On 19.09.2007 09:09, Alexander Larsson wrote:
On Tue, 2007-09-18 at 19:41 +0200, Thorsten Leemhuis wrote:
> Thus I'm not even able to read from it:
> $ dd if=/dev/sda3 bs=512K count=1 | strings
> dd: opening `/dev/sda3': Permission denied
> Life sucks, but that's how things are supposed to be in linux/unix land
> as far as I know. But well, for fuse there seem to exist different rules:
> $ mkdir ntfs
> $ /sbin/mount.ntfs-3g /dev/sda3 ntfs/
> $ touch ntfs/foo
> $ ls -l ntfs/foo
> -rwxrwxrwx 1 thl thl 0 18. Sep 19:27 ntfs/foo
> Which brings me to my questions: Can somebody please explain why the
> above it working? Does it mean that if I write my own malicious
> fuse.ext3 userspace driver that I can mount each and every block-device
> on my system and read or modify the files on it (all by using fuse)?
> What if there is a small error in mount.ntfs-3g somewhere -- could it be
> abused to destroy a partition on my system while being a ordinary user?
Thats quite weird. [...]
Agreed. But I got the impression that how some users expect it to work.
Is /sbin/mount.ntfs-3g setuid perhaps?
$ ls -l /sbin/mount.ntfs-3g
-rwsr-xr-- 1 root fuse 40528 26. Aug 16:50 /sbin/mount.ntfs-3g