From 20943f984967477c906522112d2b6b5a29f94684 Mon Sep 17 00:00:00 2001
From: Matthew Auld <matthew.auld@intel.com>
Date: Wed, 2 May 2018 20:50:21 +0100
Subject: [PATCH] drm/i915/userptr: reject zero user_size
Git-commit: 20943f984967477c906522112d2b6b5a29f94684
Patch-mainline: v4.17-rc6
No-fix: c11c7bfd213495784b22ef82a69b6489f8d0092f
References: bsc#1051510

Operating on a zero sized GEM userptr object will lead to explosions.

Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl")
Testcase: igt/gem_userptr_blits/input-checking
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180502195021.30900-1-matthew.auld@intel.com
(cherry picked from commit c11c7bfd213495784b22ef82a69b6489f8d0092f)

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_gem_userptr.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -778,6 +778,9 @@ i915_gem_userptr_ioctl(struct drm_device
 			    I915_USERPTR_UNSYNCHRONIZED))
 		return -EINVAL;
 
+	if (!args->user_size)
+		return -EINVAL;
+
 	if (offset_in_page(args->user_ptr | args->user_size))
 		return -EINVAL;