Capsicum (Unix)

Source: Wikipedia, the free encyclopedia.

Capsicum is an implementation of

DragonflyBSD in the form of kernel patches.[1] Further technical details can be found in the Ph.D. thesis [2] by Robert Watson (computer scientist)
.

The system works by chunking the normal permissions up into very small pieces. When a process enters capsicum mode, it loses all permissions normally associated with its controlling user, except "capabilities" it already has in the form of

Flags are also used to control more fine-grained access like reads and writes.[3]

CloudABI

CloudABI is an application binary interface based on capsicum. It keeps the overall capsicum permission model, but uses it to redesign a simplified environment for processes (system calls, C library, etc.) to run on, so that programs become portable to any platform supporting the ABI on the same instruction set architecture. The interface it offers is roughly POSIX minus parts that do not work with capability-based security. As of March 2020, CloudABI is natively a part of FreeBSD, and it can be run on other systems either via a Capsicum-based patch or using a non-secure system call emulator.[4][5]

As of October 2020, CloudABI has been deprecated in favor of WebAssembly System Interface for lack of interest.[4]

References

  1. ^ "Capsicum: practical capabilities for UNIX". Cambridge Computer Laboratory. Retrieved 8 April 2020.
  2. . Retrieved 1 April 2024.
  3. ^ Edge, Jake (February 22, 2012). "Capsicum: practical capabilities for UNIX". lwn.net.
  4. ^ a b "NuxiNL/cloudabi". Nuxi. 30 March 2020.
  5. ^ Brown, Neil (February 10, 2016). "CloudABI". lwn.net.

External links