Allow cert chains in client auth

lib/fluent/plugin_helper/socket.rb

@@ -146,8 +146,15 @@ def socket_create_tls(
           context.verify_mode = OpenSSL::SSL::VERIFY_PEER
           context.cert_store = cert_store
           context.verify_hostname = true if verify_fqdn && fqdn && context.respond_to?(:verify_hostname=)
-          context.cert = OpenSSL::X509::Certificate.new(File.read(cert_path)) if cert_path
           context.key = OpenSSL::PKey::read(File.read(private_key_path), private_key_passphrase) if private_key_path
+
+          if cert_path
+            certs = socket_certificates_from_file(cert_path)
+            context.cert = certs.shift
+            unless certs.empty?
+              context.extra_chain_cert = certs
+            end
+          end
         end
         Fluent::TLS.set_version_to_context(context, version, min_version, max_version)
 
@@ -186,6 +193,17 @@ def socket_create_tls(
         end
       end
 
+      def socket_certificates_from_file(path)
+        data = File.read(path)
+        pattern = Regexp.compile('-+BEGIN CERTIFICATE-+\r?\n(?:[^-]*\r?\n)+-+END CERTIFICATE-+\r?\n?', Regexp::MULTILINE)
+        list = []
+        data.scan(pattern) { |match| list << OpenSSL::X509::Certificate.new(match) }
+        if list.length == 0
+          log.warn "cert_path does not contain a valid certificate"
+        end
+        list
+      end
+
       def self.tls_verify_result_name(code)
         case code
         when OpenSSL::X509::V_OK then 'V_OK'

test/plugin_helper/data/cert/cert_chains/ca-cert-key.pem

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEA21in8qRqBrfYlRHr1N6eGq3d4CnKe+lTt0sGbab1670s0+h1
+lGtjWny6gLSnt5PBY36CUoFB8MtRciVG2zUhB+dAZe4Mst5dzJO6cONT/l/USbCV
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++cQ30P7KucgXvFDxQv/d+d0mu0BoYOYPP4uIbsEyE0SODQIt+LVrCmTgNzjni3op
+pFVyzT/K/Nu7fsxwbEpSySAtv8UhqSVQI89sxN81vhdAfHDR0u4lVMSqx7QXSdeS
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+LzRN4ICq18xHy8egbl93uxDcjkMxi3Wj64QZcygI9gWmDBW2hdMpEArR/grsM/FH
+DYu9KUMhm5T1KtXtV3izSVCprthdGjbKSbmR6hGw3n9Z1uP6V1rnXQ==
+-----END RSA PRIVATE KEY-----

test/plugin_helper/data/cert/cert_chains/ca-cert.pem

@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----
+MIIDPTCCAiWgAwIBAgILAJJ76Kpa6DYtsncwDQYJKoZIhvcNAQELBQAwUzELMAkG
+A1UEBhMCVVMxCzAJBgNVBAgMAkNBMRYwFAYDVQQHDA1Nb3VudGFpbiBWaWV3MR8w
+HQYDVQQDDBZjYS50ZXN0aW5nLmZsdWVudGQub3JnMCAXDTcwMDEwMTAwMDAwMFoY
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+jO31o7x4loEvaBTQbX3iP2g=
+-----END CERTIFICATE-----

test/plugin_helper/data/cert/cert_chains/cert-key.pem

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEogIBAAKCAQEAzQtGZgClcBIDKC0U1sQpznVV9HzAZANDVazrDGA8Euf8Kx4X
+dnVoE+HzwAviL4VLDPzNBLyoZ2wf3wg6D+1UAhA0DqPRCihhfJqBX0WgewakSl5a
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+OR09Qdp45tBbXtX0IjInxsnNOBzW0zTSg0xUtwIDAQABAoIBAG4N5zNIlYOZp2gh
+ClZb47SU9hXL/9euiK2rql1yKcxcB9V8yUsjqUFCvfoOZtDq0mWeKsyoFhusxU6I
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+IwvrAoGAGwg2Cq6Vs/KkiCDxoy42HVZLS/DS/iHfUTAXtekF88qwT1zHFqF1ImvO
++FEUx8IbxY1oifSQc3Jw9HYnmYqmFW1PThNG3CwyaOGgtlEFcvhHsNjLRGJSQbN2
+cUYBe2hHXii7OL8T8kIvLlCAKGA8IIfPGhsu3uUtrvMBo5c0WmQ=
+-----END RSA PRIVATE KEY-----

