diff --git a/dulwich/contrib/paramiko_vendor.py b/dulwich/contrib/paramiko_vendor.py
index 00d7f215..9cb748fe 100644
--- a/dulwich/contrib/paramiko_vendor.py
+++ b/dulwich/contrib/paramiko_vendor.py
@@ -1,152 +1,152 @@
 # paramiko_vendor.py -- paramiko implementation of the SSHVendor interface
 # Copyright (C) 2013 Aaron O'Mullan <aaron.omullan@friendco.de>
 #
 # Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
 # General Public License as public by the Free Software Foundation; version 2.0
 # or (at your option) any later version. You can redistribute it and/or
 # modify it under the terms of either of these two licenses.
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
 # You should have received a copy of the licenses; if not, see
 # <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
 # and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
 # License, Version 2.0.
 #
 
 """Paramiko SSH support for Dulwich.
 
 To use this implementation as the SSH implementation in Dulwich, override
 the dulwich.client.get_ssh_vendor attribute:
 
   >>> from dulwich import client as _mod_client
   >>> from dulwich.contrib.paramiko_vendor import ParamikoSSHVendor
   >>> _mod_client.get_ssh_vendor = ParamikoSSHVendor
 
 This implementation is experimental and does not have any tests.
 """
 
 import paramiko
 import paramiko.client
 import threading
 
 
 class _ParamikoWrapper(object):
     STDERR_READ_N = 2048  # 2k
 
     def __init__(self, client, channel, progress_stderr=None):
         self.client = client
         self.channel = channel
         self.progress_stderr = progress_stderr
         self.should_monitor = bool(progress_stderr) or True
         self.monitor_thread = None
         self.stderr = b''
 
         # Channel must block
         self.channel.setblocking(True)
 
         # Start
         if self.should_monitor:
             self.monitor_thread = threading.Thread(
                 target=self.monitor_stderr)
             self.monitor_thread.start()
 
     def monitor_stderr(self):
         while self.should_monitor:
             # Block and read
             data = self.read_stderr(self.STDERR_READ_N)
 
             # Socket closed
             if not data:
                 self.should_monitor = False
                 break
 
             # Emit data
             if self.progress_stderr:
                 self.progress_stderr(data)
 
             # Append to buffer
             self.stderr += data
 
     def stop_monitoring(self):
         # Stop StdErr thread
         if self.should_monitor:
             self.should_monitor = False
             self.monitor_thread.join()
 
             # Get left over data
             data = self.channel.in_stderr_buffer.empty()
             self.stderr += data
 
     def can_read(self):
         return self.channel.recv_ready()
 
     def write(self, data):
         return self.channel.sendall(data)
 
     def read_stderr(self, n):
         return self.channel.recv_stderr(n)
 
     def read(self, n=None):
         data = self.channel.recv(n)
         data_len = len(data)
 
         # Closed socket
         if not data:
-            return
+            return b''
 
         # Read more if needed
         if n and data_len < n:
             diff_len = n - data_len
             return data + self.read(diff_len)
         return data
 
     def close(self):
         self.channel.close()
         self.stop_monitoring()
 
 
 class ParamikoSSHVendor(object):
     # http://docs.paramiko.org/en/2.4/api/client.html
 
     def __init__(self, **kwargs):
         self.kwargs = kwargs
 
     def run_command(self, host, command,
                     username=None, port=None,
                     progress_stderr=None,
                     password=None, pkey=None,
                     key_filename=None, **kwargs):
 
         client = paramiko.SSHClient()
 
         connection_kwargs = {'hostname': host}
         connection_kwargs.update(self.kwargs)
         if username:
             connection_kwargs['username'] = username
         if port:
             connection_kwargs['port'] = port
         if password:
             connection_kwargs['password'] = password
         if pkey:
             connection_kwargs['pkey'] = pkey
         if key_filename:
             connection_kwargs['key_filename'] = key_filename
         connection_kwargs.update(kwargs)
 
         policy = paramiko.client.MissingHostKeyPolicy()
         client.set_missing_host_key_policy(policy)
         client.connect(**connection_kwargs)
 
         # Open SSH session
         channel = client.get_transport().open_session()
 
         # Run commands
         channel.exec_command(command)
 
         return _ParamikoWrapper(
             client, channel, progress_stderr=progress_stderr)