Feat: ssl_supported_protocols (TLSv1.3) (#47)

* requires latest LS 8.1 due jruby-openssl pinning
  (jruby-openssl >= 0.12.2 dependency needed)

+ Refactor: review/normalize (exception) logging

+ a close operation should release client sockets

Co-authored-by: João Duarte <jsvd@users.noreply.github.com>

Author: kares

.travis.yml

@@ -1,2 +1,8 @@
 import:
-- logstash-plugins/.ci:travis/travis.yml@1.x
+  - logstash-plugins/.ci:travis/defaults.yml@1.x
+  - logstash-plugins/.ci:travis/exec.yml@1.x
+
+env:
+  jobs:
+    - ELASTIC_STACK_VERSION=8.x
+    - SNAPSHOT=true ELASTIC_STACK_VERSION=8.x

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 6.1.0
+  - Feat: ssl_supported_protocols (TLSv1.3) [#47](https://github.com/logstash-plugins/logstash-output-tcp/pull/47)
+  - Fix: close server and client sockets on plugin close
+
 ## 6.0.2
   - Fix: unable to start with password protected key [#45](https://github.com/logstash-plugins/logstash-output-tcp/pull/45)
 

docs/index.asciidoc

@@ -45,6 +45,7 @@ This plugin supports the following configuration options plus the <<plugins-{typ
 | <<plugins-{type}s-{plugin}-ssl_enable>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-ssl_key>> |a valid filesystem path|No
 | <<plugins-{type}s-{plugin}-ssl_key_passphrase>> |<<password,password>>|No
+| <<plugins-{type}s-{plugin}-ssl_supported_protocols>> |<<string,string>>|No
 | <<plugins-{type}s-{plugin}-ssl_verify>> |<<boolean,boolean>>|No
 |=======================================================================
 
@@ -130,6 +131,20 @@ SSL key path
 
 SSL key passphrase
 
+[id="plugins-{type}s-{plugin}-ssl_supported_protocols"]
+===== `ssl_supported_protocols`
+
+  * Value type is <<string,string>>
+  * Allowed values are: `'TLSv1.1'`, `'TLSv1.2'`, `'TLSv1.3'`
+  * Default depends on the JDK being used. With up-to-date Logstash, the default is `['TLSv1.2', 'TLSv1.3']`.
+    `'TLSv1.1'` is not considered secure and is only provided for legacy applications.
+
+List of allowed SSL/TLS versions to use when establishing a secure connection.
+
+NOTE: If you configure the plugin to use `'TLSv1.1'` on any recent JVM, such as the one packaged with Logstash,
+the protocol is disabled by default and needs to be enabled manually by changing `jdk.tls.disabledAlgorithms` in
+the *$JDK_HOME/conf/security/java.security* configuration file. That is, `TLSv1.1` needs to be removed from the list.
+
 [id="plugins-{type}s-{plugin}-ssl_verify"]
 ===== `ssl_verify` 
 

lib/logstash/outputs/tcp.rb

@@ -51,38 +51,43 @@ class LogStash::Outputs::Tcp < LogStash::Outputs::Base
   # SSL key passphrase
   config :ssl_key_passphrase, :validate => :password, :default => nil
 
+  # NOTE: the default setting [] uses SSL engine defaults
+  config :ssl_supported_protocols, :validate => ['TLSv1.1', 'TLSv1.2', 'TLSv1.3'], :default => [], :list => true
+
   class Client
-    public
+
     def initialize(socket, logger)
       @socket = socket
       @logger = logger
       @queue  = Queue.new
     end
 
-    public
     def run
       loop do
         begin
           @socket.write(@queue.pop)
         rescue => e
-          @logger.warn("tcp output exception", :socket => @socket,
-                       :exception => e)
+          log_warn 'socket write failed:', e, socket: (@socket ? @socket.to_s : nil)
           break
         end
       end
     end # def run
 
