This is the mail archive of the cygwin mailing list for the Cygwin project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
Corinna Vinschen wrote:
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.On May 6 14:22, Chris J. Breisch wrote:Corinna Vinschen wrote:On Windows, users and groups are identified not by uid/gid, but by their SID. The SID is a unique value, but other than that, a SID can be a user or a group and in lots of cases Windows doesn't care. A group can be owner of a file and a user can be the group of the file, it just doesn't matter to Windows. The permission "problem" you're seeing is a result of that. Your user *and* your primary group are both your user's SID. Therefore the same account is user and primary group at the same time. Therefore, if the file is created, it gets created with an ACL with user and group being the same account. Therefore the POSIX translation of the user and group permissions on the file are always the same. Does this clear it up?Yes, that makes complete sense. Thank you again.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.
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.
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? Seems like I need to get some more caffeine and go back and reread your attached document from several messages ago.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.
Thoughts? Corinna
-- Chris J. Breisch -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |