Minijail

The Minijail homepage and main repo is
https://android.googlesource.com/platform/external/minijail/.

There might be other copies floating around, but this is the official one!

[TOC]

What is it?

Minijail is a sandboxing and containment tool used in Chrome OS and Android.
It provides an executable that can be used to launch and sandbox other programs,
and a library that can be used by code to sandbox itself.

Getting the code

You're one git clone away from happiness.

$ git clone https://android.googlesource.com/platform/external/minijail
$ cd minijail

Releases are tagged as linux-vXX:
https://android.googlesource.com/platform/external/minijail/+refs

Building

See the HACKING.md document for more details.

Release process

See the RELEASE.md document for more details.

Contact

We've got a couple of contact points.

• minijail@chromium.org: Public user & developer mailing list.
• minijail-users@google.com: Internal Google user mailing list.
• minijail-dev@google.com: Internal Google developer mailing list.
• [crbug.com/list]: Existing bug reports & feature requests.
• [crbug.com/new]: File new bug reports & feature requests.
• [AOSP Gerrit]: Code reviews.

[crbug.com/list]: https://crbug.com/?q=component:OSSystems>Minijail
[crbug.com/new]: https://bugs.chromium.org/p/chromium/issues/entry?components=OSSystems>Minijail
[AOSP Gerrit]: https://android-review.googlesource.com/q/project:platform/external/minijail

Talks and presentations

The following talk serves as a good introduction to Minijail and how it can be used.

Video,
slides.

Example usage

The Chromium OS project has a comprehensive
sandboxing
document that is largely based on Minijail.

After you play with the simple examples below, you should check that out.

Change root to any user

# id
uid=0(root) gid=0(root) groups=0(root),128(pkcs11)
# minijail0 -u jorgelo -g 5000 /usr/bin/id
uid=72178(jorgelo) gid=5000(eng) groups=5000(eng)

Drop root while keeping some capabilities

# minijail0 -u jorgelo -c 3000 -- /bin/cat /proc/self/status
Name: cat
...
CapInh: 0000000000003000
CapPrm: 0000000000003000
CapEff: 0000000000003000
CapBnd: 0000000000003000