From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: Microsoft Accounts (was Re: Problem with "None" Group on Non-Domain Members)
Date: Wed, 07 May 2014 14:35:00 -0000 [thread overview]
Message-ID: <20140507143457.GK30918@calimero.vinschen.de> (raw)
In-Reply-To: <536A3DA3.8060508@breisch.org>
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On May 7 10:05, Chris J. Breisch wrote:
> Corinna Vinschen wrote:
> >I toyed around with the Microsoft Account a bit more. And here's why
> >the primary group SID being identical to the user SID is not a good
> >idea:
> >
> > Security checks.
> >
> >For instance:
> >
> > $ echo $USER
> > VMBERT8164+local_000
> > $ screen
> > Directory /tmp/uscreens/S-VMBERT8164+local_000 must have mode 700.
> >
> >Huh?
> >
> > $ ls -l /tmp/uscreens/
> > total 0
> > drwxrwx---+ 1 VMBERT8164+local_000 VMBERT8164+local_000 0 May 7 12:44 S-VMBERT8164+local_000
> >
> >Uh Oh.
> >
> >This will be a problem with other security sensitive applications, too.
> >Sshd comes to mind.
> >
> Yes, it was when dealing with ssh that I discovered this issue, and
> was the reason I brought it up. Ssh wants many of its files to be
> only accessible by the owner, and not any group.
>
> >So I guess we really should make sure the primary group SID is some
> >valid group, not the user's SID.
> >
> >"None" is not an option since it's not in the user token group list.
> >
> >"Users" seems to be the best choice at first sight.
> >
> That's what I've thought from the beginning.
>
> >Alternatively we could use the S-1-11-xxx SID of the Microsoft Account.
> >That would be in line with the idea to have a user-specific primary
> >group.
> >
> I'm not sure how that helps or even would work. Are you talking
> about creating a group just for Cygwin purposes that wouldn't map to
> an actual group on the box?
No. As I explained in my mail from yesterday
http://cygwin.com/ml/cygwin/2014-05/msg00083.html
as soon as you login with your Microsoft account, your user token
contains a special SID which connects your local account with the
Microsoft Account. It's the account from Windows' whoami /groups
which is called "MicrosoftAccount\<your email>" and a SID starting
with S-1-11-*. Using the latest Cygwin developer snapshots, you'll
see something along thse lines in `id' output:
$ id
uid=197613(VMBERT8164+local_000) gid=197613(VMBERT8164+local_000) groups=197613(VMBERT8164+local_000),401408(+Medium Mandatory Level),555(+Remote Desktop Users),545(+Users),14(+REMOTE INTERACTIVE LOGON),4(+INTERACTIVE),11(+Authenticated Users),15(+This Organization),68452(MicrosoftAccount+testuser@foobar.de),113(+Local account),4095(CurrentSession),66048(+LOCAL),262176(+Microsoft Account Authentication)
If we use this account as primary group, you would have both, a
unambiguous group gid and a user-specific group.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
Red Hat
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next prev parent reply other threads:[~2014-05-07 14:35 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 13:49 Problem with "None" Group on Non-Domain Members Chris J. Breisch
2014-05-05 13:59 ` Corinna Vinschen
2014-05-05 14:17 ` Chris J. Breisch
2014-05-05 14:47 ` Corinna Vinschen
2014-05-05 15:23 ` Chris J. Breisch
2014-05-05 15:42 ` Corinna Vinschen
2014-05-05 16:17 ` Chris J. Breisch
2014-05-05 16:57 ` Corinna Vinschen
2014-05-05 18:52 ` Robert Pendell
2014-05-06 13:02 ` Corinna Vinschen
2014-05-05 18:56 ` Chris J. Breisch
2014-05-05 19:44 ` Larry Hall (Cygwin)
2014-05-05 21:57 ` Chris J. Breisch
2014-05-05 22:07 ` Chris J. Breisch
2014-05-05 22:29 ` Larry Hall (Cygwin)
2014-05-05 22:39 ` Chris J. Breisch
2014-05-06 0:43 ` Larry Hall (Cygwin)
2014-05-06 12:23 ` Chris J. Breisch
2014-05-05 22:09 ` Larry Hall (Cygwin)
2014-05-06 12:52 ` Microsoft Accounts (was Re: Problem with "None" Group on Non-Domain Members) Corinna Vinschen
2014-05-06 12:55 ` Corinna Vinschen
2014-05-06 13:01 ` Corinna Vinschen
2014-05-07 12:26 ` vlado99
2014-05-07 12:43 ` Corinna Vinschen
2014-05-06 17:01 ` Chris J. Breisch
2014-05-06 17:16 ` Corinna Vinschen
2014-05-06 18:22 ` Chris J. Breisch
2014-05-07 11:57 ` Corinna Vinschen
2014-05-07 12:40 ` Corinna Vinschen
2014-05-07 14:09 ` Chris J. Breisch
2014-05-07 14:46 ` Corinna Vinschen
2014-05-08 20:09 ` Corinna Vinschen
2014-05-08 23:18 ` Robert Pendell
2014-05-09 0:12 ` Ken Brown
2014-05-09 1:34 ` Robert Pendell
2014-05-09 6:11 ` Achim Gratz
2014-05-09 7:42 ` Corinna Vinschen
2014-05-07 14:05 ` Chris J. Breisch
2014-05-07 14:35 ` Corinna Vinschen [this message]
2014-05-07 14:05 ` Andrey Repin
2014-05-07 14:20 ` Corinna Vinschen
2014-05-07 14:43 ` Corinna Vinschen
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