From: Arnd Bergmann <arnd@arndb.de>
To: linux-kernel@vger.kernel.org, Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Guenter Roeck <linux@roeck-us.net>, akpm@linux-foundation.org,
        netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
        "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, x86@kernel.org,
        Arnd Bergmann <arnd@arndb.de>,
        Mario Limonciello <mario.limonciello@dell.com>,
        Arvind Yadav <arvind.yadav.cs@gmail.com>,
        platform-driver-x86@vger.kernel.org
Subject: [PATCH 17/22] platform/x86: alienware-wmi: fix format string overflow warning
Date: Fri, 14 Jul 2017 14:07:09 +0200
Message-Id: <20170714120720.906842-18-arnd@arndb.de>
In-Reply-To: <20170714120720.906842-1-arnd@arndb.de>
References: <20170714120720.906842-1-arnd@arndb.de>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1386
Lines: 34

gcc points out a possible format string overflow for a large value of 'zone':

drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init':
drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=]
   sprintf(buffer, "zone%02X", i);
                        ^~~~
drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646]
   sprintf(buffer, "zone%02X", i);
                   ^~~~~~~~~~
drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10

While the zone should never be that large, it's easy to make the
buffer a few bytes longer so gcc can prove this to be safe.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/platform/x86/alienware-wmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c
index 0831b428c217..acc01242da82 100644
--- a/drivers/platform/x86/alienware-wmi.c
+++ b/drivers/platform/x86/alienware-wmi.c
@@ -421,7 +421,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, show_control_state,
 static int alienware_zone_init(struct platform_device *dev)
 {
 	int i;
-	char buffer[10];
+	char buffer[13];
 	char *name;
 
 	if (interface == WMAX) {
-- 
2.9.0