Re: Problem with "None" Group on Non-Domain Members

["Chris J. Breisch" <chris.ml@breisch.org>]

Corinna Vinschen wrote:
> On May  5 12:17, Chris J. Breisch wrote:
>> Corinna Vinschen wrote:
>>> An strace of `chmod 400 bar' might sched some light on this issue, but I
>>> have a gut feeling the underlying WIndows call will not even return an
>>> error code...
>> Attached. Your gut seems to be working today...
>
> There *is* something weird here.  Look at this:
>
>>    151   36702 [main] chmod 5536 alloc_sd: uid 1001, gid 513, attribute 0x2190
>>     65   36767 [main] chmod 5536 cygsid::debug_print: alloc_sd: owner SID = S-1-5-21-3514886939-1786686319-3519756147-1001 (+)
>>     70   36837 [main] chmod 5536 cygsid::debug_print: alloc_sd: group SID = S-1-5-21-3514886939-1786686319-3519756147-1001 (+)
>
> alloc_sd (the underlying function creating a security descriptor) gets
> a uid 1001 and gid 513 as input, as usual.  But the owner *and* group
> SIDs of the file's existing security descriptor is
> S-1-5-21-3514886939-1786686319-3519756147-1001, the SID of your user
> account.
>
> Why is your user account the primary group of the file, even though
> your user token definitely has "None" (513) as its primary group?
> How did it get there?
>
I don't have a clue. You're the expert. :)

The ACLs are a little different between the Microsoft Account and the 
regular local account. But, if anything, it's the regular one that looks 
odd to me.

Microsoft Account:
$ icacls bar
bar WIN8-VM\Chris:(R,D,WDAC,WO,WA)
     Everyone:(Rc,S,RA)
     NT AUTHORITY\Authenticated Users:(M)


Local account:
$ icacls foo
foo WIN8-VM\cjb:(R,D,WDAC,WO,WA)
     WIN8-VM\None:(Rc,S,RA)
     Everyone:(Rc,S,RA)

Why does the local account have None permissions, and not Authenticated 
Users?

> Is that something enforced by the "Microsoft accounts", perhaps?
>
> I just had a look into the Local Security Policy settings, and I can't
> see any related setting.
>
I have no clue. If you want to throw some more debugging code into a 
snapshot, I'll happily test it. I'll do whatever you want, even shut up 
and go away. :)

I should point out that all of this is with Cygwin64. From what we've 
discovered so far, it seems likely that I'll get the same behavior under 
Cygwin32. But I'll verify that tonight when I get home.


-- 
Chris J. Breisch

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