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Commit b080a9f0 authored by Sudarsan Ramesh's avatar Sudarsan Ramesh Committed by Gerrit - the friendly Code Review server
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disp: msm: dp: validate edid before dereferencing 



Currently, when using custom edid from debugfs, the
extensions data inside the edid block is not validated
before dereferencing the extension block.

The fix adds a edid validation function to validate
any custom edids before accessing any members in the
edid block.

Change-Id: I8a2cc45477416a8f8c4cff882bd53d14012e29f4
Signed-off-by: default avatarSudarsan Ramesh <sudarame@codeaurora.org>
parent c8a629f1

msm/dp/dp_debug.c

+2 −2
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ static ssize_t dp_debug_write_edid(struct file *file, 
	edid = debug->edid;

bail:

	kfree(buf);

	debug->panel->set_edid(debug->panel, edid);

	debug->panel->set_edid(debug->panel, edid, debug->edid_size);



	/*

	 * print edid status as this code is executed
@@ -1628,7 +1628,7 @@ static void dp_debug_set_sim_mode(struct dp_debug_private *debug, bool sim) 
		debug->aux->set_sim_mode(debug->aux, false, NULL, NULL);

		debug->dp_debug.sim_mode = false;



		debug->panel->set_edid(debug->panel, 0);

		debug->panel->set_edid(debug->panel, 0, 0);

		if (debug->edid) {

			devm_kfree(debug->dev, debug->edid);

			debug->edid = NULL;

msm/dp/dp_panel.c

+21 −2
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/unistd.h>

#include <drm/drm_fixed.h>

#include "dp_debug.h"

#include <drm/drm_edid.h>



#define DP_KHZ_TO_HZ 1000

#define DP_PANEL_DEFAULT_BPP 24
@@ -1937,7 +1938,25 @@ static int dp_panel_set_default_link_params(struct dp_panel *dp_panel) 
	return 0;

}



static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid)

static bool dp_panel_validate_edid(struct edid *edid, size_t edid_size)

{

	if (!edid || (edid_size < EDID_LENGTH))

		return false;



	if (EDID_LENGTH * (edid->extensions + 1) > edid_size) {

		DP_ERR("edid size does not match allocated.\n");

		return false;

	}



	if (!drm_edid_is_valid(edid)) {

		DP_ERR("invalid edid.\n");

		return false;

	}

	return true;

}



static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid,

		size_t edid_size)

{

	struct dp_panel_private *panel;
@@ -1948,7 +1967,7 @@ static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid) 


	panel = container_of(dp_panel, struct dp_panel_private, dp_panel);



	if (edid) {

	if (edid && dp_panel_validate_edid((struct edid *)edid, edid_size)) {

		dp_panel->edid_ctrl->edid = (struct edid *)edid;

		panel->custom_edid = true;

	} else {

msm/dp/dp_panel.h

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ struct dp_panel { 
	int (*get_modes)(struct dp_panel *dp_panel,

		struct drm_connector *connector, struct dp_display_mode *mode);

	void (*handle_sink_request)(struct dp_panel *dp_panel);

	int (*set_edid)(struct dp_panel *dp_panel, u8 *edid);

	int (*set_edid)(struct dp_panel *dp_panel, u8 *edid, size_t edid_size);

	int (*set_dpcd)(struct dp_panel *dp_panel, u8 *dpcd);

	int (*setup_hdr)(struct dp_panel *dp_panel,

		struct drm_msm_ext_hdr_metadata *hdr_meta,