Is NTFS-3G compiled with support for FUSE?

English Hardware
#1

Hi, this is just to verify if I’m doing something wrong.

I have a 3TB disk installed (SATA, no USB) which was formatted under Windows. The NTFS partition is available as /dev/sdb2. The /etc/fstab entry looks like this:

/dev/sdb2 /mnt/av ntfs-3g noauto,mand,relatime,user,locale=de_DE.utf8 0 0

I have been able to mount the partition as root simply by typing mount /mnt/av, created the .NTFS-3G directory, and copied over the file UserMapping to that directory. So far, so good.

Now I want to mount the partition as user.

First attempt:

$ mount -o rw,big_writes,norecover,streams_interface=windows,windows_names /mnt/av
Mount is denied because setuid and setgid root ntfs-3g is insecure with the external 
FUSE library. Either remove the setuid/setgid bit from the binary or rebuild NTFS-3G 
with integrated FUSE support and  make it setuid root.
Please see more information at
https://github.com/tuxera/ntfs-3g/wiki/NTFS-3G-FAQ

So I checked the FAQ:

Unprivileged block device mounts work only if all the below requirements are met:
1. ntfs-3g is compiled with integrated FUSE support
2. the ntfs-3g binary is at least version 1.2506
3. the ntfs-3g binary is set to setuid-root
4. the user has access right to the volume
5. the user has access right to the mount point

Nr. 2 and 5 are fulfilled. So I followed the advice for Nr. 3 & 4:

# usermod -aG disk userA
# which ntfs-3g
/usr/bin/ntfs-3g
# chown root:disk /usr/bin/ntfs-3g
# chmod 4750 /usr/bin/ntfs-3g

Now the mount command no longer throws an error message. However, the partition still is not accessible, ls shows no output.

$ mount -o rw,big_writes,norecover,streams_interface=windows,windows_names /mnt/av
$ ls -al /mnt/av
$

So before I start to compile NTFS-3G I would like to get confirmation that the executable that comes with Tumbleweed lacks FUSE support. Do you know?

Thanks

#2

After consulting the ntfs-3g README, it looks like the binary in the distribution’s package has no external FUSE support. The default is to use the fuse kernel module. The README states:

“Please note that NTFS-3G doesn’t require the FUSE user space package any more.”

and

“Below are a few specific options to ./configure :
…
–with-fuse=external : use external fuse (overriding Linux default)”

The wiki page states:

“If ntfs-3g is set setuid-root then non-root users will be also able to mount volumes.”

It seems that they failed to mention that mounting as normal user only works with the external fuse but not with the default kernel module.

As I can get the partition mounted simply by prepending sudo, I don’t think it makes sense to spend more time on this.

This works:

$ sudo mount -o rw,big_writes,norecover,streams_interface=windows,windows_names /mnt/av

So this seems to be a documentation flaw.