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Commit 8504072a authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Dave Airlie
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drm: edid: Add bounds checking to HDMI VSDB parsing



The length of HDMI VSDB must be at least 5 bytes. Other than the minimum,
nothing else about the length is specified. Check the length before
accessing any additional field beyond the minimum length.

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarAdam Jackson <ajax@redhat.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 9e50b9d5
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+21 −12
Original line number Diff line number Diff line
@@ -1576,18 +1576,27 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
}

static void
parse_hdmi_vsdb(struct drm_connector *connector, uint8_t *db)
parse_hdmi_vsdb(struct drm_connector *connector, const u8 *db)
{
	connector->eld[5] |= (db[6] >> 7) << 1;  /* Supports_AI */
	u8 len = cea_db_payload_len(db);

	if (len >= 6) {
		connector->eld[5] |= (db[6] >> 7) << 1;  /* Supports_AI */
		connector->dvi_dual = db[6] & 1;
	}
	if (len >= 7)
		connector->max_tmds_clock = db[7] * 5;

	if (len >= 8) {
		connector->latency_present[0] = db[8] >> 7;
		connector->latency_present[1] = (db[8] >> 6) & 1;
	}
	if (len >= 9)
		connector->video_latency[0] = db[9];
	if (len >= 10)
		connector->audio_latency[0] = db[10];
	if (len >= 11)
		connector->video_latency[1] = db[11];
	if (len >= 12)
		connector->audio_latency[1] = db[12];

	DRM_LOG_KMS("HDMI: DVI dual %d, "
@@ -1684,7 +1693,7 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
				break;
			case VENDOR_BLOCK:
				/* HDMI Vendor-Specific Data Block */
				if (db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
				if (dbl >= 5 && db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
					parse_hdmi_vsdb(connector, db);
				break;
			default: