coder/coderd/rbac

Authz

Package authz implements AuthoriZation for Coder.

Overview

Authorization defines what permission a subject has to perform actions to objects:

• Permission is binary: yes (allowed) or no (denied).
• Subject in this case is anything that implements interface authz.Subject.
• Action here is an enumerated list of actions, but we stick to Create, Read, Update, and Delete here.
• Object here is anything that implements authz.Object.

Permission Structure

A permission is a rule that grants or denies access for a subject to perform an action on a object. A permission is always applied at a given level:

• site level applies to all objects in a given Coder deployment.
• org level applies to all objects that have an organization owner (org_owner)
• user level applies to all objects that have an owner with the same ID as the subject.

Permissions at a higher level always override permissions at a lower level.

The effect of a permission can be:

• positive (allows)
• negative (denies)
• abstain (neither allows or denies, not applicable)

Negative permissions always override positive permissions at the same level. Both negative and positive permissions override abstain at the same level.

This can be represented by the following truth table, where Y represents positive, N represents negative, and _ represents abstain:

Action	Positive	Negative	Result
read	Y	_	Y
read	Y	N	N
read	_	_	_
read	_	N	Y

Permission Representation

Permissions are represented in string format as <sign>?<level>.<object>.<id>.<action>, where:

• negated can be either + or -. If it is omitted, sign is assumed to be +.
• level is either site, org, or user.
• object is any valid resource type.
• id is any valid UUID v4.
• action is create, read, modify, or delete.

Example Permissions

• +site.*.*.read: allowed to perform the read action against all objects of type app in a given Coder deployment.
• -user.workspace.*.create: user is not allowed to create workspaces.

Roles

A role is a set of permissions. When evaluating a role's permission to form an action, all the relevant permissions for the role are combined at each level. Permissions at a higher level override permissions at a lower level.

The following table shows the per-level role evaluation. Y indicates that the role provides positive permissions, N indicates the role provides negative permissions, and _ indicates the role does not provide positive or negative permissions. YN_ indicates that the value in the cell does not matter for the access result.

Role (example)	Site	Org	User	Result
site-admin	Y	YN_	YN_	Y
no-permission	N	YN_	YN_	N
org-admin	_	Y	YN_	Y
non-org-member	_	N	YN_	N
user	_	_	Y	Y
	_	_	N	N
unauthenticated	_	_	_	N

Testing

You can test outside of golang by using the opa cli.

Evaluation

opa eval --format=pretty 'false' -d policy.rego -i input.json

Partial Evaluation

opa eval --partial --format=pretty 'data.authz.allow' -d policy.rego --unknowns input.object.owner --unknowns input.object.org_owner --unknowns input.object.acl_user_list --unknowns input.object.acl_group_list -i input.json