Problem with "None" Group on Non-Domain Members

[Chris J. Breisch]

Chris J. Breisch wrote:
> Larry Hall (Cygwin) wrote:
>> On 05/05/2014 02:56 PM, Chris J. Breisch wrote:
>>> 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. :)
>>>
>>
>> I'm wondering if we're getting the user id as the group for the MS
>> Account because there is no group id. Chris, what does 'id' for
>> each of these accounts look like and is the group id (assuming they
>> are different that the user id) in there?
>>
>>
>
> Well, I hope I'm not comparing apples and oranges, because now I'm at
> home. However, I have duplicated the scenario and results on this
> machine. It was actually where I noticed it first.
>
> id produces expected results:
>
> MS account:
> $ id
> uid=1001(Chris) gid=513(None) groups=513(None),545(Users),1003(HomeUsers)
>
> Local account:
> $ id
> uid=1007(cjb) gid=513(None) groups=513(None),545(Users),1003(HomeUsers)
>
> Actually, it's not quite what I expected. Chris is in the Administrators
> group, and that's not shown.
>
> $ net user Chris
> User name Chris
> Full Name Chris Breisch
> Comment
> User's comment
> Country/region code 001 (United States)
> Account active Yes
> Account expires Never
>
> [snip PW stuff for Cygwin filter]
>
> Workstations allowed All
> Logon script
> User profile
> Home directory
> Last logon 5/1/2014 8:39:44 PM
>
> Logon hours allowed All
>
> Local Group Memberships *Administrators *HomeUsers
> *Users
> Global Group memberships *None
> The command completed successfully.
>
> $ net user cjb
> User name cjb
> Full Name cjb
> Comment
> User's comment
> Country/region code 000 (System Default)
> Account active Yes
> Account expires Never
>
> [snip]
>
> Workstations allowed All
> Logon script
> User profile
> Home directory
> Last logon 5/5/2014 5:40:39 PM
>
> Logon hours allowed All
>
> Local Group Memberships *HomeUsers *Users
> Global Group memberships *None
> The command completed successfully.
>
>
Hmmm, just noticed something in /etc/group:

Chris J. Breisch:S-1-5-21-3514886939-1786686319-3519756147-1001:11001:

and on another machine where I can reproduce this:
Chris:S-1-5-21-1055441198-2882714470-4103286779-1001:11001:

Oddly, mkgroup -l does not produce this line on either machine, so I'm 
not sure where it came from. In both cases, the SID for the group is the 
same as the my user's SID.


-- 
Chris J. Breisch

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