From: Yangbo Lu <yangbo.lu@nxp.com>
To: <linux-mmc@vger.kernel.org>, <ulf.hansson@linaro.org>,
        Scott Wood <oss@buserror.net>, Arnd Bergmann <arnd@arndb.de>
CC: <linuxppc-dev@lists.ozlabs.org>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <linux-clk@vger.kernel.org>, <linux-i2c@vger.kernel.org>,
        <iommu@lists.linux-foundation.org>, <netdev@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mark Rutland <mark.rutland@arm.com>, Rob Herring <robh+dt@kernel.org>,
        Russell King <linux@arm.linux.org.uk>,
        Jochen Friedrich <jochen@scram.de>, Joerg Roedel <joro@8bytes.org>,
        Claudiu Manoil <claudiu.manoil@freescale.com>,
        Bhupesh Sharma <bhupesh.sharma@freescale.com>,
        Qiang Zhao <qiang.zhao@nxp.com>, Kumar Gala <galak@codeaurora.org>,
        Leo Li <leoyang.li@nxp.com>, Xiaobo Xie <xiaobo.xie@nxp.com>,
        Minghuan Lian <minghuan.lian@nxp.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [v16, 6/7] base: soc: Check for NULL SoC device attributes
Date: Wed, 9 Nov 2016 11:14:11 +0800
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From: Geert Uytterhoeven <geert+renesas@glider.be>

If soc_device_match() is used to check the value of a specific
attribute that is not present for the current SoC, the kernel crashes
with a NULL pointer dereference.

Fix this by explicitly checking for the absence of a needed property,
and considering this a non-match.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
Changes for v16:
	- Added this patch
---
 drivers/base/soc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/base/soc.c b/drivers/base/soc.c
index 0c5cf87..0e701e2 100644
--- a/drivers/base/soc.c
+++ b/drivers/base/soc.c
@@ -167,19 +167,23 @@ static int soc_device_match_one(struct device *dev, void *arg)
 	const struct soc_device_attribute *match = arg;
 
 	if (match->machine &&
-	    !glob_match(match->machine, soc_dev->attr->machine))
+	    (!soc_dev->attr->machine ||
+	     !glob_match(match->machine, soc_dev->attr->machine)))
 		return 0;
 
 	if (match->family &&
-	    !glob_match(match->family, soc_dev->attr->family))
+	    (!soc_dev->attr->family ||
+	     !glob_match(match->family, soc_dev->attr->family)))
 		return 0;
 
 	if (match->revision &&
-	    !glob_match(match->revision, soc_dev->attr->revision))
+	    (!soc_dev->attr->revision ||
+	     !glob_match(match->revision, soc_dev->attr->revision)))
 		return 0;
 
 	if (match->soc_id &&
-	    !glob_match(match->soc_id, soc_dev->attr->soc_id))
+	    (!soc_dev->attr->soc_id ||
+	     !glob_match(match->soc_id, soc_dev->attr->soc_id)))
 		return 0;
 
 	return 1;
-- 
2.1.0.27.g96db324