sshd service removed by Windows 10 update 1803
As part of a Windows 10 update 1803 a few days ago, the cygwin sshd service was
removed, keeping my users from accessing my server. I had been successfully
using sshd for several years and it has survived numerous windows updates.
Here is what I have done to fix it:
Disable the following services via W10 computer management.
OpenSSH Authentication Agent
SSH Server Broker
SSH Server Proxy
I'm not sure all those need to be disabled.
Run a bash shell as administrator, and reinstall sshd using cygrunsrv
cygrunsrv --stop sshd
cygrunsrv --remove sshd
cygrunsrv --install sshd --path /usr/sbin/sshd.exe --user cyg_server
cygrunsrv --start sshd
You will get an error from the start command:
cygrunsrv: Error starting a service: QueryServiceStatus: Win32 error 1062:
The service has not been started.
The task manager shows sshd is indeed running, and remote ssh clients can log
in. So I am ignoring the error.
cygrunsrv -Q sshd shows the service is stopped. And W10 computer management
shows it is stopped. If you try to start it again, it will fail because the
sshd task has a hold on the TCP ports. If you want to stop/restart to edit
config files, you need to directly kill the sshd task.
After a system restart, W10 starts the correct sshd again.
Simply using "cygrunsrv --install sshd" without --path, installs the MS sshd.
Not what I want.
If you don't specify --user with the --install, W10 will use SYSTEM which does
not have the permissions (SeTcbPrivilege etc) to change to the client user. So
you get seteuid Operation Not Permitted errors when a remote client tries and
fails to login. I discovered this the hard way.
BTW, I didn't want to start over with ssh-host-config because I didn't want to
risk invalidating my encryption keys and confuse my remote clients.
Except for the weirdness where computer management and cygrunsrv -Q show the
service is stopped, everything seems to work okay and my users are happy again.
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