119c53d2d4
drm_gem_dumb_map_offset() now exists and does everything
vgem_gem_dump_map does and *ought* to do.
In particular, vgem_gem_dumb_map() was trying to reject mmapping an
imported dmabuf by checking the existence of obj->filp. Unfortunately,
we always allocated an obj->filp, even if unused for an imported dmabuf.
Instead, the drm_gem_dumb_map_offset(), since commit 90378e589192
("drm/gem: drm_gem_dumb_map_offset(): reject dma-buf"), uses the
obj->import_attach to reject such invalid mmaps.
This prevents vgem from allowing userspace mmapping the dumb handle and
attempting to incorrectly fault in remote pages belonging to another
device, where there may not even be a struct page.
v2: Use the default drm_gem_dumb_map_offset() callback
Fixes: af33a9190d02 ("drm/vgem: Enable dmabuf import interfaces")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> # v4.13+
Link: https://patchwork.freedesktop.org/patch/msgid/20200708154911.21236-1-chris@chris-wilson.co.uk
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.