[4.2.y-ckt stable] Patch "drm/i915/dsi: defend gpio table against out of bounds access" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drm/i915/dsi: defend gpio table against out of bounds access

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt5.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From b407c7ae40cdfae349c20359bf298f3b74213c94 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula at intel.com>
Date: Thu, 4 Feb 2016 12:50:49 +0200
Subject: drm/i915/dsi: defend gpio table against out of bounds access
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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commit 4db3a2448ec8902310acb78de39b6227a9a56ac8 upstream.

Do not blindly trust the VBT data used for indexing.

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/cc32d40c2b47f2d2151811855ac2c3dabab1d57d.1454582914.git.jani.nikula@intel.com
(cherry picked from commit 5d2d0a12d3d08bf50434f0b5947bb73bac04b941)
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
index a5e99ac..349775e 100644
--- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
@@ -209,6 +209,11 @@ static const u8 *mipi_exec_gpio(struct intel_dsi *intel_dsi, const u8 *data)
 	/* pull up/down */
 	action = *data++;

+	if (gpio >= ARRAY_SIZE(gtable)) {
+		DRM_DEBUG_KMS("unknown gpio %u\n", gpio);
+		goto out;
+	}
+
 	function = gtable[gpio].function_reg;
 	pad = gtable[gpio].pad_reg;

@@ -226,6 +231,7 @@ static const u8 *mipi_exec_gpio(struct intel_dsi *intel_dsi, const u8 *data)
 	vlv_gpio_nc_write(dev_priv, pad, val);
 	mutex_unlock(&dev_priv->sb_lock);

+out:
 	return data;
 }

--
2.7.0