misc: c2port: core: Make copying name from userspace more secure

Currently the 'c2dev' device data is not initialised when it's
allocated.  There maybe an issue when using strncpy() to populate the
'name' attribute since a NUL terminator may not be provided in all
use-cases.  To prevent such a failing, let's ensure the 'c2dev'
device data area is fully zeroed out on allocation.

Cc: Rodolfo Giometti <giometti@enneenne.com>
Cc: "Eurotech S.p.A" <info@eurotech.it>
Cc: David Laight <David.Laight@aculab.com>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201102142001.560490-1-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/c2port/core.c b/drivers/misc/c2port/core.c
index 80d87e8a0bea980aeafa111f98cf4968a6f4551d..fb9a1b49ff6de77a911d90c40f57a498fa49cd60 100644 (file)
--- a/drivers/misc/c2port/core.c
+++ b/drivers/misc/c2port/core.c
@@ -899,7 +899,7 @@ struct c2port_device *c2port_device_register(char *name,
                unlikely(!ops->c2d_get) || unlikely(!ops->c2d_set))
                return ERR_PTR(-EINVAL);
 
-       c2dev = kmalloc(sizeof(struct c2port_device), GFP_KERNEL);
+       c2dev = kzalloc(sizeof(struct c2port_device), GFP_KERNEL);
        if (unlikely(!c2dev))
                return ERR_PTR(-ENOMEM);