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: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171115154913.23827-1-ville.syrjala@linux.intel.com
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 1a72883..34b5123 100644 (file)
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -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;
 

diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 5597a87..004db47 100644 (file)
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -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