Allow SAML response to set certain user attributes on creation

Allow SAML to set user attributes via additional attribute
statements in the SAML response. These allowed attributes are
currently limited to `can_create_group` and `projects_limit`.

doc/user/group/saml_sso/index.md

@@ -220,6 +220,46 @@ On subsequent visits, you should be able to go [sign in to GitLab.com with SAML]
 1. From the list of apps, click on the "GitLab.com" app (The name is set by the administrator of the identity provider).
 1. You are then signed in to GitLab.com and redirected to the group.
 
+### Configure user settings from SAML response
+
+GitLab allows setting certain user attributes based on values from the SAML response. 
+This affects users created on first sign-in via Group SAML. Existing users'
+attributes are not affected regardless of the values sent in the SAML response. 
+
+#### Supported user attributes
+
+- `can_create_group` - 'true' or 'false' to indicate whether the user can create
+  new groups. Default is `true`.
+- `projects_limit` - The total number of personal projects a user can create. 
+  A value of `0` means the user cannot create new projects in their personal 
+  namespace. Default is `10000`.
+  
+#### Example SAML response
+
+You can find SAML responses in the developer tools or console of your browser,
+in base64-encoded format. Use the base64 decoding tool of your choice to
+convert the information to XML. An example SAML response is shown here.
+
+```xml
+   <saml2:AttributeStatement>
+      <saml2:Attribute Name="email" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic">
+         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">user.email</saml2:AttributeValue>
+      </saml2:Attribute>
+      <saml2:Attribute Name="first_name" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
+         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">user.firstName</saml2:AttributeValue>
+      </saml2:Attribute>
+      <saml2:Attribute Name="last_name" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
+         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">user.lastName</saml2:AttributeValue>
+      </saml2:Attribute>
+      <saml2:Attribute Name="can_create_group" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
+         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">true</saml2:AttributeValue>
+      </saml2:Attribute>
+      <saml2:Attribute Name="projects_limit" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:unspecified">
+         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">10</saml2:AttributeValue>
+      </saml2:Attribute>
+   </saml2:AttributeStatement>
+```
+
 ### Role
 
 Starting from [GitLab 13.3](https://gitlab.com/gitlab-org/gitlab/-/issues/214523), group owners can set a 'Default membership role' other than 'Guest'. To do so, [configure the SAML SSO for the group](#configuring-gitlab). That role becomes the starting access level of all users added to the group.

ee/changelogs/unreleased/dblessing_saml_user_attributes.yml

+---
+title: Allow SAML response to set certain user attributes on creation
+merge_request: 49394
+author:
+type: added

ee/lib/gitlab/auth/group_saml/auth_hash.rb

@@ -4,9 +4,17 @@ module Gitlab
   module Auth
     module GroupSaml
       class AuthHash < Gitlab::Auth::Saml::AuthHash
+        ALLOWED_USER_ATTRIBUTES = %w(can_create_group projects_limit).freeze
+
         def groups
           Array.wrap(get_raw('groups') || get_raw('Groups'))
         end
+
+        ALLOWED_USER_ATTRIBUTES.each do |attribute|
+          define_method(attribute) do
+            Array(get_raw(attribute)).first
+          end
+        end
       end
     end
   end

ee/lib/gitlab/auth/group_saml/user.rb

@@ -51,6 +51,14 @@ module Gitlab
         def build_new_user(skip_confirmation: false)
           super.tap do |user|
             user.provisioned_by_group_id = saml_provider.group_id
+
+            # rubocop:disable GitlabSecurity/PublicSend
+            AuthHash::ALLOWED_USER_ATTRIBUTES.each do |attribute|
+              next unless value = auth_hash.public_send(attribute)
+
+              user.public_send("#{attribute}=", value)
+            end
+            # rubocop:enable GitlabSecurity/PublicSend
           end
         end
 

ee/spec/lib/gitlab/auth/group_saml/auth_hash_spec.rb

@@ -35,4 +35,42 @@ RSpec.describe Gitlab::Auth::GroupSaml::AuthHash do
       end
     end
   end
+
+  describe 'allowed user attributes methods' do
+    context 'when the attributes are presented as an array' do
+      let(:raw_info_attr) { { 'can_create_group' => %w(true), 'projects_limit' => %w(20) } }
+
+      it 'returns the proper can_create_groups value' do
+        expect(saml_auth_hash.can_create_group).to eq "true"
+      end
+
+      it 'returns the proper projects_limit value' do
+        expect(saml_auth_hash.projects_limit).to eq "20"
+      end
+    end
+
+    context 'when the attributes are presented as a string' do
+      let(:raw_info_attr) { { 'can_create_group' => 'false', 'projects_limit' => '20' } }
+
+      it 'returns the proper can_create_groups value' do
+        expect(saml_auth_hash.can_create_group).to eq "false"
+      end
+
+      it 'returns the proper projects_limit value' do
+        expect(saml_auth_hash.projects_limit).to eq "20"
+      end
+    end
+
+    context 'when the attributes are not present in the SAML response' do
+      let(:raw_info_attr) { {} }
+
+      it 'returns nil for can_create_group' do
+        expect(saml_auth_hash.can_create_group).to eq nil
+      end
+
+      it 'returns nil for can_create_groups' do
+        expect(saml_auth_hash.projects_limit).to eq nil
+      end
+    end
+  end
 end

ee/spec/lib/gitlab/auth/group_saml/user_spec.rb

@@ -7,7 +7,7 @@ RSpec.describe Gitlab::Auth::GroupSaml::User do
   let(:uid) { 1234 }
   let(:saml_provider) { create(:saml_provider) }
   let(:group) { saml_provider.group }
-  let(:auth_hash) { OmniAuth::AuthHash.new(uid: uid, provider: 'group_saml', info: info_hash) }
+  let(:auth_hash) { OmniAuth::AuthHash.new(uid: uid, provider: 'group_saml', info: info_hash, extra: { raw_info: OneLogin::RubySaml::Attributes.new }) }
   let(:info_hash) do
     {
       name: generate(:name),
@@ -82,6 +82,23 @@ RSpec.describe Gitlab::Auth::GroupSaml::User do
         it 'creates the user SAML identity' do
           expect { find_and_update }.to change { Identity.count }.by(1)
         end
+
+        context 'when user attributes are present' do
+          before do
+            auth_hash[:extra][:raw_info] =
+              OneLogin::RubySaml::Attributes.new(
+                'can_create_group' => %w(true), 'projects_limit' => %w(20)
+              )
+          end
+
+          it 'creates the user with correct can_create_group attribute' do
+            expect(find_and_update.can_create_group).to eq(true)
+          end
+
+          it 'creates the user with correct projects_limit attribute' do
+            expect(find_and_update.projects_limit).to eq(20)
+          end
+        end
       end
 
       context 'when a conflicting user already exists' do

spec/support/helpers/login_helpers.rb

@@ -138,13 +138,15 @@ module LoginHelpers
         secret: 'mock_secret'
       },
       extra: {
-        raw_info: {
+        raw_info: OneLogin::RubySaml::Attributes.new(
+          {
             info: {
               name: 'mockuser',
               email: email,
               image: 'mock_user_thumbnail_url'
             }
-        },
+          }
+        ),
         response_object: response_object
       }
     }).merge(additional_info) { |_, old_hash, new_hash| old_hash.merge(new_hash) }