Messages in this thread |  | | | Date | Tue, 28 Aug 2001 12:18:47 +0100 | | From | Jamie Lokier <> | | Subject | Re: [PATCH] Ext2FS: SUID on Dir |
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Clifford Wolf wrote: > But that only makes sense if the umask is set to give full permissions to > the group (e.g. 007 or 002). Noone would do that if there is a system-wide > 'users' group - so some distributions add an extra group for every user > which lets the /etc/group file grow very fast and makes the admins life > harder ...
Concured. In my experience, "extra group for every user" doesn't work with you're sharing over NFS with systems that don't use it. Which means using a umask of 022 or 077, and that renders the SGID-directory feature almost useless.
I've seen two problems result from this: user files created group writable on the NFS server, when they should not be (a security problem). And shared directories created non-group-writable, which other group members cannot fix. (Only root can fix this).
For example where I work, some of the CVS directories cannot be checked out because some directories, which should be group writable, are not.
> The following small patch adds a function to the SUID flag on directories. > If the SUID flag is set for a diectory, all new files in that directory > will get the same rights in the group-field as they have in their > user-field.
Your patch does not fix the problem with CVS directories. In those, directories need to be writable, but newly created user files should not necessarily be group writable.
So I would suggest this behaviour:
sgid directory -> new subdirectories copy group umask from user umask suid directory -> new non-directories copy group umask from user umask
Both these behaviours would be enabled by a mount option, preferably a generic one.
cheers, -- Jamie - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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