From patchwork Fri Mar 13 16:20:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= X-Patchwork-Id: 11437383 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E79131667 for ; Fri, 13 Mar 2020 16:21:23 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D04322072C for ; Fri, 13 Mar 2020 16:21:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D04322072C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9BD916EC17; Fri, 13 Mar 2020 16:21:21 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8B2E46EC17; Fri, 13 Mar 2020 16:21:18 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Mar 2020 09:21:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,549,1574150400"; d="scan'208";a="354399442" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by fmsmga001.fm.intel.com with SMTP; 13 Mar 2020 09:21:15 -0700 Received: by stinkbox (sSMTP sendmail emulation); Fri, 13 Mar 2020 18:21:14 +0200 From: Ville Syrjala To: dri-devel@lists.freedesktop.org Subject: [PATCH 6/9] drm/edid: Don't parse garbage as DispID blocks Date: Fri, 13 Mar 2020 18:20:51 +0200 Message-Id: <20200313162054.16009-7-ville.syrjala@linux.intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200313162054.16009-1-ville.syrjala@linux.intel.com> References: <20200313162054.16009-1-ville.syrjala@linux.intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Ville Syrjälä Currently the code assumes that the entire EDID extesion block can be taken up by the DispID blocks. That is not true. There is at least always the DispID checksum, and potentially fill bytes if the extension block uses the interior fill scheme to pad out to fill EDID block size. So let's not parse the checksum or the fill bytes as DispID blocks by having drm_find_displayid_extension() return the actual length of the DispID data to the caller. Signed-off-by: Ville Syrjälä --- drivers/gpu/drm/drm_edid.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index dbd2e8474c2a..3067be710e5b 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -3216,6 +3216,7 @@ static u8 *drm_find_displayid_extension(const struct edid *edid, int *length, int *idx) { u8 *displayid = drm_find_edid_extension(edid, DISPLAYID_EXT); + struct displayid_hdr *base; int ret; if (!displayid) @@ -3228,6 +3229,9 @@ static u8 *drm_find_displayid_extension(const struct edid *edid, if (ret) return NULL; + base = (struct displayid_hdr *)&displayid[*idx]; + *length = *idx + sizeof(*base) + base->bytes; + return displayid; }