| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 097/134] drm/vgem: fix use-after-free when drm_gem_handle_create() fails | Date | Mon, 1 Apr 2019 19:02:13 +0200 |
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4.19-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers <ebiggers@google.com>
commit 21d2b122732318b48c10b7262e15595ce54511d3 upstream.
If drm_gem_handle_create() fails in vgem_gem_create(), then the drm_vgem_gem_object is freed twice: once when the reference is dropped by drm_gem_object_put_unlocked(), and again by __vgem_gem_destroy().
This was hit by syzkaller using fault injection.
Fix it by skipping the second free.
Reported-by: syzbot+e73f2fb5ed5a5df36d33@syzkaller.appspotmail.com Fixes: af33a9190d02 ("drm/vgem: Enable dmabuf import interfaces") Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Laura Abbott <labbott@redhat.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190226214451.195123-1-ebiggers@kernel.org Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/gpu/drm/vgem/vgem_drv.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
--- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -191,13 +191,9 @@ static struct drm_gem_object *vgem_gem_c ret = drm_gem_handle_create(file, &obj->base, handle); drm_gem_object_put_unlocked(&obj->base); if (ret) - goto err; + return ERR_PTR(ret); return &obj->base; - -err: - __vgem_gem_destroy(obj); - return ERR_PTR(ret); } static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
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