Re: openssh: privilege separation no longer supported on Cygwin? SURPRISE!

[cyg Simple <cygsimple@gmail.com>]

On 5/31/2017 5:37 AM, Houder wrote:
> On Tue, 30 May 2017 21:28:41, "Larry Hall (Cygwin)" wrote:
> 
> [snip]
>> Cygwin's link to the Windows user ID is through the UID/SID mapping.  In
>> your case, you're apparently using /etc/passwd and so that's where the
>> mapping happens.  You can map the UID of a Cygwin user to any valid Windows
>> SID by editing the SID as you did.  This doesn't change how things look in
>> the Cygwin environment (i.e. the UID and user name are still the same) but
>> it does make a difference to Windows.  So the fact that you can change the
>> SID for the 'sshd' user and still get it to run is not all that surprising,
>> assuming that the new Windows SID that you're using as 'sshd' now has at
>> least similar permissions.  Of course, if you remove Cygwin's understanding
>> of 'sshd' so that it can't do the mapping of UID to SID or even have a
>> valid UID, then subsequent problems are not unexpected.
> 
> Hi Larry,
> 
> Thanks for your reply! Discussion!
> 
> First of all, I do not pretend to know Windows ... neither do I pretend that I
> know more about ssh/Cygwin than Corinna does (basically, I know not very much).
> 
> .. the only thing I am able to, is "observe" (and I may interpret wrong), and
> may have done "stupid" things. That is why your reply is appreciated by me.
> 
> Now back to your reply:
> 
> I had modified /etc/password as follows: (note the xxxx in the sid)
> 
> sshd:*:1015:513:U-Seven\sshd,S-1-5-21-91509220-1575020443-2714799223-xxxx:/var/empty:/bin/false
> 
> However, just now I modified it as follows:
> 
> sshd:*:1015:513:U-Seven\sshd,S-1-5-21-xxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-xxxx:/var/empty:/bin/false
> 
> (again changed the sshd service into 'automatic'), and rebooted the system.
> 
> After system reboot, an elevated shell is started ...
> (the ampersand sign at the end of the prompt indicates it is an elevated shell)

All of this talk of /etc/passwd leads me to point you to
https://cygwin.com/cygwin-ug-net/ntsec.html.

-- 
cyg Simple

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