svn commit: r184263 - head/sys/dev/drm

[Robert Noland]

Author: rnoland
Date: Sat Oct 25 16:29:28 2008
New Revision: 184263
URL: http://svn.freebsd.org/changeset/base/184263

Log:
  drm/i915: fix ioremap of a user address for non-root (CVE-2008-3831)
  
  Olaf Kirch noticed that the i915_set_status_page() function of the i915
  kernel driver calls ioremap with an address offset that is supplied by
  userspace via ioctl. The function zeroes the mapped memory via memset
  and tells the hardware about the address. Turns out that access to that
  ioctl is not restricted to root so users could probably exploit that to
  do nasty things. We haven't tried to write actual exploit code though.
  
  It only affects the Intel G33 series and newer.
  
  Approved by:	bz (secteam)
  Obtained from:	Intel drm repo
  Security:	CVE-2008-3831

Modified:
  head/sys/dev/drm/i915_dma.c

Modified: head/sys/dev/drm/i915_dma.c
==============================================================================
--- head/sys/dev/drm/i915_dma.c	Sat Oct 25 14:01:29 2008	(r184262)
+++ head/sys/dev/drm/i915_dma.c	Sat Oct 25 16:29:28 2008	(r184263)
@@ -1228,7 +1228,7 @@ struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_I915_GET_VBLANK_PIPE,  i915_vblank_pipe_get, DRM_AUTH ),
 	DRM_IOCTL_DEF(DRM_I915_VBLANK_SWAP, i915_vblank_swap, DRM_AUTH),
 	DRM_IOCTL_DEF(DRM_I915_MMIO, i915_mmio, DRM_AUTH),
-	DRM_IOCTL_DEF(DRM_I915_HWS_ADDR, i915_set_status_page, DRM_AUTH),
+	DRM_IOCTL_DEF(DRM_I915_HWS_ADDR, i915_set_status_page, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
 #ifdef I915_HAVE_BUFFER
 	DRM_IOCTL_DEF(DRM_I915_EXECBUFFER, i915_execbuffer, DRM_AUTH),
 #endif