From: Tony Finch <dot@dotat.at>
To: arnold@skeeve.com
Cc: tuhs@tuhs.org, doug@cs.dartmouth.edu
Subject: Re: [TUHS] Additional groups and additional directory permissions
Date: Fri, 2 Aug 2019 12:18:30 +0100 [thread overview]
Message-ID: <alpine.DEB.2.20.1908021139530.11612@grey.csi.cam.ac.uk> (raw)
In-Reply-To: <201908020835.x728ZUal026532@freefriends.org>
arnold@skeeve.com <arnold@skeeve.com> wrote:
> Arthur Krewat <krewat@kilonet.net>:
> > There's also the setgid bit on directories, that when files are created,
> > they will be in the group that the parent directory has on it.
>
> IIRC this was a Sun invention. It was in SunOS 4.x, and may even have
> been in SunOS 3.x.
When Bill Joy added the "multi-group stuff" to BSD all directories became
implicitly set-gid:
https://svnweb.freebsd.org/csrg/sys/ufs/ffs/ffs_inode.c?r1=4818&r2=5855
This is in SCCS revision 4.8 so I think it appeared in 4.2BSD
As I understand it, when group support was improved in System V they did
not change creat() to match BSD but instead used the directory set-gid bit
to provide opt-in BSD semantics. I don't know if this was in Solaris or
earlier?
> > Also, I don't think it's been mentioned, but there's the setuid bit on
> > directories - otherwise known as the sticky bit. When set, even if you
> > have rights to "write" the directory (meaning, delete files), you can't
> > delete those owned by other users. Useful for /tmp
>
> Also a SunOS invention, IIRC.
BSD again :-) SCCS revision 6.6 so I think it appeared in 4.3BSD
https://svnweb.freebsd.org/csrg/sys/ufs/ffs/ufs_lookup.c?r1=15809&r2=16046
Tony.
--
f.anthony.n.finch <dot@dotat.at> http://dotat.at/
Mull of Galloway to Mull of Kintyre including the Firth of Clyde and North
Channel: Variable 1 to 3, becoming easterly or southeasterly 2 to 4 later.
Smooth, occasionally slight at first in North Channel. Showers for a time near
shore. Good.
next prev parent reply other threads:[~2019-08-02 11:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 12:35 [TUHS] Who's behind the UNIX filesystem permission Doug McIlroy
2019-08-01 16:22 ` John P. Linderman
2019-08-01 16:35 ` Arthur Krewat
2019-08-02 8:35 ` [TUHS] Additional groups and additional directory permissions arnold
2019-08-02 11:18 ` Tony Finch [this message]
2019-08-04 6:40 ` arnold
2019-08-02 12:45 ` Arthur Krewat
2019-08-02 13:06 ` Clem Cole
2019-08-02 13:28 ` Clem Cole
2019-08-02 19:00 ` Thomas Paulsen
2019-08-01 17:01 ` [TUHS] Who's behind the UNIX filesystem permission Nemo Nusquam
2019-08-01 18:26 ` Arthur Krewat
2019-08-01 20:14 ` Lyndon Nerenberg
2019-08-01 21:23 ` Dave Horsfall
2019-08-02 19:44 [TUHS] Additional groups and additional directory permissions Norman Wilson
2019-08-10 4:02 Kirk McKusick
2019-08-10 6:02 ` Thomas Paulsen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.20.1908021139530.11612@grey.csi.cam.ac.uk \
--to=dot@dotat.at \
--cc=arnold@skeeve.com \
--cc=doug@cs.dartmouth.edu \
--cc=tuhs@tuhs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).