Re: chmod g+s ineffective

[Chris Wagner <wagnerc@plebeian.com>]

>> On 6/29/2022 9:18 AM, Norton Allen wrote:
>>>>> On one machine I have, chmod g+s fails to set the sticky bit. The 
>>>>> >>> command
>>>>> does not return any error, but ls -l continues to show the bit not 
>>>>> set.
>>>>>      $ mkdir foo
>>>>>      $ chgrp flight foo
>>>>>      $ chmod g+ws foo
>>>>>      $ ls -ld foo
>>>>>      drwxrwxr-x+ 1 nort flight 0 Jun 29 06:50 foo

Hi.  The permission bits are implemented as normal Window's DACLs 
(Discretionary Access List).  +s is implemented magically with the NULL 
SID.  You can view it from Explorer or with icacls.  Try checking the 
return code (echo $?) from chmod.  Also try changing perms from 
Explorer.  You might not be able to set the NULL SID for some reason.

It works for me:
$ ls -ld z
drwxrwsr-x+ 1 wagnerc Users 0 Nov 24  2020 z

$ getfacl z
# file: z
# owner: wagnerc
# group: Users
# flags: -s-
user::rwx
group::r-x
group:Administrators:rwx
group:Users:rwx
mask::rwx
other::r-x
default:user::rwx
default:user:wagnerc:rwx
default:group::r-x
default:group:Administrators:rwx
default:group:Users:rwx
default:mask::rwx
default:other::r-x


$ icacls z
z NULL SID:(DENY)(Rc,S,WD,REA,WEA,X,DC)
   APPLEJACK\wagnerc:(F)
   BUILTIN\Users:(RX)
   BUILTIN\Administrators:(RX,W,DC)
   BUILTIN\Users:(RX,W,DC)
   Everyone:(RX)
   NULL SID:(OI)(CI)(IO)(DENY)(Rc,S,WD,REA,WEA,X,DC)
   CREATOR OWNER:(OI)(CI)(IO)(F)
   APPLEJACK\wagnerc:(OI)(CI)(IO)(RX,W,DC)
   BUILTIN\Users:(OI)(CI)(IO)(RX)
   BUILTIN\Administrators:(OI)(CI)(IO)(RX,W,DC)
   BUILTIN\Users:(OI)(CI)(IO)(RX,W,DC)
   Everyone:(OI)(CI)(IO)(RX)

Successfully processed 1 files; Failed processing 0 files

$ uname -a
CYGWIN_NT-6.1 applejack 3.1.0(0.340/5/3) 2019-11-19 13:58 x86_64 Cygwin



Thanks.