Re: Cygwin's ACL handling is NOT interoperable with Windows

[Andrey Repin]

Greetings, R0b0t1!

>> Please feel free to provide, using your superior understanding, a detailed 
>> spec
>> for how POSIX ACLs and permissions should be implemented using Windows ACLs
>> while maintaining "canonical" ACL order.

> Or at the very least can another explanation of what is wrong be
> offered? I still don't get it.

As has been said, certain POSIX-specific behavior can't be translated to
canonical ACE order.
Though I'm using noacl mounts, so I yet to face such issue myself.

P.S.
Please tech your mail agent to not quote raw email addresses.
Don't feed spambots.


-- 
With best regards,
Andrey Repin
Tuesday, August 7, 2018 0:08:01

Sorry for my terrible english...


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Re: Cygwin's ACL handling is NOT interoperable with Windows

[R0b0t1]

On Mon, Aug 6, 2018 at 10:49 AM, Brian Inglis
 wrote:
>
> Please feel free to provide, using your superior understanding, a detailed 
> spec
> for how POSIX ACLs and permissions should be implemented using Windows ACLs
> while maintaining "canonical" ACL order.

Or at the very least can another explanation of what is wrong be
offered? I still don't get it.

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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Brian Inglis]

On 2018-08-05 08:23, Stefan Kanthak wrote:
> Andrey Repin wrote:
>> Greetings, Stefan Kanthak!
>>> PS: 
>>> too states bloody lies:
>>> | The Windows subsystem only supports CWD paths of up to 258 chars.
>> 260 including drive letter.
> WRONG, AGAIN!
> 260 is the value of MAX_PATH, which accounts for the trailing \0, and
> commonly used as
> | char buffer[MAX_PATH];
> I recommend to read
> 
> VERY careful!
>>> The Win32 API supports pathnames with up to 32767 (Unicode) characters; 
>>> this includes of course the CWD!
>> CWD may be, but command processor does not.
> Neither Cygwin's WRONG documentation nor I referred to the command processor.

Please feel free to provide, using your superior understanding, a detailed spec
for how POSIX ACLs and permissions should be implemented using Windows ACLs
while maintaining "canonical" ACL order.
Windows "canonical" order is preferred because it allows Windows to make short
cut assumptions to meet Windows' security policy objectives.
But MS do not enforce that order in the kernel ACL mechanism because they
recognize that other customers may have different security policy objectives
which may be better achieved using different ACLs and orders.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Michael Wild]

On Sun, Aug 5, 2018 at 5:35 PM Andrey Repin  wrote:

> Greetings, Stefan Kanthak!
>
> > Andrey Repin wrote:
>
> >> Greetings, Stefan Kanthak!
> >>
> >>> PS: 
> >>> too states bloody lies:
> >>
> >>> | The Windows subsystem only supports CWD paths of up to 258 chars.
> >  ~~~
> >>
> >> 260 including drive letter.
>
> > WRONG, AGAIN!
> > 260 is the value of MAX_PATH, which accounts for the trailing \0, and
> > commonly used as
>
> > | char buffer[MAX_PATH];
>
> > I recommend to read
> > 
> > VERY careful!
>
> >>> The Win32 API supports pathnames with up to 32767 (Unicode)
> characters;
> >>> this includes of course the CWD!
> >>
> >> CWD may be, but command processor does not.
>
> > Neither Cygwin's WRONG documentation nor I referred to the command
> processor.
>
> I think, this is an appropriate response to the underlying issue:
> https://xkcd.com/386


+1 from me.

I propose to ignore Stefan until he learns his manners, is less
cantankerous and maybe even volunteers to submit a patch if indeed there is
a problem with the ACL handling (although, to be honest, I can hardly
imagine it, Corinna being involved...).

Michael

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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Andrey Repin]

Greetings, Stefan Kanthak!

> Andrey Repin wrote:

>> Greetings, Stefan Kanthak!
>> 
>>> PS: 
>>> too states bloody lies:
>> 
>>> | The Windows subsystem only supports CWD paths of up to 258 chars.
>  ~~~
>> 
>> 260 including drive letter.

> WRONG, AGAIN!
> 260 is the value of MAX_PATH, which accounts for the trailing \0, and
> commonly used as

> | char buffer[MAX_PATH];

> I recommend to read
> 
> VERY careful!

>>> The Win32 API supports pathnames with up to 32767 (Unicode) characters;
>>> this includes of course the CWD!
>> 
>> CWD may be, but command processor does not.

