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Commit c6ed6dad authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/uapi: Validate the mode flags/type 



Currently userspace is allowed to feed in any king of garbage in the
high bits of the mode flags/type, as are drivers when probing modes.
Reject any mode with bogus flags/type.

Hopefully this won't break any current userspace...

v2: Split the type and flags checks to separates ifs (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Adam Jackson <ajax@redhat.com>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarAdam Jackson <ajax@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171115154913.23827-1-ville.syrjala@linux.intel.com


Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 064a3e6e

drivers/gpu/drm/drm_modes.c

+6 −0
Original line number Diff line number Diff line
@@ -1036,6 +1036,12 @@ EXPORT_SYMBOL(drm_mode_equal_no_clocks_no_stereo); 
enum drm_mode_status

drm_mode_validate_basic(const struct drm_display_mode *mode)

{

	if (mode->type & ~DRM_MODE_TYPE_ALL)

		return MODE_BAD;



	if (mode->flags & ~DRM_MODE_FLAG_ALL)

		return MODE_BAD;



	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) > DRM_MODE_FLAG_3D_MAX)

		return MODE_BAD;

include/uapi/drm/drm_mode.h

+24 −0
Original line number Diff line number Diff line
@@ -46,6 +46,14 @@ extern "C" { 
#define DRM_MODE_TYPE_USERDEF	(1<<5)

#define DRM_MODE_TYPE_DRIVER	(1<<6)



#define DRM_MODE_TYPE_ALL	(DRM_MODE_TYPE_BUILTIN |	\

				 DRM_MODE_TYPE_CLOCK_C |	\

				 DRM_MODE_TYPE_CRTC_C |		\

				 DRM_MODE_TYPE_PREFERRED |	\

				 DRM_MODE_TYPE_DEFAULT |	\

				 DRM_MODE_TYPE_USERDEF |	\

				 DRM_MODE_TYPE_DRIVER)



/* Video mode flags */

/* bit compatible with the xrandr RR_ definitions (bits 0-13)

 *
@@ -99,6 +107,22 @@ extern "C" { 
#define  DRM_MODE_FLAG_PIC_AR_16_9 \

			(DRM_MODE_PICTURE_ASPECT_16_9<<19)



#define  DRM_MODE_FLAG_ALL	(DRM_MODE_FLAG_PHSYNC |		\

				 DRM_MODE_FLAG_NHSYNC |		\

				 DRM_MODE_FLAG_PVSYNC |		\

				 DRM_MODE_FLAG_NVSYNC |		\

				 DRM_MODE_FLAG_INTERLACE |	\

				 DRM_MODE_FLAG_DBLSCAN |	\

				 DRM_MODE_FLAG_CSYNC |		\

				 DRM_MODE_FLAG_PCSYNC |		\

				 DRM_MODE_FLAG_NCSYNC |		\

				 DRM_MODE_FLAG_HSKEW |		\

				 DRM_MODE_FLAG_BCAST |		\

				 DRM_MODE_FLAG_PIXMUX |		\

				 DRM_MODE_FLAG_DBLCLK |		\

				 DRM_MODE_FLAG_CLKDIV2 |	\

				 DRM_MODE_FLAG_3D_MASK)



/* DPMS flags */

/* bit compatible with the xorg definitions. */

#define DRM_MODE_DPMS_ON	0