PEP 752 – Implicit namespaces for package repositories

Author:: Ofek Lev <ofekmeister at gmail.com>
Sponsor:: Barry Warsaw <barry at python.org>
PEP-Delegate:: Dustin Ingram <di at python.org>
Discussions-To:: Discourse thread
Status:: Draft
Type:: Standards Track
Topic:: Packaging
Created:: 13-Aug-2024
Post-History:: 18-Aug-2024, 07-Sep-2024

Table of Contents

Abstract

This PEP specifies a way for organizations to reserve package name prefixes for future uploads.

“Namespaces are one honking great idea – let’s do more of those!” - PEP 20

Motivation

The current ecosystem lacks a way for projects with many packages to signal a verified pattern of ownership. Some examples:

Typeshed is a community effort to maintain type stubs for various packages. The stub packages they maintain mirror the package name they target and are prefixed by types-. For example, the package requests has a stub that users would depend on called types-requests.
Major cloud providers like Amazon, Google and Microsoft have a common prefix for each feature’s corresponding package [1]. For example, most of Google’s packages are prefixed by google-cloud- e.g. google-cloud-compute for using virtual machines.
Many projects [2] support a model where some packages are officially maintained and third-party developers are encouraged to participate by creating their own. For example, Datadog offers observability as a service for organizations at any scale. The Datadog Agent ships out-of-the-box with official integrations for many products, like various databases and web servers, which are distributed as Python packages that are prefixed by datadog-. There is support for creating third-party integrations which customers may run.

Such projects are uniquely vulnerable to name-squatting attacks which can ultimately result in dependency confusion.

For example, say a new product is released for which monitoring would be valuable. It would be reasonable to assume that Datadog would eventually support it as an official integration. It takes a nontrivial amount of time to deliver such an integration due to roadmap prioritization and the time required for implementation. It would be impossible to reserve the name of every potential package so in the interim an attacker may create a package that appears legitimate which would execute malicious code at runtime. Not only are users more likely to install such packages but doing so taints the perception of the entire project.

Although PEP 708 attempts to address this attack vector, it is specifically about the case of multiple repositories being considered during dependency resolution and does not offer any protection to the aforementioned use cases.

Namespacing also would drastically reduce the incidence of typosquatting because typos would have to be in the prefix itself which is normalized and likely to be a short, well-known identifier like aws-.

Rationale

Other package ecosystems have generally solved this problem by taking one of two approaches: either minimizing or maximizing backwards compatibility.

NPM has the concept of scoped packages which were introduced primarily to combat there being a dearth of available good package names (whether a real or perceived phenomenon). When a user or organization signs up they are given a scope that matches their name. For example, the package for using Google Cloud Storage is @google-cloud/storage where @google-cloud/ is the scope. Regular user accounts (non-organization) may publish unscoped packages for public use. This approach has the lowest amount of backwards compatibility because every installer and tool has to be modified to account for scopes.
NuGet has the concept of package ID prefix reservation which was introduced primarily to satisfy users wishing to know where a package came from. A package name prefix may be reserved for use by one or more owners. Every reserved package has a special indication on its page to communicate this. After reservation, any upload with a reserved prefix will fail if the user is not an owner of the prefix. Existing packages that have a prefix that is owned may continue to release as usual. This approach has the highest amount of backwards compatibility because only modifications to indices like PyPI are required and installers do not need to change.

This PEP specifies the NuGet approach of authorized reservation across a flat namespace. Any solution that requires new package syntax must be built atop the existing flat namespace and therefore implicit namespaces acquired via a reservation mechanism would be a prerequisite to such explicit namespaces.

Terminology

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

Organization: Organizations are entities that own projects and have various users associated with them.
Grant: A grant is a reservation of a namespace for a package repository.
Open Namespace: An open namespace allows for uploads from any project owner.
Restricted Namespace: A restricted namespace only allows uploads from an owner of the namespace.
Parent Namespace: A namespace’s parent refers to the namespace without the trailing hyphenated component e.g. the parent of foo-bar is foo.
Child Namespace: A namespace’s child refers to the namespace with additional trailing hyphenated components e.g. foo-bar is a valid child of foo as is foo-bar-baz.

Specification

Organizations

Any package repository that allows for the creation of projects (e.g. non-mirrors) MAY offer the concept of organizations. Organizations are entities that own projects and have various users associated with them.

Organizations MAY reserve one or more namespaces. Such reservations neither confer ownership nor grant special privileges to existing projects.

Naming

A namespace MUST be a valid project name and normalized internally e.g. foo.bar would become foo-bar.

Semantics

A namespace grant bestows ownership over the following:

A project matching the namespace itself such as the placeholder package microsoft.
Projects that start with the namespace followed by a hyphen. For example, the namespace foo would match the normalized project name foo-bar but not the project name foobar.

Package name matching acts upon the normalized namespace.

Namespaces are per-package repository and SHALL NOT be shared between repositories. For example, if PyPI has a namespace microsoft that is owned by the company Microsoft, packages starting with microsoft- that come from other non-PyPI mirror repositories do not confer the same level of trust.

Grants MUST NOT overlap. For example, if there is an existing grant for foo-bar then a new grant for foo would be forbidden. An overlap is determined by comparing the normalized proposed namespace with the normalized namespace of every existing root grant. Every comparison must append a hyphen to the end of the proposed and existing namespace. An overlap is detected when any existing namespace starts with the proposed namespace.

Uploads

If the following criteria are all true for a given upload:

The project does not yet exist.
The name matches a reserved namespace.
The project is not owned by an organization with an active grant for the namespace.

Then the upload MUST fail with a 403 HTTP status code.

