Re: [PATCH] ntfs: Ensure $Extend is a directory

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Jul 25, 2022 at 12:06:56PM -0700, Soumya Negi wrote:
> Hi,
> 
> On Sun, Jul 24, 2022 at 03:17:45PM -0700, Soumya Negi wrote:
> > On Sun, Jul 24, 2022 at 05:54:43PM +0200, Greg KH wrote:
> > > On Sun, Jul 24, 2022 at 08:34:48AM -0700, Soumya Negi wrote:
> > > > On Sun, Jul 24, 2022 at 03:47:01PM +0200, Greg KH wrote:
> > > > > On Sun, Jul 24, 2022 at 06:21:07AM -0700, Soumya Negi wrote:
> > > > > > Fixes Syzbot bug: kernel BUG in ntfs_lookup_inode_by_name
> > > > > > https://syzkaller.appspot.com/bug?id=32cf53b48c1846ffc25a185a2e92e170d1a95d71
> > > > > > 
> > > > > > Check whether $Extend is a directory or not( for NTFS3.0+) while loading
> > > > > > system files. If it isn't(as in the case of this bug where the mft record for
> > > > > > $Extend contains a regular file), load_system_files() returns false.
> > > > > 
> > > > > Please wrap your changelog text at 72 columns like your editor asked you
> > > > > to when writing this :)
> > > > 
> > > > I will correct the changelog(Don't think I can wrap the bug report
> > > > link. Checkpatch will still give a warning. Is that okay?).
> > > 
> > > Yes, do not wrap links.
> > > 
> > > > > > Reported-by: syzbot+30b7f850c6d98ea461d2@syzkaller.appspotmail.com
> > > > > > Signed-off-by: Soumya Negi <soumya.negi97@gmail.com>
> > > > > 
> > > > > What commit caused this problem?  What Fixes: tag should go here?
> > > > 
> > > > I don't think this was caused by any specific commit.The $Extend
> > > > directory check is not present in any previous releases. Syzbot has
> > > > also not been able to produce a cause bisection for the bug. So no fixes
> > > > tag(please correct me if I am wrong).
> > > > 
> > > > > Should it go to stable kernels?  If so, how far back?
> > > > 
> > > > Since the NTFS extension file was new to NTFS 3.0, perhaps the patch 
> > > > should apply all the way back to the first release with NTFS3.0 support?
> > 
> > > Yes, mark it there.
> > 
> > Thanks. I will send v2 of the patch. Just want to make sure that the
> > patch will apply to 2.6.11.y before marking it.
> 
> 2.6.11 is where I think NTFS3.0 support was first present and till where
> the patch should go. But I am not able to build 2.6.11 on my system and
> test the patch. I tried the patch on 4.14 and it works. Should I mark it
> to be backported till 4.14 instead?

Say 4.9 and you will get an email saying it failed to apply there when
it gets merged into Linus's tree, and then you can provide a working
patch for us to add to stable.

thanks,

greg k-h