test/plugin_helper/data/cert/cert_chains/cert.pem

@@ -0,0 +1,40 @@
+-----BEGIN CERTIFICATE-----
+MIIDQjCCAiqgAwIBAgILANkmymLgb5e04tcwDQYJKoZIhvcNAQELBQAwVDELMAkG
+A1UEBhMCVVMxCzAJBgNVBAgMAkNBMRYwFAYDVQQHDA1Nb3VudGFpbiBWaWV3MSAw
+HgYDVQQDDBdjYTIudGVzdGluZy5mbHVlbnRkLm9yZzAgFw03MDAxMDEwMDAwMDBa
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+peWFawp53MkIBXRls66ViJsl//fPBg==
+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----
+MIIDPTCCAiWgAwIBAgIKRbRr9ZfmrY72TjANBgkqhkiG9w0BAQsFADBTMQswCQYD
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+MyrDcwH+0Aq9ZSiRaVyfCkQ=
+-----END CERTIFICATE-----

test/plugin_helper/data/cert/generate_cert.rb

@@ -7,6 +7,7 @@ module CertUtil
 
 WITHOUT_CA_DIR = './without_ca'.freeze
 WITH_CA_DIR = './with_ca'.freeze
+WITH_CERT_CHAIN_DIR = './cert_chains'.freeze
 
 CA_OPTION = {
   private_key_length: 2048,
@@ -83,5 +84,42 @@ def create_with_ca
   create_server_pair_signed_by_ca(ca_cert_pass_path, ca_key_pass_path, 'orange', cert_pass_path, cert_key_pass_path, 'apple')
 end
 
+def create_cert_pair_chained_with_root_ca(ca_cert_path, ca_key_path, ca_key_passphrase, cert_path, private_key_path, passphrase)
+  root_cert, root_key, _ = CertUtil.cert_option_generate_ca_pair_self_signed(CA_OPTION)
+  write_cert_and_key(ca_cert_path, root_cert, ca_key_path, root_key, ca_key_passphrase)
+
+  intermediate_ca_options = CA_OPTION.dup
+  intermediate_ca_options[:common_name] = 'ca2.testing.fluentd.org'
+  chain_cert, chain_key = CertUtil.cert_option_generate_pair(intermediate_ca_options, root_cert.subject)
+  chain_cert.add_extension(OpenSSL::X509::Extension.new('basicConstraints', OpenSSL::ASN1.Sequence([OpenSSL::ASN1::Boolean(true)])))
+  chain_cert.sign(root_key, 'sha256')
+
+  cert, server_key, _ = CertUtil.cert_option_generate_pair(SERVER_OPTION, chain_cert.subject)
+  cert.add_extension OpenSSL::X509::Extension.new('basicConstraints', OpenSSL::ASN1.Sequence([OpenSSL::ASN1::Boolean(false)]))
+  cert.sign(chain_key, 'sha256')
+
+  # write chained cert
+  File.open(cert_path, 'w') do |f|
+    f.write(cert.to_pem)
+    f.write(chain_cert.to_pem)
+  end
+
+  key_str = passphrase ? server_key.export(OpenSSL::Cipher.new("AES-256-CBC"), passphrase) : server_key.export
+  File.open(private_key_path, "w") { |f| f.write(key_str) }
+  File.chmod(0600, cert_path, private_key_path)
+end
+
+def create_cert_chain
+  FileUtils.mkdir_p(WITH_CERT_CHAIN_DIR)
+  ca_cert_path = File.join(WITH_CERT_CHAIN_DIR, 'ca-cert.pem')
+  ca_key_path = File.join(WITH_CERT_CHAIN_DIR, 'ca-cert-key.pem')
+
+  cert_path = File.join(WITH_CERT_CHAIN_DIR, 'cert.pem')
+  private_key_path = File.join(WITH_CERT_CHAIN_DIR, 'cert-key.pem')
+
+  create_server_pair_chained_with_root_ca(ca_cert_path, ca_key_path, nil, cert_path, private_key_path, nil)
+end
+
 create_without_ca
 create_with_ca
+create_cert_chain

