Merge tag 'drm-fixes-2018-12-21' of git://anongit.freedesktop.org/drm/drm

torvalds · torvalds · commit 96d6ee7d2f81 · 2018-12-21T09:17:52.000-08:00
Pull final drm fix from Daniel Vetter:
 "Very calm week, so either everything perfect or everyone on holidays
  already. Just one array_index_nospec patch, also for stable"

* tag 'drm-fixes-2018-12-21' of git://anongit.freedesktop.org/drm/drm:
  drm/ioctl: Fix Spectre v1 vulnerabilities
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
@@ -37,6 +37,7 @@
 
 #include <linux/pci.h>
 #include <linux/export.h>
+#include <linux/nospec.h>
 
 /**
  * DOC: getunique and setversion story
@@ -800,13 +801,17 @@ long drm_ioctl(struct file *filp,
 
 	if (is_driver_ioctl) {
 		/* driver ioctl */
-		if (nr - DRM_COMMAND_BASE >= dev->driver->num_ioctls)
+		unsigned int index = nr - DRM_COMMAND_BASE;
+
+		if (index >= dev->driver->num_ioctls)
 			goto err_i1;
-		ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
+		index = array_index_nospec(index, dev->driver->num_ioctls);
+		ioctl = &dev->driver->ioctls[index];
 	} else {
 		/* core ioctl */
 		if (nr >= DRM_CORE_IOCTL_COUNT)
 			goto err_i1;
+		nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
 		ioctl = &drm_ioctls[nr];
 	}
 
@@ -888,6 +893,7 @@ bool drm_ioctl_flags(unsigned int nr, unsigned int *flags)
 
 	if (nr >= DRM_CORE_IOCTL_COUNT)
 		return false;
+	nr = array_index_nospec(nr, DRM_CORE_IOCTL_COUNT);
 
 	*flags = drm_ioctls[nr].flags;
 	return true;
