drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow

[net-next-2.6.git] / drivers / gpu / drm / i915 / i915_gem.c

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index bced9b25c71e2bc5819c3b02dfde055909937323..aa959c4a1836238354d7674cdaa52b3a195013d5 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -471,14 +471,17 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
                return -ENOENT;
        obj_priv = to_intel_bo(obj);
 
-       /* Bounds check source.
-        *
-        * XXX: This could use review for overflow issues...
-        */
-       if (args->offset > obj->size || args->size > obj->size ||
-           args->offset + args->size > obj->size) {
-               drm_gem_object_unreference_unlocked(obj);
-               return -EINVAL;
+       /* Bounds check source.  */
+       if (args->offset > obj->size || args->size > obj->size - args->offset) {
+               ret = -EINVAL;
+               goto err;
+       }
+
+       if (!access_ok(VERIFY_WRITE,
+                      (char __user *)(uintptr_t)args->data_ptr,
+                      args->size)) {
+               ret = -EFAULT;
+               goto err;
        }
 
        if (i915_gem_object_needs_bit17_swizzle(obj)) {
@@ -490,8 +493,8 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
                                                        file_priv);
        }
 
+err:
        drm_gem_object_unreference_unlocked(obj);
-
        return ret;
 }
 
@@ -580,8 +583,6 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev, struct drm_gem_object *obj,
 
        user_data = (char __user *) (uintptr_t) args->data_ptr;
        remain = args->size;
-       if (!access_ok(VERIFY_READ, user_data, remain))
-               return -EFAULT;
 
 
        mutex_lock(&dev->struct_mutex);
@@ -934,14 +935,17 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
                return -ENOENT;
        obj_priv = to_intel_bo(obj);
 
-       /* Bounds check destination.
-        *
-        * XXX: This could use review for overflow issues...
-        */
-       if (args->offset > obj->size || args->size > obj->size ||
-           args->offset + args->size > obj->size) {
-               drm_gem_object_unreference_unlocked(obj);
-               return -EINVAL;
+       /* Bounds check destination. */
+       if (args->offset > obj->size || args->size > obj->size - args->offset) {
+               ret = -EINVAL;
+               goto err;
+       }
+
+       if (!access_ok(VERIFY_READ,
+                      (char __user *)(uintptr_t)args->data_ptr,
+                      args->size)) {
+               ret = -EFAULT;
+               goto err;
        }
 
        /* We can only do the GTT pwrite on untiled buffers, as otherwise
@@ -975,8 +979,8 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
                DRM_INFO("pwrite failed %d\n", ret);
 #endif
 
+err:
        drm_gem_object_unreference_unlocked(obj);
-
        return ret;
 }
 
@@ -3258,6 +3262,8 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                                  (int) reloc->offset,
                                  reloc->read_domains,
                                  reloc->write_domain);
+                       drm_gem_object_unreference(target_obj);
+                       i915_gem_object_unpin(obj);
                        return -EINVAL;
                }
                if (reloc->write_domain & I915_GEM_DOMAIN_CPU ||