Open Namespaces

The owner of a grant may choose to allow others the ability to release new projects with the associated namespace. Doing so MUST allow uploads for new projects matching the namespace from any user.

It is possible for the owner of a namespace to both make it open and allow other organizations to use the grant. In this case, the authorized organizations have no special permissions and are equivalent to an open grant without ownership.

Hidden Grants

Repositories MAY create hidden grants that are not visible to the public which prevent their namespaces from being claimed by others. Such grants MUST NOT be open and SHOULD NOT be exposed in the API.

Hidden grants are useful for repositories that wish to enforce upload restrictions without the need to expose the namespace to the public.

Repository Metadata

The JSON API version will be incremented from 1.0 to 1.1. The following API changes MUST be implemented by repositories that support this PEP. Repositories that do not support this PEP MUST NOT implement these changes so that consumers of the API are able to determine whether the repository supports this PEP.

Project Detail

The project detail response will be modified as follows.

The namespace key MUST be null if the project does not match an active namespace grant. If the project does match a namespace grant, the value MUST be a mapping with the following keys:

prefix: This is the associated normalized namespace e.g. foo-bar. If the owner of the project owns multiple matching grants then this MUST be the namespace with the most number of characters. For example, if the project name matched both foo-bar and foo-bar-baz then this key would be the latter.
authorized: This is a boolean and will be true if the project owner is an organization and is one of the current owners of the grant. This is useful for tools that wish to make a distinction between official and community packages.
open: This is a boolean indicating whether the namespace is open.

Namespace Detail

The format of this URL is /namespace/<namespace> where <namespace> is the normalized namespace. For example, the URL for the namespace foo.bar would be /namespace/foo-bar.

The response will be a mapping with the following keys:

prefix: This is the normalized version of the namespace e.g. foo-bar.
owner: This is the organization that is responsible for the namespace.
open: This is a boolean indicating whether the namespace is open.
parent: This is the parent namespace if it exists. For example, if the namespace is foo-bar and there is an active grant for foo, then this would be "foo". If there is no parent then this key will be null.
children: This is an array of any child namespaces. For example, if the namespace is foo and there are active grants for foo-bar and foo-bar-baz then this would be ["foo-bar", "foo-bar-baz"].

Grant Removal

When a reserved namespace becomes unclaimed, repositories MUST set the namespace key to null in the API.

Namespaces that were previously claimed but are now not SHOULD be eligible for claiming again by any organization.

Backwards Compatibility

There are no intrinsic concerns because there is still a flat namespace and installers need no modification. Additionally, many projects have already chosen to signal a shared purpose with a prefix like typeshed has done.

Security Implications

There is an opportunity to build on top of PEP 740 and PEP 480 so that one could prove cryptographically that a specific release came from an owner of the associated namespace. This PEP makes no effort to describe how this will happen other than that work is planned for the future.

How to Teach This

For consumers of packages we will document how metadata is exposed in the API and potentially in future note tooling that supports utilizing namespaces to provide extra security guarantees during installation.

Reference Implementation

None at this time.

Rejected Ideas

Organization Scoping

The primary motivation for this PEP is to reduce dependency confusion attacks and NPM-style scoping with an allowance of the legacy flat namespace would increase the risk. If documentation instructed a user to install bar in the namespace foo then the user must be careful to install @foo/bar and not foo-bar, or vice versa. The Python packaging ecosystem has normalization rules for names in order to maximize the ease of communication and this would be a regression.

The runtime environment of Python is also not conducive to scoping. Whereas multiple versions of the same JavaScript package may coexist, Python only allows a single global namespace. Barring major changes to the language itself, this is nearly impossible to change. Additionally, users have come to expect that the package name is usually the same as what they would import and eliminating the flat namespace would do away with that convention.

Scoping would be particularly affected by organization changes which are bound to happen over time. An organization may change their name due to internal shuffling, an acquisition, or any other reason. Whenever this happens every project they own would in effect be renamed which would cause unnecessary confusion for users, frequently.

Finally, the disruption to the community would be massive because it would require an update from every package manager, security scanner, IDE, etc. New packages released with the scoping would be incompatible with older tools and would cause confusion for users along with frustration from maintainers having to triage such complaints.

Open Issues

None at this time.

Footnotes

[2]

Some examples of projects that have many packages with a common prefix:

Django is one of the most widely used web frameworks in existence. They have the concept of reusable apps, which are commonly installed via third-party packages that implement a subset of functionality to extend Django-based websites. These packages are by convention prefixed by django- or dj-.
Project Jupyter is devoted to the development of tooling for sharing interactive documents. They support extensions which in most cases (and in all cases for officially maintained extensions) are prefixed by jupyter-.
pytest is Python’s most popular testing framework. They have the concept of plugins which may be developed by anyone and by convention are prefixed by pytest-.
MkDocs is a documentation framework based on Markdown files. They also have the concept of plugins which may be developed by anyone and are usually prefixed by mkdocs-.
Sphinx is a documentation framework popular for large technical projects such as Swift and Python itself. They have the concept of extensions which are prefixed by sphinxcontrib-, many of which are maintained within a dedicated organization.
OpenTelemetry is an open standard for observability with official packages for the core APIs and SDK with third-party packages to collect data from various sources. All packages are prefixed by opentelemetry- with child prefixes in the form opentelemetry-<component>-<name>-.
Apache Airflow is a platform to programmatically orchestrate tasks as directed acyclic graphs (DAGs). They have the concept of plugins, and also providers which are prefixed by apache-airflow-providers-.

Copyright

This document is placed in the public domain or under the CC0-1.0-Universal license, whichever is more permissive.

Source: https://github.com/python/peps/blob/main/peps/pep-0752.rst

Last modified: 2024-09-07 18:25:12 GMT