scary proposition... Especially on platforms like Windows, where it's a closed-source blob running with high privilege.

Building from source

Instructions below are for building standalone OTS utilities, if you want to use OTS as a library then the recommended way is to copy the source code and integrate it into your existing build system. Our build system does not build a shared library intentionally.

Build OTS:

$ meson setup build
$ meson compile -C build

Run ots-sanitize, for example:

$ ./build/ots-sanitize path/to/font/file

Run the tests (if you wish):

$ meson test -C build

Usage

See docs


Thanks to Alex Russell for the original idea.