oss-security - Suspicious hook-loading mechanism in hyprland

Follow @Openwall on Twitter for new release announcements and other news

[<prev] [next>] [day] [month] [year] [list]

Date: Sun, 28 Apr 2024 16:34:01 +0100
From: Sam James <sam@...too.org>
To: oss-security@...ts.openwall.com
Subject: Suspicious hook-loading mechanism in hyprland

Hi!

Someone passed along https://blog.vaxry.net/articles/2024-own-malloc to
me, and I noticed some curious bits.

hyprland seems to have committed an interesting homebrew malloc
implementation (which is fine in theory), but the reasons for it
existing & how it works are not so fine.

Fisrt, it relies on writing an object file at a predictable
path in /tmp and reading it back later.

It was needed to facilitate a trampoline which looks.. unsound. The
whole hook system looks terrifying.

Initial reading:
* https://github.com/hyprwm/Hyprland/blob/965a2e5b213eee595808bc7bff28e7df59442720/src/plugins/HookSystem.cpp#L138
* https://github.com/hyprwm/Hyprland/blob/965a2e5b213eee595808bc7bff28e7df59442720/src/plugins/HookSystem.cpp#L188

There are some primitives that may be useful even once the hook setup is
done too.

I have charitably termed the mechanism "not robust". I haven't reported
it upstream because of their hostility on other matters. I don't feel
too guilty about not having reported it given it fell out so immediately
upon inspection.

I don't plan on spending more time on this, sorry, but I felt like I had
to share it.

thanks,
sam

Download attachment "signature.asc" of type "application/pgp-signature" (378 bytes)

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.