Can't combine -o permissions with -o uid=UUU,gid=GGG
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
ntfs-3g (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
At the moment, it seems that mount.ntfs-3g disables -o permissions if -o uid=UUU and/or uid=GGG are also specified. This (combined with Ubuntu's compilation options disallowing user mounts for NTFS-3g) prevents unprivileged users from easily accessing NTFS systems while preserving standard Unix permissions.
root# mount -o uid=500,
root# touch /vol/exthd/x
root# ls -al /vol/exthd/x
-rwxrwxrwx 1 muresan muresan 0 Dec 8 00:29 /vol/exthd/x
root# chmod u-x /vol/exthd/x
root# ls -al /vol/exthd/x
-rwxrwxrwx 1 muresan muresan 0 Dec 8 00:29 /vol/exthd/x
So chmod is ignored and all permissions are fixed to rwx.
With "mount -o permissions", permissions ARE preserved, but all files are owned by root:
root# mount -o permissions /dev/sdb1 /vol/exthd
Using default user mapping
root# touch /vol/exthd/x
root# ls -al /vol/exthd/x
-rw--w--w- 1 root root 0 Dec 8 00:29 /vol/exthd/x
root# chmod u+x /vol/exthd/x
root# ls -al /vol/exthd/x
-rwx-w--w- 1 root root 0 Dec 8 00:29 /vol/exthd/x
root# rm /vol/exthd/x
root# ls -al /bin/bash
-rwxr-xr-x 1 root root 920788 Apr 3 2012 /bin/bash
root# cp -a /bin/bash /vol/exthd/
root# ls -al /vol/exthd/bash
-rwxr-xr-x 1 root root 920788 Apr 3 2012 /vol/exthd/bash
root# umount /vol/exthd
Trying to mount the filesystem as an unprivileged user results in:
Either mount the volume as root, or rebuild NTFS-3G with integrated
FUSE support and make it setuid root. Please see more information at
http://
Note, my shell log shows the behavior with mount -o uid=500, gid=500, umask=000. The same behavior (chmod has no effect) occurs when using mount -o permissions, uid=500, gid=500, umask=000 (as if -o permissions is being silently ignored).