umask equivalent for ext2/ext3 filesystems

Message

tom_bxl · Post by **tom_bxl** » Mon Apr 09, 2007 8:10 am

Hi,

I would like to set a default umask to something like 220 on ext2 and ext3 file systems. Looking at the man page for mount, I could only find these options for several file system types but not on ext2/3. Is this possible and how?

Thanks,

Tom

suicidal_orange_II · Post by **suicidal_orange_II** » Mon Apr 09, 2007 1:49 pm

I'm not 100% sure on this but I think the root of the partition takes on the permission of the folder it's mounted to. Are you trying to make it that no files on the partition can be executed? You can do that by

Code: Select all

mount -o noexec /dev/whatever /wherever

or by adding it to your fstab.

Hope I didn't totally misunderstand what you wanted

Suicidal_Orange

tom_bxl · Post by **tom_bxl** » Mon Apr 09, 2007 6:26 pm

Thanks for the try

; but it does not seem to work. I have tried to change the permissions to 770 on the mount point before mounting it, but after I mounted the file system on it, the permissions were changed to 755.

In a shameless attempt, I also tried to set the default permissions to 770 changing the udev rules on the device /dev/sdax and I got the same result after mounting the file system.

Thanks anyway for the answer.

Tom

tom_bxl · Post by **tom_bxl** » Mon Apr 09, 2007 6:32 pm

Btw, if my first post was not clear. I'm using the option grpid to force any file/directory created to inherit the group from its parent directory (which works fine), but I now would like to manage the default permissions (currently similar to using a umask 022) to umask 002.

Tom

eccerr0r · Post by **eccerr0r** » Mon Apr 09, 2007 6:50 pm

I don't think the functionality exists because of the fact that mode bits can be changed on a per-file basis unlike msdos filesystems, which doesn't have the capability...

What specifically are you trying to do? Is this a hotplug disk?

Are you trying to use this as a workgroup disk?

You could try just chmod -R to fix all the permissions, set the setgid bit to prevent further group write issues, make sure all the group owners are correct, and make sure everyone's .profile contains the correct umask default...

Another possibility is to go beyond ugo and use the newer ACL system?

You don't want to change the permissions on the /dev/sdXX device file, that should only be readable/writeable by root.

tom_bxl · Post by **tom_bxl** » Tue Apr 10, 2007 12:01 pm

eccerr0r wrote:I don't think the functionality exists because of the fact that mode bits can be changed on a per-file basis unlike msdos filesystems, which doesn't have the capability...

Makes sense

eccerr0r wrote: What specifically are you trying to do? Is this a hotplug disk?

Are you trying to use this as a workgroup disk?

The disk is a normal hard drive. I'm indeed trying to share a directory and all sub-dirs/files between several users on the same PC. No need for network access. All files under this directory should have read/write access to all users belonging to a given group. I would like this by default so users would not have to manually change perimisisons each time they create a file.

eccerr0r wrote: You could try just chmod -R to fix all the permissions, set the setgid bit to prevent further group write issues, make sure all the group owners are correct, and make sure everyone's .profile contains the correct umask default...

I don't really like this option. If I'm not mistaken, forcing the umask in everyone's profile will change the default permissions for every file newly created. I just want to limit this behavior to a filesystem.

eccerr0r wrote: Another possibility is to go beyond ugo and use the newer ACL system?

I'll give a look to ACL

eccerr0r wrote: You don't want to change the permissions on the /dev/sdXX device file, that should only be readable/writeable by root.

Good point, I have reverted back the changes, this was just for testing.