From eb1e552524b40df2534f4046161658fd5c73cc63 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 26 Feb 2019 13:44:51 -0800 Subject: [PATCH] drm/vgem: fix use-after-free when drm_gem_handle_create() fails 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 Cc: Laura Abbott Cc: Daniel Vetter Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Acked-by: Laura Abbott Signed-off-by: Rodrigo Siqueira Link: https://patchwork.freedesktop.org/patch/msgid/20190226214451.195123-1-ebiggers@kernel.org Signed-off-by: Maxime Ripard Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vgem/vgem_drv.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index 6887db878b38..4709f08f39e4 100644 --- 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_create(struct drm_device *dev, 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,