Switch to a new role-based authorization framework, removing is_admin()

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.

1 files changed, 4 insertions, 34 deletions

diff --git a/plugins/mod_invites_adhoc.lua b/plugins/mod_invites_adhoc.lua
index bd6f0c2e..04c74461 100644
--- a/plugins/mod_invites_adhoc.lua
+++ b/plugins/mod_invites_adhoc.lua
@@ -2,7 +2,6 @@
 local dataforms = require "util.dataforms";
 local datetime = require "util.datetime";
 local split_jid = require "util.jid".split;
-local usermanager = require "core.usermanager";
 
 local new_adhoc = module:require("adhoc").new;
 
@@ -13,8 +12,7 @@ local allow_user_invites = module:get_option_boolean("allow_user_invites", false
 -- on the server, use the option above instead.
 local allow_contact_invites = module:get_option_boolean("allow_contact_invites", true);
 
-local allow_user_invite_roles = module:get_option_set("allow_user_invites_by_roles");
-local deny_user_invite_roles = module:get_option_set("deny_user_invites_by_roles");
+module:default_permission(allow_user_invites and "prosody:user" or "prosody:admin", ":invite-users");
 
 local invites;
 if prosody.shutdown then -- COMPAT hack to detect prosodyctl
@@ -42,36 +40,8 @@ local invite_result_form = dataforms.new({
 
 -- This is for checking if the specified JID may create invites
 -- that allow people to register accounts on this host.
-local function may_invite_new_users(jid)
-	if usermanager.get_roles then
-		local user_roles = usermanager.get_roles(jid, module.host);
-		if not user_roles then
-			-- User has no roles we can check, just return default
-			return allow_user_invites;
-		end
-
-		if user_roles["prosody:admin"] then
-			return true;
-		end
-		if allow_user_invite_roles then
-			for allowed_role in allow_user_invite_roles do
-				if user_roles[allowed_role] then
-					return true;
-				end
-			end
-		end
-		if deny_user_invite_roles then
-			for denied_role in deny_user_invite_roles do
-				if user_roles[denied_role] then
-					return false;
-				end
-			end
-		end
-	elseif usermanager.is_admin(jid, module.host) then -- COMPAT w/0.11
-		return true; -- Admins may always create invitations
-	end
-	-- No role matches, so whatever the default is
-	return allow_user_invites;
+local function may_invite_new_users(context)
+	return module:may(":invite-users", context);
 end
 
 module:depends("adhoc");
@@ -91,7 +61,7 @@ module:provides("adhoc", new_adhoc("Create new contact invite", "urn:xmpp:invite
 					};
 				};
 			end
-			local invite = invites.create_contact(username, may_invite_new_users(data.from), {
+			local invite = invites.create_contact(username, may_invite_new_users(data), {
 				source = data.from
 			});
 			--TODO: check errors