Fix missing SSL hostname validation [MiM Vuln]
user
```ruby
require 'openssl'

module EventMachine
  # Provides the ssl_verify_peer method to EM::IMAP::Connection to verify certificates
  # for use in ssl connections
  #
  module IMAP
    module Connection
      def ssl_verify_peer(cert_string)
        cert = nil
        begin
          cert = OpenSSL::X509::Certificate.new(cert_string)
        rescue OpenSSL::X509::CertificateError
          return false
        end

        @last_seen_cert = cert

        if certificate_store.verify(@last_seen_cert)
          begin
            certificate_store.add_cert(@last_seen_cert)
          rescue OpenSSL::X509::StoreError => e
            raise e unless e.message == 'cert already in hash table'
          end
          true
        else
          raise OpenSSL::SSL::SSLError.new(%(unable to verify the server certificate for "#{host}"))
        end
      end

      def ssl_handshake_completed
        return true unless verify_peer?
        unless OpenSSL::SSL.verify_certificate_identity(@last_seen_cert, host)
          raise OpenSSL::SSL::SSLError.new(%(host "#{host}" does not match the server certificate))
        else
          true
        end
      end


      def verify_peer?
        true
#        parent.connopts.tls[:verify_peer]
      end

      def certificate_store
        @certificate_store ||= begin
          store = OpenSSL::X509::Store.new
          store.set_default_paths
#          ca_file = parent.connopts.tls[:cert_chain_file]
          ca_file = nil
          store.add_file(ca_file) if ca_file
          store
        end


      end
    end
  end
end

```
assistant