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* [PATCH] drm/i915/bios: range check LFP Data Block panel_type2
@ 2026-06-25 13:51 Jani Nikula
  2026-06-25 15:27 ` Michał Grzelak
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Jani Nikula @ 2026-06-25 13:51 UTC (permalink / raw)
  To: intel-gfx, intel-xe
  Cc: jani.nikula, Martin Hodo, stable, Animesh Manna,
	Ville Syrjälä

While the panel_type from LFP Data Block is range checked, panel_type2
is not. Add a few helpers for range checking, and use them to not only
check panel_type2, but also imrove clarity and correctness in the panel
type selection.

Discovered using AI-assisted static analysis confirmed by Intel Product
Security.

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: 6434cf630086 ("drm/i915/bios: calculate panel type as per child device index in VBT")
Cc: <stable@vger.kernel.org> # v6.0+
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Ville Syrjälä <ville.syrjala@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c | 29 +++++++++++++++++------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 15ebadc72b88..0c420019e46a 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -623,6 +623,16 @@ get_lfp_data_tail(const struct bdb_lfp_data *data,
 		return NULL;
 }
 
+static bool is_panel_type_valid(int panel_type)
+{
+	return panel_type >= 0 && panel_type < 16;
+}
+
+static bool is_panel_type_valid_or_pnp(int panel_type)
+{
+	return is_panel_type_valid(panel_type) || panel_type == 0xff;
+}
+
 static int opregion_get_panel_type(struct intel_display *display,
 				   const struct intel_bios_encoder_data *devdata,
 				   const struct drm_edid *drm_edid, bool use_fallback)
@@ -640,15 +650,21 @@ static int vbt_get_panel_type(struct intel_display *display,
 	if (!lfp_options)
 		return -1;
 
-	if (lfp_options->panel_type > 0xf &&
-	    lfp_options->panel_type != 0xff) {
+	if (!is_panel_type_valid_or_pnp(lfp_options->panel_type)) {
 		drm_dbg_kms(display->drm, "Invalid VBT panel type 0x%x\n",
 			    lfp_options->panel_type);
 		return -1;
 	}
 
-	if (devdata && devdata->child.handle == DEVICE_HANDLE_LFP2)
+	if (devdata && devdata->child.handle == DEVICE_HANDLE_LFP2) {
+		if (!is_panel_type_valid_or_pnp(lfp_options->panel_type2)) {
+			drm_dbg_kms(display->drm, "Invalid VBT panel type 2 0x%x\n",
+				    lfp_options->panel_type2);
+			return -1;
+		}
+
 		return lfp_options->panel_type2;
+	}
 
 	drm_WARN_ON(display->drm,
 		    devdata && devdata->child.handle != DEVICE_HANDLE_LFP1);
@@ -762,13 +778,12 @@ static int get_panel_type(struct intel_display *display,
 				    panel_types[i].name, panel_types[i].panel_type);
 	}
 
-	if (panel_types[PANEL_TYPE_OPREGION].panel_type >= 0)
+	if (is_panel_type_valid(panel_types[PANEL_TYPE_OPREGION].panel_type))
 		i = PANEL_TYPE_OPREGION;
 	else if (panel_types[PANEL_TYPE_VBT].panel_type == 0xff &&
-		 panel_types[PANEL_TYPE_PNPID].panel_type >= 0)
+		 is_panel_type_valid(panel_types[PANEL_TYPE_PNPID].panel_type))
 		i = PANEL_TYPE_PNPID;
-	else if (panel_types[PANEL_TYPE_VBT].panel_type != 0xff &&
-		 panel_types[PANEL_TYPE_VBT].panel_type >= 0)
+	else if (is_panel_type_valid(panel_types[PANEL_TYPE_VBT].panel_type))
 		i = PANEL_TYPE_VBT;
 	else
 		i = PANEL_TYPE_FALLBACK;
-- 
2.47.3


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-06-26 14:02 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-06-25 13:51 [PATCH] drm/i915/bios: range check LFP Data Block panel_type2 Jani Nikula
2026-06-25 15:27 ` Michał Grzelak
2026-06-25 18:58 ` ✓ i915.CI.BAT: success for " Patchwork
2026-06-26  1:38 ` ✗ i915.CI.Full: failure " Patchwork
2026-06-26 13:37 ` [PATCH] " Ville Syrjälä
2026-06-26 14:01 ` [PATCH v2] " Jani Nikula

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