Software sandboxing: The basics

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Style Pass

2025-01-12 18:00:06

Diving into the territory of software sandboxing is diving into mostly uncharted territory. The necessary pieces to implement good sandboxing in your software are scattered all-around and the pioneers haven’t yet gathered enough knowledge into an unified mappa mundi that can guide new sailors through some well understood safe routes. In this blog post I’ll offer my own share of experiences that I have acquired while working on sandboxing support for Emilua. Writing style will suffer a little because I’ll err on the side of repeating myself too much to avoid any misunderstandings.

First, let’s get some informal (but useful) definition for sandboxing just to make sure we’re on the same page. Here’s the definition that was used by Julien Tinnes and Chris Evans at Hack In The Box Malaysia 2009:

That’s a very good definition to keep the ball rolling. Let’s quickly iterate over each point individually to make them crystal clear. However keep in mind that the opinions I possess today are a little different from the opinions J. Tinnes and C. Evans had during the 2009 talk (especially around “is it okay to use superuser APIs?”), so my explanations will differ a little and guide you towards what I consider better practices for 2025.