diff options
| author | Steve Cohen <cohens@codeaurora.org> | 2020-07-20 18:30:50 -0400 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2020-07-27 22:05:51 +0200 |
| commit | 8490d6a7e0a0a6fab5c2d82d57a3937306660864 (patch) | |
| tree | 4c48fca4801198cf553f3ec0438fb069a6516615 | |
| parent | 900ab59e2621053b009f707f80b2c19ce0af5dee (diff) | |
| download | linux-8490d6a7e0a0a6fab5c2d82d57a3937306660864.tar.bz2 | |
drm: hold gem reference until object is no longer accessed
A use-after-free in drm_gem_open_ioctl can happen if the
GEM object handle is closed between the idr lookup and
retrieving the size from said object since a local reference
is not being held at that point. Hold the local reference
while the object can still be accessed to fix this and
plug the potential security hole.
Signed-off-by: Steve Cohen <cohens@codeaurora.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1595284250-31580-1-git-send-email-cohens@codeaurora.org
| -rw-r--r-- | drivers/gpu/drm/drm_gem.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 7bf628e13023..ee2058ad482c 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -871,9 +871,6 @@ err: * @file_priv: drm file-private structure * * Open an object using the global name, returning a handle and the size. - * - * This handle (of course) holds a reference to the object, so the object - * will not go away until the handle is deleted. */ int drm_gem_open_ioctl(struct drm_device *dev, void *data, @@ -898,14 +895,15 @@ drm_gem_open_ioctl(struct drm_device *dev, void *data, /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */ ret = drm_gem_handle_create_tail(file_priv, obj, &handle); - drm_gem_object_put_unlocked(obj); if (ret) - return ret; + goto err; args->handle = handle; args->size = obj->size; - return 0; +err: + drm_gem_object_put_unlocked(obj); + return ret; } /** |