https://github.com/evancarroll/container-perl

Run perl in a container with podman
https://github.com/evancarroll/container-perl

container perl perl5 podman secure

Last synced: 2 months ago
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Run perl in a container with podman

• Host: GitHub
• URL: https://github.com/evancarroll/container-perl
• Owner: EvanCarroll
• Created: 2022-06-24T20:20:06.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-06-27T03:11:18.000Z (over 2 years ago)
• Last Synced: 2024-10-12T11:42:33.279Z (2 months ago)
• Topics: container, perl, perl5, podman, secure
• Language: Perl
• Homepage:
• Size: 8.79 KB
• Stars: 7
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
`container_perl`

====

This is a wrapper around perl to recreate the environment in `podman`. What it

does is,

* Get the version of perl on the host, map it to an OCI image name.

* Get the current `@INC` on the host.

* Prepare a container that maps the host's `@INC` directories to the container

* Clobbers the `@INC` of the container perl with just the mapped dirs from the

	host using [`libreplace`](https://metacpan.org/pod/libreplace).

* `exec`'s a copy of a Perl using Podman in a container as above.

Security

---

The goal of this program is to allow arbitrary code executation of perl within

the context of a secure user-namespace.

Example

====

```sh

container-perl -E 'say "Hello World"';

container-perl ./testfile.pl

```

For the purpose of the demo, [`testfile.pl`](./testfile.pl) outputs the UID. This will change when

run inside and outside of `container-perl` because user namespaces allow 

perl running in the namespace to think it's root. While invoking this file with

regular perl will show it as the UID of the user.

Installation

====

Container perl requires,

* [usernamespaces enabled](https://unix.stackexchange.com/a/602409/3285)

* `podman` installed

* Perl 5's [`libreplace`](https://github.com/EvanCarroll/perl5-libreplace) installed

Notes

====

Currently, all the deps directory outside the directory are mounted read-only.

The working directory is mounted read-write.

Inspiration

----

The source of inspiration of this was [Brian Scannell's talk in The Perl

Conference 2022 on IDE and checking Perl

syntax](https://tprc2022.sched.com/event/11nfS/the-perl-navigator-code-intelligence-for-any-editor).

In that talk Brian puts forward two methods of dealing with the insecurity of

checking perl syntax, with `perl -c`

1. Trusting a project. Trust in this context would require you to audit the

	 code before testing the syntax. I doubt anyone will do this.

2. Executing the syntax checking on a remote machine, over SSH.

This approach uses podman to create a ephemeral container to syntax check Perl.