Re: [PATCH] nfc: netlink: avoid NULL pointer dereference on error

[Samuel Ortiz]

Hi Vincent,

On Wed, Oct 07, 2015 at 11:33:19AM +0200, Vincent Stehlé wrote:
> The function nfc_genl_llc_sdreq() can dereference the dev pointer while
> it is NULL on its error path. Create a new error handling label to avoid
> that.
> 
> This fixes the following coccinelle error:
> 
>   ./net/nfc/netlink.c:1175:21-24: ERROR: dev is NULL but dereferenced.
> 
> Signed-off-by: Vincent Stehlé <vincent.stehle@xxxxxxxxxxx>
> Cc: Thierry Escande <thierry.escande@xxxxxxxxxxxxxxx>
> Cc: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
> ---
>  net/nfc/netlink.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
> index 853172c..51c48f0 100644
> --- a/net/nfc/netlink.c
> +++ b/net/nfc/netlink.c
> @@ -1111,7 +1111,7 @@ static int nfc_genl_llc_sdreq(struct sk_buff *skb, struct genl_info *info)
>  	dev = nfc_get_device(idx);
>  	if (!dev) {
>  		rc = -ENODEV;
> -		goto exit;
> +		goto exit_nodev;
>  	}
Julia Lawall sent a better fix that I applied:

-       if (!dev) {
-               rc = -ENODEV;
-               goto exit;
-       }
+       if (!dev)
+               return -ENODEV;

Cheers,
Samuel.
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