On Mon, Jun 10, 2019 at 06:16:12PM -0700, Darrick J. Wong wrote:
> On Mon, Jun 10, 2019 at 08:26:06PM +0300, Amir Goldstein wrote:
> > read(2) is allowed from a swapfile, so copy_file_range(2) should
> > be allowed as well.
> >
> > Reported-by: Theodore Ts'o <tytso@xxxxxxx>
> > Fixes: 96e6e8f4a68d ("vfs: add missing checks to copy_file_range")
> > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > ---
> >
> > Darrick,
> >
> > This fixes the generic/554 issue reported by Ted.
>
> Frankly I think we should go the other way -- non-root doesn't get to
> copy from or read from swap files.
The issue is that without this patch, *root* doesn't get to copy from
swap files. Non-root shouldn't have access via Unix permissions. We
could add a special case if we don't trust system administrators to be
able to set the Unix permissions correctly, I suppose, but we don't do
that for block devices when they are mounted....
- Ted