test/plugin_helper/test_socket.rb

@@ -0,0 +1,131 @@
+require_relative '../helper'
+require 'fluent/plugin_helper/socket'
+require 'fluent/plugin/base'
+
+require 'socket'
+require 'openssl'
+
+class SocketHelperTest < Test::Unit::TestCase
+  PORT = unused_port
+  CERT_DIR = File.expand_path(File.dirname(__FILE__) + '/data/cert/without_ca')
+  CA_CERT_DIR = File.expand_path(File.dirname(__FILE__) + '/data/cert/with_ca')
+  CERT_CHAINS_DIR = File.expand_path(File.dirname(__FILE__) + '/data/cert/cert_chains')
+
+  class SocketHelperTestPlugin < Fluent::Plugin::TestBase
+    helpers :socket
+  end
+
+  class EchoTLSServer
+    def initialize(host = '127.0.0.1', port = PORT, cert_path: nil, private_key_path: nil, ca_path: nil)
+      server = TCPServer.open(host, port)
+      ctx = OpenSSL::SSL::SSLContext.new
+      ctx.cert = OpenSSL::X509::Certificate.new(File.open(cert_path)) if cert_path
+
+      cert_store = OpenSSL::X509::Store.new
+      cert_store.set_default_paths
+      cert_store.add_file(ca_path) if ca_path
+      ctx.cert_store = cert_store
+
+      ctx.key = OpenSSL::PKey::RSA.new(File.open(private_key_path)) if private_key_path
+      ctx.verify_mode = OpenSSL::SSL::VERIFY_PEER
+      ctx.verify_hostname = false
+
+      @server = OpenSSL::SSL::SSLServer.new(server, ctx)
+      @thread = nil
+      @r, @w = IO.pipe
+    end
+
+    def start
+      do_start
+
+      if block_given?
+        begin
+          yield
+          @thread.join(5)
+        ensure
+          stop
+        end
+      end
+    end
+
+    def stop
+      unless @w.closed?
+        @w.write('stop')
+      end
+
+      [@server, @w, @r].each do |s|
+        next if s.closed?
+        s.close
+      end
+
+      @thread.join(5)
+    end
+
+    private
+
+    def do_start
+      @thread = Thread.new(@server) do |s|
+        socks, _, _ = IO.select([s.accept, @r], nil, nil)
+
+        if socks.include?(@r)
+          break
+        end
+
+        sock = socks.first
+        buf = +''
+        loop do
+          b = sock.read_nonblock(1024, nil, exception: false)
+          if b == :wait_readable || b.nil?
+            break
+          end
+          buf << b
+        end
+
+        sock.write(buf)
+        sock.close
+      end
+    end
+  end
+
+  test 'with self-signed cert/key pair' do
+    cert_path = File.join(CERT_DIR, 'cert.pem')
+    private_key_path = File.join(CERT_DIR, 'cert-key.pem')
+
+    EchoTLSServer.new(cert_path: cert_path, private_key_path: private_key_path).start do
+      client = SocketHelperTestPlugin.new.socket_create_tls('127.0.0.1', PORT, verify_fqdn: false, cert_paths: [cert_path])
+      client.write('hello')
+      assert_equal 'hello', client.readpartial(100)
+      client.close
+    end
+  end
+
+  test 'with cert/key signed by self-signed CA' do
+    cert_path = File.join(CA_CERT_DIR, 'cert.pem')
+    private_key_path = File.join(CA_CERT_DIR, 'cert-key.pem')
+
+    ca_cert_path = File.join(CA_CERT_DIR, 'ca-cert.pem')
+
+    EchoTLSServer.new(cert_path: cert_path, private_key_path: private_key_path).start do
+      client = SocketHelperTestPlugin.new.socket_create_tls('127.0.0.1', PORT, verify_fqdn: false, cert_paths: [ca_cert_path])
+      client.write('hello')
+      assert_equal 'hello', client.readpartial(100)
+      client.close
+    end
+  end
+
+  test 'with cert/key signed by self-signed CA in server and client cert chain' do
+    cert_path = File.join(CERT_DIR, 'cert.pem')
+    private_key_path = File.join(CERT_DIR, 'cert-key.pem')
+
+    client_ca_cert_path = File.join(CERT_CHAINS_DIR, 'ca-cert.pem')
+    client_cert_path = File.join(CERT_CHAINS_DIR, 'cert.pem')
+    client_private_key_path = File.join(CERT_CHAINS_DIR, 'cert-key.pem')
+
+    EchoTLSServer.new(cert_path: cert_path, private_key_path: private_key_path, ca_path: client_ca_cert_path).start do
+      client = SocketHelperTestPlugin.new.socket_create_tls('127.0.0.1', PORT, verify_fqdn: false, cert_path: client_cert_path, private_key_path: client_private_key_path, cert_paths: [cert_path])
+      client.write('hello')
+      assert_equal 'hello', client.readpartial(100)
+      client.close
+    end
+  end
+end