Exception in tunnel manager with key-based SSH tunnels

[Liam Gretton]

Workbench 6.2.3.12312 build 2280 (64-bit) on Win7.

Since upgrading to 6.2.3, connections to hosts through SSH tunnels no longer works with key-based auth to any host. I'm using Pageant as a key manager.

On attempting to connect, WB reports:

Authentication error, unhandled exception caught in tunnel manager, please refer to logs for details

Here's the relevent section from the log:

08:11:36 [INF][ SSH tunnel]: Starting tunnel
08:11:36 [DB2][ python context]: About to pyrun 'C:\Program Files\MySQL\MySQL Workbench 6.2 CE\sshtunnel.py'
08:11:36 [INF][ SSH tunnel]: Existing SSH tunnel not found, opening new one
08:11:36 [INF][ SSH tunnel]: Opening SSH tunnel to host.redacted.uk
08:11:36 [DB1][ grt]: Thread started
08:11:36 [DB2][sshtunnel.py:do_run:117]: SSH Tunel 1 thread started
08:11:36 [DB2][sshtunnel.py:notify:228]: tunnel_55233: INFO Connecting to SSH server at host.redacted.uk:22 using key C:\Users\lgretton\Documents\SSH Keys\[e-mail]...
08:11:36 [DB1][ SSH tunnel]: Waiting on tunnel to connect...
08:11:36 [DB1][sshtunnel.py:wait_connection:446]: INFO: Connecting to SSH server at host.redacted.uk:22 using key C:\Users\lgretton\Documents\SSH Keys\[e-mail]...
08:11:36 [DB2][sshtunnel.py:notify:228]: tunnel_55233: ERROR Authentication error, unhandled exception caught in tunnel manager, please refer to logs for details
08:11:36 [ERR][sshtunnel.py:notify_exception_error:233]: Traceback (most recent call last):
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE\sshtunnel.py", line 265, in _connect_ssh
look_for_keys=has_key, allow_agent=has_key)
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE/python/site-packages\paramiko\client.py", line 332, in connect
self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys)
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE/python/site-packages\paramiko\client.py", line 445, in _auth
self._agent = Agent()
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE/python/site-packages\paramiko\agent.py", line 78, in __init__
ptype, result = self._send_message(chr(SSH2_AGENTC_REQUEST_IDENTITIES))
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE/python/site-packages\paramiko\agent.py", line 110, in _send_message
l = self._read_all(4)
File "C:\Program Files\MySQL\MySQL Workbench 6.2 CE/python/site-packages\paramiko\agent.py", line 118, in _read_all
raise SSHException('lost ssh-agent')
SSHException: lost ssh-agent

08:11:36 [DB1][sshtunnel.py:do_run:225]: Leaving tunnel thread 55233

Pageant works happily for other applications, and my previous version of WB (6.1.7.11891) was also fine.

This looks similar to a previous WB bug: #65672.