linux-kernel - [PATCH 2/4] drm/edid: Ignore bad standard timings.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 23 Sep 2009 12:01:30 -0400
From:	Adam Jackson <ajax@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Adam Jackson <ajax@...hat.com>
Subject: [PATCH 2/4] drm/edid: Ignore bad standard timings.

Signed-off-by: Adam Jackson <ajax@...hat.com>
---
 drivers/gpu/drm/drm_edid.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3326987..dd35dc1 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -502,6 +502,19 @@ static struct drm_display_mode *drm_find_dmt(struct drm_device *dev,
 	}
 	return mode;
 }
+
+/*
+ * 0 is reserved.  The spec says 0x01 fill for unused timings.  Some old
+ * monitors fill with ascii space (0x20) instead.
+ */
+static int
+bad_std_timing(u8 a, u8 b)
+{
+	return (a == 0x00 && b == 0x00) ||
+	       (a == 0x01 && b == 0x01) ||
+	       (a == 0x20 && b == 0x20);
+}
+
 /**
  * drm_mode_std - convert standard mode info (width, height, refresh) into mode
  * @t: standard timing params
@@ -525,6 +538,9 @@ struct drm_display_mode *drm_mode_std(struct drm_device *dev,
 	unsigned vfreq = (t->vfreq_aspect & EDID_TIMING_VFREQ_MASK)
 		>> EDID_TIMING_VFREQ_SHIFT;
 
+	if (bad_std_timing(t->hsize, t->vfreq_aspect))
+		return NULL;
+
 	/* According to the EDID spec, the hdisplay = hsize * 8 + 248 */
 	hsize = t->hsize * 8 + 248;
 	/* vrefresh_rate = vfreq + 60 */
-- 
1.6.4.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/