[PATCH 01/10] misc: c2port: core: Ensure source size does not equal destination size in strncpy()

From: Lee Jones <lee.jones@linaro.org>
To: arnd@arndb.de, gregkh@linuxfoundation.org
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
	Rodolfo Giometti <giometti@linux.it>,
	"Eurotech S.p.A" <info@eurotech.it>
Subject: [PATCH 01/10] misc: c2port: core: Ensure source size does not equal destination size in strncpy()
Date: Fri, 26 Jun 2020 14:05:16 +0100	[thread overview]
Message-ID: <20200626130525.389469-2-lee.jones@linaro.org> (raw)
In-Reply-To: <20200626130525.389469-1-lee.jones@linaro.org>

We need to ensure there's a place for the NULL terminator.

Fixes the following W=1 warning(s):

 In file included from include/linux/bitmap.h:9,
 from include/linux/nodemask.h:95,
 from include/linux/mmzone.h:17,
 from include/linux/gfp.h:6,
 from include/linux/umh.h:4,
 from include/linux/kmod.h:9,
 from include/linux/module.h:16,
 from drivers/misc/c2port/core.c:9:
 In function ‘strncpy’,
 inlined from ‘c2port_device_register’ at drivers/misc/c2port/core.c:926:2:
 include/linux/string.h:297:30: warning: ‘__builtin_strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
 297 | #define __underlying_strncpy __builtin_strncpy
 | ^
 include/linux/string.h:307:9: note: in expansion of macro ‘__underlying_strncpy’
 307 | return __underlying_strncpy(p, q, size);
 | ^~~~~~~~~~~~~~~~~~~~

Cc: Rodolfo Giometti <giometti@linux.it>
Cc: "Eurotech S.p.A" <info@eurotech.it>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/misc/c2port/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/c2port/core.c b/drivers/misc/c2port/core.c
index 33bba18022892..80d87e8a0bea9 100644
--- a/drivers/misc/c2port/core.c
+++ b/drivers/misc/c2port/core.c
@@ -923,7 +923,7 @@ struct c2port_device *c2port_device_register(char *name,
 	}
 	dev_set_drvdata(c2dev->dev, c2dev);
 
-	strncpy(c2dev->name, name, C2PORT_NAME_LEN);
+	strncpy(c2dev->name, name, C2PORT_NAME_LEN - 1);
 	c2dev->ops = ops;
 	mutex_init(&c2dev->mutex);
 
-- 
2.25.1

