From: Andrey Repin <anrdaemon@yandex.ru>
To: Orgad Shaneh <orgads@gmail.com>, cygwin@cygwin.com
Subject: Re: A problem with noacl+umask+chmod result
Date: Fri, 9 Apr 2021 04:45:12 +0300 [thread overview]
Message-ID: <1462778363.20210409044512@yandex.ru> (raw)
In-Reply-To: <CAGHpTB+wcf_tcXo_W20CAq-3n=xBq5Ry6Tpt7WmZREvAbOkPSg@mail.gmail.com>
Greetings, Orgad Shaneh!
> On Wed, Apr 7, 2021 at 11:47 PM Orgad Shaneh <orgads@gmail.com> wrote:
>>
>> Hi,
>>
>> If a filesystem is mounted with noacl, calling chmod to add write
>> permissions after umasking this permission doesn't work. Demonstrated
>> with command-line and C++.
>>
>> Did I miss something or is this a real bug? According to umask man, it
>> should only affect newly created files and directories, but I didn't
>> find anything that relates to chmod.
>>
>> Command-line:
>> touch foo
>> ls -l foo
>> # -rw-r--r-- ... foo
>> umask 200
>> chmod 0 foo
>> ls -l foo
>> # -r--r--r-- ... foo
>> chmod 200 foo
>> ls -l foo
>> # -r--r--r-- ... foo
>> # Expected to have rw
> Marco Atzeri replied to the mailing list but did not CC me, so I
> didn't receive it:
The expectation is that you subscribe to the list of interest.
>> without ACL you can not expect the POSIX scheme to properly work.
>> see
>> https://cygwin.com/cygwin-ug-net/ntsec.html
>> to understand how Cygwin uses ACL to mimic POSIX permissions
> Thanks Marco!
> I'm well aware of that. I don't expect it to work properly. From what
> I know, it can only set/unset user write bit. Read bits are always
> enabled, even on chmod 0.
> What I do expect is that the write bit will not be affected by umask.
> umask should only affect newly created files, not direct chmod
> commands.
Yet again: using chmod on noacl filesystem is likely to cause more harm than
good. You may very well end up with an unusable filesystem until you fix
permissions by hands.
--
With best regards,
Andrey Repin
Friday, April 9, 2021 4:43:01
Sorry for my terrible english...
next prev parent reply other threads:[~2021-04-09 1:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 20:47 Orgad Shaneh
2021-04-08 5:48 ` Marco Atzeri
2021-04-08 20:28 ` Orgad Shaneh
2021-04-09 1:45 ` Andrey Repin [this message]
2021-04-09 4:34 ` Orgad Shaneh
2021-04-17 17:11 ` Kaz Kylheku (Cygwin)
2021-04-17 20:29 ` Brian Inglis
2021-04-18 7:13 ` Orgad Shaneh
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