Re: [syzbot] [hfs?] WARNING in hfs_write_inode

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hello!

On Thu, 2023-07-20 at 18:30 +0100, Matthew Wilcox wrote:
> On Thu, Jul 20, 2023 at 05:27:57PM +0200, Dmitry Vyukov wrote:
> > On Thu, 5 Jan 2023 at 17:45, Viacheslav Dubeyko <slava@dubeyko.com> wrote:
> > > > On Wed, Jan 04, 2023 at 08:37:16PM -0800, Viacheslav Dubeyko wrote:
> > > > > Also, as far as I can see, available volume in report (mount_0.gz) somehow corrupted already:
> > > > 
> > > > Syzbot generates deliberately-corrupted (aka fuzzed) filesystem images.
> > > > So basically, you can't trust anything you read from the disc.
> > > > 
> > > 
> > > If the volume has been deliberately corrupted, then no guarantee that file system
> > > driver will behave nicely. Technically speaking, inode write operation should never
> > > happened for corrupted volume because the corruption should be detected during
> > > b-tree node initialization time. If we would like to achieve such nice state of HFS/HFS+
> > > drivers, then it requires a lot of refactoring/implementation efforts. I am not sure that
> > > it is worth to do because not so many guys really use HFS/HFS+ as the main file
> > > system under Linux.
> > 
> > 
> > Most popular distros will happily auto-mount HFS/HFS+ from anything
> > inserted into USB (e.g. what one may think is a charger). This creates
> > interesting security consequences for most Linux users.
> > An image may also be corrupted non-deliberately, which will lead to
> > random memory corruptions if the kernel trusts it blindly.
> 
> Then we should delete the HFS/HFS+ filesystems.  They're orphaned in
> MAINTAINERS and if distros are going to do such a damnfool thing,
> then we must stop them.

Both HFS and HFS+ work perfectly fine. And if distributions or users are so
sensitive about security, it's up to them to blacklist individual features
in the kernel.

Both HFS and HFS+ have been the default filesystem on MacOS for 30 years
and I don't think it's justified to introduce such a hard compatibility
breakage just because some people are worried about theoretical evil
maid attacks.

HFS/HFS+ mandatory if you want to boot Linux on a classic Mac or PowerMac
and I don't think it's okay to break all these systems running Linux.

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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