[PATCH] Bluetooth: Fix incorrect strncpy() in hidp_setup_hid()

[Luis Henriques]

Hit 'send' too soon... Forgot to specify this is for the Lucid kernel,
to fix CVE-2013-0349.

On Tue, Apr 09, 2013 at 11:52:31AM +0100, Luis Henriques wrote:
> From: Anderson Lizardo <anderson.lizardo at openbossa.org>
> 
> CVE-2013-0349
> 
> BugLink: http://bugs.launchpad.net/bugs/1134503
> 
> The length parameter should be sizeof(req->name) - 1 because there is no
> guarantee that string provided by userspace will contain the trailing
> '\0'.
> 
> Can be easily reproduced by manually setting req->name to 128 non-zero
> bytes prior to ioctl(HIDPCONNADD) and checking the device name setup on
> input subsystem:
> 
> $ cat /sys/devices/pnp0/00\:04/tty/ttyS0/hci0/hci0\:1/input8/name
> AAAAAA[...]AAAAAAAAf0:af:f0:af:f0:af
> 
> ("f0:af:f0:af:f0:af" is the device bluetooth address, taken from "phys"
> field in struct hid_device due to overflow.)
> 
> Cc: stable at vger.kernel.org
> Signed-off-by: Anderson Lizardo <anderson.lizardo at openbossa.org>
> Acked-by: Marcel Holtmann <marcel at holtmann.org>
> Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> (back ported from commit 0a9ab9bdb3e891762553f667066190c1d22ad62b)
> 
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
>  net/bluetooth/hidp/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
> index 49d8495..0c2c59d 100644
> --- a/net/bluetooth/hidp/core.c
> +++ b/net/bluetooth/hidp/core.c
> @@ -778,7 +778,7 @@ static int hidp_setup_hid(struct hidp_session *session,
>  	hid->version = req->version;
>  	hid->country = req->country;
>  
> -	strncpy(hid->name, req->name, 128);
> +	strncpy(hid->name, req->name, sizeof(req->name) - 1);
>  	strncpy(hid->phys, batostr(&src), 64);
>  	strncpy(hid->uniq, batostr(&dst), 64);
>  
> -- 
> 1.8.1.2
> 
> 
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Cheers,
--
Luis