Use validated URL when sending request to Gitea Importer

This change removes possibility to perform DNS Rebinding attack in Gitea
Importer.

Changelog: security

app/controllers/import/gitea_controller.rb

@@ -66,11 +66,13 @@ class Import::GiteaController < Import::GithubController
 
   override :client_options
   def client_options
-    { host: provider_url, api_version: 'v1' }
+    verified_url, provider_hostname = verify_blocked_uri
+
+    { host: verified_url.scheme == 'https' ? provider_url : verified_url.to_s, api_version: 'v1', hostname: provider_hostname }
   end
 
   def verify_blocked_uri
-    Gitlab::UrlBlocker.validate!(
+    @verified_url_and_hostname ||= Gitlab::UrlBlocker.validate!(
       provider_url,
       allow_localhost: allow_local_requests?,
       allow_local_network: allow_local_requests?,

lib/gitlab/legacy_github_import/client.rb

@@ -8,9 +8,10 @@ module Gitlab
 
       attr_reader :access_token, :host, :api_version, :wait_for_rate_limit_reset
 
-      def initialize(access_token, host: nil, api_version: 'v3', wait_for_rate_limit_reset: true)
+      def initialize(access_token, host: nil, api_version: 'v3', wait_for_rate_limit_reset: true, hostname: nil)
         @access_token = access_token
         @host = host.to_s.sub(%r{/+\z}, '')
+        @hostname = hostname
         @api_version = api_version
         @users = {}
         @wait_for_rate_limit_reset = wait_for_rate_limit_reset
@@ -28,7 +29,8 @@ module Gitlab
           # If there is no config, we're connecting to github.com and we
           # should verify ssl.
           connection_options: {
-            ssl: { verify: config ? config['verify_ssl'] : true }
+            ssl: { verify: config ? config['verify_ssl'] : true },
+            headers: { host: @hostname }.compact
           }
         )
       end

spec/controllers/import/gitea_controller_spec.rb

@@ -54,6 +54,48 @@ RSpec.describe Import::GiteaController do
           end
         end
       end
+
+      context 'when DNS Rebinding protection is enabled' do
+        let(:token) { 'gitea token' }
+
+        let(:ip_uri) { 'http://167.99.148.217' }
+        let(:uri) { 'try.gitea.io' }
+        let(:https_uri) { "https://#{uri}" }
+        let(:http_uri) { "http://#{uri}" }
+
+        before do
+          session[:gitea_access_token] = token
+
+          allow(Gitlab::UrlBlocker).to receive(:validate!).with(https_uri, anything).and_return([Addressable::URI.parse(https_uri), uri])
+          allow(Gitlab::UrlBlocker).to receive(:validate!).with(http_uri, anything).and_return([Addressable::URI.parse(ip_uri), uri])
+
+          allow(Gitlab::LegacyGithubImport::Client).to receive(:new).and_return(double('Gitlab::LegacyGithubImport::Client', repos: [], orgs: []))
+        end
+
+        context 'when provided host url is using https' do
+          let(:host_url) { https_uri }
+
+          it 'uses unchanged host url to send request to Gitea' do
+            expect(Gitlab::LegacyGithubImport::Client).to receive(:new).with(token, host: https_uri, api_version: 'v1', hostname: 'try.gitea.io')
+
+            get :status, format: :json
+
+            expect(response).to have_gitlab_http_status(:ok)
+          end
+        end
+
+        context 'when provided host url is using http' do
+          let(:host_url) { http_uri }
+
+          it 'uses changed host url to send request to Gitea' do
+            expect(Gitlab::LegacyGithubImport::Client).to receive(:new).with(token, host: 'http://167.99.148.217', api_version: 'v1', hostname: 'try.gitea.io')
+
+            get :status, format: :json
+
+            expect(response).to have_gitlab_http_status(:ok)
+          end
+        end
+      end
     end
   end
 

spec/lib/gitlab/legacy_github_import/client_spec.rb

@@ -86,6 +86,15 @@ RSpec.describe Gitlab::LegacyGithubImport::Client do
       it 'builds a endpoint with the given options' do
         expect(client.api.api_endpoint).to eq 'https://try.gitea.io/api/v3/'
       end
+
+      context 'and hostname' do
+        subject(:client) { described_class.new(token, host: 'https://167.99.148.217/', api_version: 'v1', hostname: 'try.gitea.io') }
+
+        it 'builds a endpoint with the given options' do
+          expect(client.api.connection_options.dig(:headers, :host)).to eq 'try.gitea.io'
+          expect(client.api.api_endpoint).to eq 'https://167.99.148.217/api/v1/'
+        end
+      end
     end
   end