-    public
     def write(msg)
       @queue.push(msg)
     end # def write
+
+    def close
+      @socket.close
+    rescue => e
+      log_warn 'socket close failed:', e, socket: (@socket ? @socket.to_s : nil)
+    end
   end # class Client
 
-  private
   def setup_ssl
     require "openssl"
 
-    @ssl_context = OpenSSL::SSL::SSLContext.new
+    @ssl_context = new_ssl_context
     if @ssl_cert
       @ssl_context.cert = OpenSSL::X509::Certificate.new(File.read(@ssl_cert))
       if @ssl_key
@@ -104,50 +109,74 @@ def setup_ssl
       @ssl_context.cert_store = @cert_store
       @ssl_context.verify_mode = OpenSSL::SSL::VERIFY_PEER|OpenSSL::SSL::VERIFY_FAIL_IF_NO_PEER_CERT
     end
-  end # def setup_ssl
 
-  public
+    @ssl_context.min_version = :TLS1_1 # not strictly required - JVM should have disabled TLSv1
+    if ssl_supported_protocols.any?
+      disabled_protocols = ['TLSv1.1', 'TLSv1.2', 'TLSv1.3'] - ssl_supported_protocols
+      unless OpenSSL::SSL.const_defined? :OP_NO_TLSv1_3 # work-around JRuby-OpenSSL bug - missing constant
+        @ssl_context.max_version = :TLS1_2 if disabled_protocols.delete('TLSv1.3')
+      end
+      # mapping 'TLSv1.2' -> OpenSSL::SSL::OP_NO_TLSv1_2
+      disabled_protocols.map! { |v| OpenSSL::SSL.const_get "OP_NO_#{v.sub('.', '_')}" }
+      @ssl_context.options = disabled_protocols.reduce(@ssl_context.options, :|)
+    end
+    @ssl_context
+  end
+  private :setup_ssl
+
+  # @note to be able to hook up into #ssl_context from tests
+  def new_ssl_context
+    OpenSSL::SSL::SSLContext.new
+  end
+  private :new_ssl_context
+
+  # @overload Base#register
   def register
     require "socket"
     require "stud/try"
-    if @ssl_enable
-      setup_ssl
-    end # @ssl_enable
+    @closed = Concurrent::AtomicBoolean.new(false)
+    setup_ssl if @ssl_enable
 
     if server?
       @logger.info("Starting tcp output listener", :address => "#{@host}:#{@port}")
       begin
         @server_socket = TCPServer.new(@host, @port)
       rescue Errno::EADDRINUSE
-        @logger.error("Could not start TCP server: Address in use",
-                      :host => @host, :port => @port)
+        @logger.error("Could not start tcp server: Address in use", host: @host, port: @port)
         raise
       end
       if @ssl_enable
         @server_socket = OpenSSL::SSL::SSLServer.new(@server_socket, @ssl_context)
       end # @ssl_enable
-      @client_threads = []
+      @client_threads = Concurrent::Array.new
 
       @accept_thread = Thread.new(@server_socket) do |server_socket|
+        LogStash::Util.set_thread_name("[#{pipeline_id}]|output|tcp|server_accept")
         loop do
-          Thread.start(server_socket.accept) do |client_socket|
+          break if @closed.value
+          client_socket = server_socket.accept_nonblock exception: false
+          if client_socket == :wait_readable
+            IO.select [ server_socket ]
+            next
+          end
+          Thread.start(client_socket) do |client_socket|
             # monkeypatch a 'peer' method onto the socket.
             client_socket.instance_eval { class << self; include ::LogStash::Util::SocketPeer end }
-            @logger.debug("Accepted connection", :client => client_socket.peer,
-                          :server => "#{@host}:#{@port}")
+            @logger.debug("accepted connection", client: client_socket.peer, server: "#{@host}:#{@port}")
             client = Client.new(client_socket, @logger)
             Thread.current[:client] = client
+            LogStash::Util.set_thread_name("[#{pipeline_id}]|output|tcp|client_socket-#{@client_threads.size}")
             @client_threads << Thread.current
-            client.run
+            client.run unless @closed.value
           end
         end
       end
 
