Class: SSRFProxy::Server

Inherits:
Object
  • Object
show all
Includes:
Celluloid::IO
Defined in:
lib/ssrf_proxy/server.rb

Overview

SSRFProxy::Server takes a SSRFProxy::HTTP object, interface and port, and starts a HTTP proxy server on the specified interface and port. All client HTTP requests are sent via the specified SSRFProxy::HTTP object.

Defined Under Namespace

Modules: Error

Instance Method Summary collapse

Constructor Details

#initialize(ssrf, interface = '127.0.0.1', port = 8081) ⇒ Server

Start the local server and listen for connections

Examples:

Start SSRF Proxy server with the default options

ssrf_proxy = SSRFProxy::Server.new(
  SSRFProxy::HTTP.new('http://example.local/index.php?url=xxURLxx'),
  '127.0.0.1',
  8081)
ssrf_proxy.serve

Parameters:

  • ssrf (SSRFProxy::HTTP) —

    A configured SSRFProxy::HTTP object

  • interface (String) (defaults to: '127.0.0.1') —

    Listen interface (Default: 127.0.0.1)

  • port (Integer) (defaults to: 8081) —

    Listen port (Default: 8081)

Raises:

  • (SSRFProxy::Server::Error::InvalidSsrf) —

    Invalid SSRFProxy::SSRF object provided.

  • (SSRFProxy::Server::Error::ProxyRecursion) —

    Proxy recursion error. SSRF Proxy cannot use itself as an upstream proxy.

  • (SSRFProxy::Server::Error::RemoteProxyUnresponsive) —

    Could not connect to remote proxy.

  • (SSRFProxy::Server::Error::AddressInUse) —

    Could not bind to the port on the specified interface as address already in use.



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# File 'lib/ssrf_proxy/server.rb', line 59

def initialize(ssrf, interface = '127.0.0.1', port = 8081)
  @banner = 'SSRF Proxy'
  @server = nil
  @max_request_len = 8192
  @logger = ::Logger.new(STDOUT).tap do |log|
    log.progname = 'ssrf-proxy-server'
    log.level = ::Logger::WARN
    log.datetime_format = '%Y-%m-%d %H:%M:%S '
  end
  # set ssrf
  unless ssrf.class == SSRFProxy::HTTP
    raise SSRFProxy::Server::Error::InvalidSsrf.new,
          'Invalid SSRF provided'
  end
  @ssrf = ssrf

  # check if the remote proxy server is responsive
  unless @ssrf.proxy.nil?
    if @ssrf.proxy.host == interface && @ssrf.proxy.port == port
      raise SSRFProxy::Server::Error::ProxyRecursion.new,
            "Proxy recursion error: #{@ssrf.proxy}"
    end
    if port_open?(@ssrf.proxy.host, @ssrf.proxy.port)
      print_good("Connected to remote proxy #{@ssrf.proxy.host}:#{@ssrf.proxy.port} successfully")
    else
      raise SSRFProxy::Server::Error::RemoteProxyUnresponsive.new,
            "Could not connect to remote proxy #{@ssrf.proxy.host}:#{@ssrf.proxy.port}"
    end
  end

  # if no upstream proxy is set, check if the remote server is responsive
  if @ssrf.proxy.nil?
    if port_open?(@ssrf.host, @ssrf.port)
      print_good("Connected to remote host #{@ssrf.host}:#{@ssrf.port} successfully")
    else
      raise SSRFProxy::Server::Error::RemoteHostUnresponsive.new,
            "Could not connect to remote host #{@ssrf.host}:#{@ssrf.port}"
    end
  end

  # start server
  logger.info "Starting HTTP proxy on #{interface}:#{port}"
  begin
    print_status "Listening on #{interface}:#{port}"
    @server = TCPServer.new(interface, port.to_i)
  rescue Errno::EADDRINUSE
    raise SSRFProxy::Server::Error::AddressInUse.new,
          "Could not bind to #{interface}:#{port} - address already in use"
  end
end

Instance Method Details

#logger ⇒ Logger

Logger accessor

Returns:

  • (Logger) —

    class logger object



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# File 'lib/ssrf_proxy/server.rb', line 163

def logger
  @logger
end

#serve ⇒ Object

Run proxy server asynchronously



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# File 'lib/ssrf_proxy/server.rb', line 170

def serve
  loop { async.handle_connection(@server.accept) }
end