Some of the OAuth stuff highlights a small need to retrieve a list of
roles somehow. Handy if you ever need a role selector in adhoc or
something.
Unless there's some O(n) thing we were avoiding?
These changes to the API (hopefully the last) introduce a cleaner separation
between the user's primary (default) role, and their secondary (optional)
roles.
To keep the code sane and reduce complexity, a data migration is needed for
people using stored roles in 0.12. This can be performed with
prosodyctl mod_authz_internal migrate <host>
Goal: Introduce role-auth with minimal disruption
is_admin() is unsafe in a system with per-session permissions, so it has been
deprecated.
Roll-out approach:
1) First, log a warning when is_admin() is used. It should continue to
function normally, backed by the new role API. Nothing is really using
per-session authz yet, so there is minimal security concern.
The 'strict_deprecate_is_admin' global setting can be set to 'true' to
force a hard failure of is_admin() attempts (it will log an error and
always return false).
2) In some time (at least 1 week), but possibly longer depending on the number
of affected deployments: switch 'strict_deprecate_is_admin' to 'true' by
default. It can still be disabled for systems that need it.
3) Further in the future, before the next release, the option will be removed
and is_admin() will be permanently disabled.
Rationale:
- Removes a bunch of code!
- We don't have many cases where an actor is not bound to one of our hosts
- A notable exception is the admin shell, but if we ever attempt to lock those
sessions down, there is a load of other work that also has to be done. And
it's not clear if we would need a global authz provider for that anyway.
- Removes an extra edge case from the necessary mental model for operators
- Sessions that aren't bound to a host generally are anonymous or have an
alternative auth model (such as by IP addres).
- With the encapsulation now provided by util.roles, ad-hoc "detached roles"
can still be created anyway by code that needs them.
This commit was too awkward to split (hg record didn't like it), so:
- Switch to the new util.roles lib to provide a consistent representation of
a role object.
- Change API method from get_role_info() to get_role_by_name() (touches
sessionmanager and usermanager)
- Change get_roles() to get_user_roles(), take a username instead of a JID
This is more consistent with all other usermanager API methods.
- Support configuration of custom roles and permissions via the config file
(to be documented).
This is useful for a number of things. For example, listing users that need to
rotate their passwords after some event. It also provides a safer way for code
to determine that a user password has changed without needing to set a handler
for the password change event (which is a more fragile approach).
We began moving away from simple "is this user an admin?" permission checks
before 0.12, with the introduction of mod_authz_internal and the ability to
dynamically change the roles of individual users.
The approach in 0.12 still had various limitations however, and apart from
the introduction of roles other than "admin" and the ability to pull that info
from storage, not much actually changed.
This new framework shakes things up a lot, though aims to maintain the same
functionality and behaviour on the surface for a default Prosody
configuration. That is, if you don't take advantage of any of the new
features, you shouldn't notice any change.
The biggest change visible to developers is that usermanager.is_admin() (and
the auth provider is_admin() method) have been removed. Gone. Completely.
Permission checks should now be performed using a new module API method:
module:may(action_name, context)
This method accepts an action name, followed by either a JID (string) or
(preferably) a table containing 'origin'/'session' and 'stanza' fields (e.g.
the standard object passed to most events). It will return true if the action
should be permitted, or false/nil otherwise.
Modules should no longer perform permission checks based on the role name.
E.g. a lot of code previously checked if the user's role was prosody:admin
before permitting some action. Since many roles might now exist with similar
permissions, and the permissions of prosody:admin may be redefined
dynamically, it is no longer suitable to use this method for permission
checks. Use module:may().
If you start an action name with ':' (recommended) then the current module's
name will automatically be used as a prefix.
To define a new permission, use the new module API:
module:default_permission(role_name, action_name)
module:default_permissions(role_name, { action_name[, action_name...] })
This grants the specified role permission to execute the named action(s) by
default. This may be overridden via other mechanisms external to your module.
The built-in roles that developers should use are:
- prosody:user (normal user)
- prosody:admin (host admin)
- prosody:operator (global admin)
The new prosody:operator role is intended for server-wide actions (such as
shutting down Prosody).
Finally, all usage of is_admin() in modules has been fixed by this commit.
Some of these changes were trickier than others, but no change is expected to
break existing deployments.
EXCEPT: mod_auth_ldap no longer supports the ldap_admin_filter option. It's
very possible nobody is using this, but if someone is then we can later update
it to pull roles from LDAP somehow.
The default config was updated in this way long ago, but if no option was
present in the config, Prosody would load internal_plain.
This change can result in changes (for the better) for people using very old
configuration files lacking an 'authentication' setting.
Note: Removes the ability for mod_auth_* providers to determine user admin status. Such
modules will need to have their is_admin methods ported to be a mod_authz_* provider.