> Neither Cygwin's WRONG documentation nor I referred to the command processor.

I think, this is an appropriate response to the underlying issue:
https://xkcd.com/386/


-- 
With best regards,
Andrey Repin
Sunday, August 5, 2018 18:21:42

Sorry for my terrible english...


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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Stefan Kanthak]

Andrey Repin wrote:

> Greetings, Stefan Kanthak!
> 
>> PS: 
>> too states bloody lies:
> 
>> | The Windows subsystem only supports CWD paths of up to 258 chars.
 ~~~
> 
> 260 including drive letter.

WRONG, AGAIN!
260 is the value of MAX_PATH, which accounts for the trailing \0, and
commonly used as

| char buffer[MAX_PATH];

I recommend to read

VERY careful!

>> The Win32 API supports pathnames with up to 32767 (Unicode) characters;
>> this includes of course the CWD!
> 
> CWD may be, but command processor does not.

Neither Cygwin's WRONG documentation nor I referred to the command processor.

regards
Stefan

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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Andrey Repin]

Greetings, Stefan Kanthak!

> PS: 
> too states bloody lies:

> | The Windows subsystem only supports CWD paths of up to 258 chars.

260 including drive letter.

> The Win32 API supports pathnames with up to 32767 (Unicode) characters;
> this includes of course the CWD!

CWD may be, but command processor does not.
I had a wonderful sex just a few hours ago trying to handle *.eml in a
directory and missing on 3 files over and over again, until I've listed
them with dir and see them cut in the middle.


-- 
With best regards,
Andrey Repin
Sunday, August 5, 2018 17:02:07

Sorry for my terrible english...


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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Michael Wild]

Hi Stefan

On Sat, 4 Aug 2018, 19:12 Stefan Kanthak,  wrote:

> [...]
> As Cygwin is a guest in the house of Windows, it should respect its hosts
> house rules; instead it but violates them, and blames the host for its
> faults!

 [...]
>
> Fix Cygwin's BUGGY ACL creation!
>
> [...]
>
> PS: 
> too states bloody lies:


Wow, man, you really know how to make people *not* want to help you. Cygwin
is a volunteer effort. Nobody ows you the tiniest bit. You paid for
nothing, you got something for free and now you curse about it?! Show some
humility and respect, tone it down a bit. Works wonders.

Michael

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Re: Cygwin's ACL handling is NOT interoperable with Windows

[Marco Atzeri]

Am 04.08.2018 um 19:11 schrieb Stefan Kanthak:

Hi,


Hi Stefan,



 states:

| There's just one problem when trying to map the POSIX permission model
| onto the Windows permission model.
...
| Canonical ACLs are unable to reflect each possible combination of POSIX
| permissions.
...
| Again: This works on all supported versions of Windows. Only the GUIs
| aren't able (or willing) to deal with that order.

These last two statements are wrong:

* the first statement holds ONLY because of the LIMITATION of the POSIX
   permissions; it is WRONG for the general case, which ALL Windows
   interfaces/components need to consider and handle, EVERYWHERE!


Cygwin aims to POSIX compliance, using the tool given by Windows.
Have you tested all the possible POSIX permissions and verified that
it is possible to replicate with windows ACL ?
Please note that ACL were not created by Microsoft.


* the second statement is a blatant lie: to guarantee CORRECT
   interpretation of arbitrary ACLs, ALL Windows interfaces/components,
   not just the "GUIs", MUST create CANONICAL ACLs only.


That is your opinion.
About the "lie", may I suggest you an old Italian classic

"Galateo of Manners & Behaviours by Giovanni Della Casa"
http://www.gutenberg.org/ebooks/47993



   This especially means that not just Windows Explorer, but also the
   command processor with its builtin COPY command as well as the
   CopyFile() 
   API (just to pick 3 examples) bring INHERITED ACEs into their PROPER
   canonical order.

As Cygwin is a guest in the house of Windows, it should respect its hosts
house rules; instead it but violates them, and blames the host for its
faults!


What is your problem ?

If you don't like how cygwin is behaving, you can:

- stop to use it
- propose a change (with a patch of course)
- learn to use it without venting


Fix Cygwin's BUGGY ACL creation!


Cool down. You paid nothing, we own you nothing.

No one here is paid to solve your "theorical" problem;
if you know a better way to handle the POSIX permissions
show us the code and we can discuss.


regards
Stefan Kanthak


Best Regards
Marco

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