Painless Linux sandboxing API

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Albert S 51844ea3ab bpf: Deny x32 system calls for now The arch field is the same for x86_64 and x32, thus checking it is not enough. Simply using x32 system calls would allow a bypass. Thus, we must check whether the system call number is in __X32_SYSCALL_BIT. This is of course a lazy solution, we could also add the same system call number + _X32_SYSCALL_BIT to our black/whitelists. For now however, this however will do.		2021-08-12 12:25:12 +02:00
Makefile	Start implementing tests	2021-06-05 20:11:07 +02:00
qssb.h	bpf: Deny x32 system calls for now	2021-08-12 12:25:12 +02:00
README.md	update README	2021-06-08 22:04:26 +02:00
test.c	bpf: Deny x32 system calls for now	2021-08-12 12:25:12 +02:00
test.sh	test: Log output of individual tests	2021-06-06 09:27:45 +02:00

README.md

qssb.h (quite simple sandbox)

qssb.h is a simple header-only library that provides an interface to sandbox processes on Linux. Using Seccomp and Linux Namespaces for that purpose requires some knowledge of annoying details which this library aims to abstract away as much as possible, when reasonable. Hence, the goal is to provide a convenient way for processes to restrict themselves in order to mitigate the effect of exploits. Currently, it utilizes technologies like Seccomp, Namespaces and Landlock to this end.

Status

No release yet, expiremental, API is unstable, builds will break on updates of this library.

Features

Systemcall filtering (using seccomp-bpf)
restricting file system access (using Landlock and/or Namespaces)
dropping privileges
isolating the application from the network, etc.

Requirements

Kernel >=3.17

sys/capabilities.h header. Depending on your distribution, libcap might be needed for this.

While mostly transparent to users of this API, kernel >= 5.13 is required to take advantage of Landlock.

FAQ

Does the process need to be priviliged to utilize the library?

No.

It doesn't work on Debian!

You can thank a Debian-specific kernel patch for that. In the future, the library may check against that. Execute echo 1 > /proc/sys/kernel/unprivileged_userns_clone to disable that patch for now.

Examples

qswiki: https://gitea.quitesimple.org/crtxcr/qswiki
cgit sandboxed: https://gitea.quitesimple.org/crtxcr/cgitsb
qpdfviewsb sandboxed (quick and dirty): https://gitea.quitesimple.org/crtxcr/qpdfviewsb

Contributing

Contributions are very welcome. Options:

Pull-Request on github
Mail to qssb at quitesimple.org with instructions on where to pull the changes from.
Mailing a classic patch/diff to the same address.

License

ISC