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From:   Lee Jones <lee.jones@linaro.org>
To:     gregkh@linuxfoundation.org, arnd@arndb.de
Cc:     linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
        Rodolfo Giometti <giometti@enneenne.com>,
        "Eurotech S.p.A" <info@eurotech.it>,
        Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 1/2] misc: c2port: core: Make copying name from userspace more secure
Date:   Mon,  2 Nov 2020 11:12:10 +0000
Message-Id: <20201102111211.1047972-1-lee.jones@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

strncpy() may not provide a NUL terminator, which means that a 1-byte
leak would be possible *if* this was ever copied to userspace.  Ensure
the buffer will always be NUL terminated by using the kernel's
strscpy() which a) uses the destination (instead of the source) size
as the bytes to copy and b) is *always* NUL terminated.

Cc: Rodolfo Giometti <giometti@enneenne.com>
Cc: "Eurotech S.p.A" <info@eurotech.it>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
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 80d87e8a0bea9..b96444ec94c7e 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 - 1);
+	strscpy(c2dev->name, name, sizeof(c2dev->name));
 	c2dev->ops = ops;
 	mutex_init(&c2dev->mutex);
 
-- 
2.25.1