On 19.09.2007 09:51, Alexander Larsson wrote:
On Wed, 2007-09-19 at 09:38 +0200, Thorsten Leemhuis wrote:
> 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
Oh. That seems like a bad idea to me.
I tried to discuss the issue with spot (the ntfs-3g maintainer) in
#fedora-devel but he was busy and he asked me to file a bug, which I