From: Matthew Auld <matthew.auld@intel.com>
Date: Wed, 2 May 2018 19:50:21 +0000 (+0100)
Subject: drm/i915/userptr: reject zero user_size
X-Git-Tag: v3.16.60~66
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fd55b13e6434a47a82080e1b34b1b29cca8fe98e;p=linux

drm/i915/userptr: reject zero user_size

commit 20943f984967477c906522112d2b6b5a29f94684 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 3ac65a3c7124..ff290fc691c8 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -657,6 +657,9 @@ i915_gem_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file
 			    I915_USERPTR_UNSYNCHRONIZED))
 		return -EINVAL;
 
+	if (!args->user_size)
+		return -EINVAL;
+
 	if (offset_in_page(args->user_ptr | args->user_size))
 		return -EINVAL;