[master] Fix CRLF issue in UrlValidator

changelogs/unreleased/security-fj-crlf-injection.yml

+---
+title: Fix CRLF vulnerability in Project hooks
+merge_request:
+author:
+type: security

lib/gitlab/url_blocker.rb

@@ -10,11 +10,8 @@ module Gitlab
       def validate!(url, allow_localhost: false, allow_local_network: true, enforce_user: false, ports: [], protocols: [])
         return true if url.nil?
 
-        begin
-          uri = Addressable::URI.parse(url)
-        rescue Addressable::URI::InvalidURIError
-          raise BlockedUrlError, "URI is invalid"
-        end
+        # Param url can be a string, URI or Addressable::URI
+        uri = parse_url(url)
 
         # Allow imports from the GitLab instance itself but only from the configured ports
         return true if internal?(uri)
@@ -49,6 +46,18 @@ module Gitlab
 
       private
 
+      def parse_url(url)
+        raise Addressable::URI::InvalidURIError if multiline?(url)
+
+        Addressable::URI.parse(url)
+      rescue Addressable::URI::InvalidURIError, URI::InvalidURIError
+        raise BlockedUrlError, 'URI is invalid'
+      end
+
+      def multiline?(url)
+        CGI.unescape(url.to_s) =~ /\n|\r/
+      end
+
       def validate_port!(port, ports)
         return if port.blank?
         # Only ports under 1024 are restricted

spec/models/project_spec.rb

@@ -234,6 +234,7 @@ describe Project do
       end
     end
 
+    describe 'import_url' do
       it 'does not allow an invalid URI as import_url' do
         project = build(:project, import_url: 'invalid://')
 
@@ -306,6 +307,22 @@ describe Project do
         expect(project.errors[:import_url].first).to include('Username needs to start with an alphanumeric character')
       end
 
+      include_context 'invalid urls'
+
+      it 'does not allow urls with CR or LF characters' do
+        project = build(:project)
+
+        aggregate_failures do
+          urls_with_CRLF.each do |url|
+            project.import_url = url
+
+            expect(project).not_to be_valid
+            expect(project.errors.full_messages.first).to match(/is blocked: URI is invalid/)
+          end
+        end
+      end
+    end
+
     describe 'project pending deletion' do
       let!(:project_pending_deletion) do
         create(:project,

spec/support/shared_contexts/url_shared_context.rb

+shared_context 'invalid urls' do
+  let(:urls_with_CRLF) do
+    ["http://127.0.0.1:333/pa\rth",
+     "http://127.0.0.1:333/pa\nth",
+     "http://127.0a.0.1:333/pa\r\nth",
+     "http://127.0.0.1:333/path?param=foo\r\nbar",
+     "http://127.0.0.1:333/path?param=foo\rbar",
+     "http://127.0.0.1:333/path?param=foo\nbar",
+     "http://127.0.0.1:333/pa%0dth",
+     "http://127.0.0.1:333/pa%0ath",
+     "http://127.0a.0.1:333/pa%0d%0th",
+     "http://127.0.0.1:333/pa%0D%0Ath",
+     "http://127.0.0.1:333/path?param=foo%0Abar",
+     "http://127.0.0.1:333/path?param=foo%0Dbar",
+     "http://127.0.0.1:333/path?param=foo%0D%0Abar"]
+  end
+end

spec/validators/url_validator_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe UrlValidator do
@@ -6,6 +8,30 @@ describe UrlValidator do
 
   include_examples 'url validator examples', described_class::DEFAULT_PROTOCOLS
 
+  describe 'validations' do
+    include_context 'invalid urls'
+
+    let(:validator) { described_class.new(attributes: [:link_url]) }
+
+    it 'returns error when url is nil' do
+      expect(validator.validate_each(badge, :link_url, nil)).to be_nil
+      expect(badge.errors.first[1]).to eq 'must be a valid URL'
+    end
+
+    it 'returns error when url is empty' do
+      expect(validator.validate_each(badge, :link_url, '')).to be_nil
+      expect(badge.errors.first[1]).to eq 'must be a valid URL'
+    end
+
+    it 'does not allow urls with CR or LF characters' do
+      aggregate_failures do
+        urls_with_CRLF.each do |url|
+          expect(validator.validate_each(badge, :link_url, url)[0]).to eq 'is blocked: URI is invalid'
+        end
+      end
+    end
+  end
+
   context 'by default' do
     let(:validator) { described_class.new(attributes: [:link_url]) }