       @codec.on_event do |event, payload|
+        @client_threads.select!(&:alive?)
         @client_threads.each do |client_thread|
           client_thread[:client].write(payload)
         end
-        @client_threads.reject! {|t| !t.alive? }
       end
     else
       client_socket = nil
@@ -163,18 +192,35 @@ def register
           # Now send the payload
           client_socket.syswrite(payload) if w.any?
         rescue => e
-          @logger.warn("tcp output exception", :host => @host, :port => @port,
-                       :exception => e, :backtrace => e.backtrace)
+          log_warn "client socket failed:", e, host: @host, port: @port, socket: (client_socket ? client_socket.to_s : nil)
           client_socket.close rescue nil
           client_socket = nil
           sleep @reconnect_interval
           retry
         end
       end
     end
-  end # def register
+  end
+
+  # @overload Base#receive
+  def receive(event)
+    @codec.encode(event)
+  end
+
+  # @overload Base#close
+  def close
+    @closed.make_true
+    @server_socket.close rescue nil if @server_socket
+
+    return unless @client_threads
+    @client_threads.each do |thread|
+      client = thread[:client]
+      client.close rescue nil if client
+    end
+  end
 
   private
+
   def connect
     begin
       client_socket = TCPSocket.new(@host, @port)
@@ -183,29 +229,40 @@ def connect
         begin
           client_socket.connect
         rescue OpenSSL::SSL::SSLError => ssle
-          @logger.error("SSL Error", :exception => ssle, :backtrace => ssle.backtrace)
+          log_error 'connect ssl failure:', ssle, backtrace: false
           # NOTE(mrichar1): Hack to prevent hammering peer
           sleep(5)
           raise
         end
       end
       client_socket.instance_eval { class << self; include ::LogStash::Util::SocketPeer end }
-      @logger.debug("Opened connection", :client => "#{client_socket.peer}")
+      @logger.debug("opened connection", :client => client_socket.peer)
       return client_socket
-    rescue StandardError => e
-      @logger.error("Failed to connect: #{e.message}", :exception => e.class, :backtrace => e.backtrace)
+    rescue => e
+      log_error 'failed to connect:', e
       sleep @reconnect_interval
       retry
     end
   end # def connect
 
-  private
   def server?
     @mode == "server"
   end # def server?
 
-  public
-  def receive(event)
-    @codec.encode(event)
-  end # def receive
+  def pipeline_id
+    execution_context.pipeline_id || 'main'
+  end
+
+  def log_warn(msg, e, backtrace: @logger.debug?, **details)
+    details = details.merge message: e.message, exception: e.class
+    details[:backtrace] = e.backtrace if backtrace
+    @logger.warn(msg, details)
+  end
+
+  def log_error(msg, e, backtrace: @logger.info?, **details)
+    details = details.merge message: e.message, exception: e.class
+    details[:backtrace] = e.backtrace if backtrace
+    @logger.error(msg, details)
+  end
+
 end # class LogStash::Outputs::Tcp

logstash-output-tcp.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-output-tcp'
-  s.version         = '6.0.2'
+  s.version         = '6.1.0'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Writes events over a TCP socket"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"
@@ -21,11 +21,14 @@ Gem::Specification.new do |s|
 
   # Gem dependencies
   s.add_runtime_dependency "logstash-core-plugin-api", ">= 1.60", "<= 2.99"
-
+  s.add_runtime_dependency 'logstash-core', '>= 8.1.0'
   s.add_runtime_dependency 'logstash-codec-json'
   s.add_runtime_dependency 'stud'
 
+  s.add_runtime_dependency 'jruby-openssl', '>= 0.12.2' # 0.12 supports TLSv1.3
+
   s.add_development_dependency 'logstash-devutils'
+  s.add_development_dependency 'logstash-codec-plain'
   s.add_development_dependency 'flores'
 end