drm/r128: Add test for initialisation to all ioctls that require it

Almost all r128's private ioctls require that the CCE state has
already been initialised.  However, most do not test that this has
been done, and will proceed to dereference a null pointer.  This may
result in a security vulnerability, since some ioctls are
unprivileged.

This adds a macro for the common initialisation test and changes all
ioctl implementations that require prior initialisation to use that
macro.

Also, r128_do_init_cce() does not test that the CCE state has not
been initialised already.  Repeated initialisation may lead to a crash
or resource leak.  This adds that test.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/r128/r128_cce.c b/drivers/gpu/drm/r128/r128_cce.c
index 15252f6..4c39a40 100644
--- a/drivers/gpu/drm/r128/r128_cce.c
+++ b/drivers/gpu/drm/r128/r128_cce.c
@@ -346,6 +346,11 @@
 
 	DRM_DEBUG("\n");
 
+	if (dev->dev_private) {
+		DRM_DEBUG("called when already initialized\n");
+		return -EINVAL;
+	}
+
 	dev_priv = kzalloc(sizeof(drm_r128_private_t), GFP_KERNEL);
 	if (dev_priv == NULL)
 		return -ENOMEM;
@@ -647,6 +652,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	if (dev_priv->cce_running || dev_priv->cce_mode == R128_PM4_NONPM4) {
 		DRM_DEBUG("while CCE running\n");
 		return 0;
@@ -669,6 +676,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	/* Flush any pending CCE commands.  This ensures any outstanding
 	 * commands are exectuted by the engine before we turn it off.
 	 */
@@ -706,10 +715,7 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
-	if (!dev_priv) {
-		DRM_DEBUG("called before init done\n");
-		return -EINVAL;
-	}
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
 
 	r128_do_cce_reset(dev_priv);
 
@@ -726,6 +732,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	if (dev_priv->cce_running) {
 		r128_do_cce_flush(dev_priv);
 	}
@@ -739,6 +747,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev->dev_private);
+
 	return r128_do_engine_reset(dev);
 }
 
diff --git a/drivers/gpu/drm/r128/r128_drv.h b/drivers/gpu/drm/r128/r128_drv.h
index 797a26c..3c60829 100644
--- a/drivers/gpu/drm/r128/r128_drv.h
+++ b/drivers/gpu/drm/r128/r128_drv.h
@@ -422,6 +422,14 @@
  * Misc helper macros
  */
 
+#define DEV_INIT_TEST_WITH_RETURN(_dev_priv)				\
+do {									\
+	if (!_dev_priv) {						\
+		DRM_ERROR("called with no initialization\n");		\
+		return -EINVAL;						\
+	}								\
+} while (0)
+
 #define RING_SPACE_TEST_WITH_RETURN( dev_priv )				\
 do {									\
 	drm_r128_ring_buffer_t *ring = &dev_priv->ring; int i;		\
diff --git a/drivers/gpu/drm/r128/r128_state.c b/drivers/gpu/drm/r128/r128_state.c
index 026a48c..af2665c 100644
--- a/drivers/gpu/drm/r128/r128_state.c
+++ b/drivers/gpu/drm/r128/r128_state.c
@@ -1244,14 +1244,18 @@
 static int r128_cce_clear(struct drm_device *dev, void *data, struct drm_file *file_priv)
 {
 	drm_r128_private_t *dev_priv = dev->dev_private;
-	drm_r128_sarea_t *sarea_priv = dev_priv->sarea_priv;
+	drm_r128_sarea_t *sarea_priv;
 	drm_r128_clear_t *clear = data;
 	DRM_DEBUG("\n");
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	RING_SPACE_TEST_WITH_RETURN(dev_priv);
 
+	sarea_priv = dev_priv->sarea_priv;
+
 	if (sarea_priv->nbox > R128_NR_SAREA_CLIPRECTS)
 		sarea_priv->nbox = R128_NR_SAREA_CLIPRECTS;
 
@@ -1312,6 +1316,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	RING_SPACE_TEST_WITH_RETURN(dev_priv);
 
 	if (!dev_priv->page_flipping)
@@ -1331,6 +1337,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	RING_SPACE_TEST_WITH_RETURN(dev_priv);
 
 	if (sarea_priv->nbox > R128_NR_SAREA_CLIPRECTS)
@@ -1354,10 +1362,7 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
-	if (!dev_priv) {
-		DRM_ERROR("called with no initialization\n");
-		return -EINVAL;
-	}
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
 
 	DRM_DEBUG("pid=%d index=%d count=%d discard=%d\n",
 		  DRM_CURRENTPID, vertex->idx, vertex->count, vertex->discard);
@@ -1410,10 +1415,7 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
-	if (!dev_priv) {
-		DRM_ERROR("called with no initialization\n");
-		return -EINVAL;
-	}
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
 
 	DRM_DEBUG("pid=%d buf=%d s=%d e=%d d=%d\n", DRM_CURRENTPID,
 		  elts->idx, elts->start, elts->end, elts->discard);
@@ -1476,6 +1478,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	DRM_DEBUG("pid=%d index=%d\n", DRM_CURRENTPID, blit->idx);
 
 	if (blit->idx < 0 || blit->idx >= dma->buf_count) {
@@ -1501,6 +1505,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	RING_SPACE_TEST_WITH_RETURN(dev_priv);
 
 	ret = -EINVAL;
@@ -1531,6 +1537,8 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
+
 	if (DRM_COPY_FROM_USER(&mask, stipple->mask, 32 * sizeof(u32)))
 		return -EFAULT;
 
@@ -1555,10 +1563,7 @@
 
 	LOCK_TEST_WITH_RETURN(dev, file_priv);
 
-	if (!dev_priv) {
-		DRM_ERROR("called with no initialization\n");
-		return -EINVAL;
-	}
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
 
 	DRM_DEBUG("idx=%d s=%d e=%d d=%d\n",
 		  indirect->idx, indirect->start, indirect->end,
@@ -1620,10 +1625,7 @@
 	drm_r128_getparam_t *param = data;
 	int value;
 
-	if (!dev_priv) {
-		DRM_ERROR("called with no initialization\n");
-		return -EINVAL;
-	}
+	DEV_INIT_TEST_WITH_RETURN(dev_priv);
 
 	DRM_DEBUG("pid=%d\n", DRM_CURRENTPID);