Re: [PATCH xtables-addons 2/2] xt_DHCPMAC: replaced skb_make_writable with skb_ensure_writable.

[Florian Westphal <fw@xxxxxxxxx>]

Jeremy Sowden <jeremy@xxxxxxxxxx> wrote:
> skb_make_writable was removed from the kernel in 5.2 and its callers
> converted to use skb_ensure_writable.
> 
> Signed-off-by: Jeremy Sowden <jeremy@xxxxxxxxxx>
> ---
>  extensions/xt_DHCPMAC.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/extensions/xt_DHCPMAC.c b/extensions/xt_DHCPMAC.c
> index 47f9534f74c7..412f8984d326 100644
> --- a/extensions/xt_DHCPMAC.c
> +++ b/extensions/xt_DHCPMAC.c
> @@ -96,7 +96,7 @@ dhcpmac_tg(struct sk_buff *skb, const struct xt_action_param *par)
>  	struct udphdr udpbuf, *udph;
>  	unsigned int i;
>  
> -	if (!skb_make_writable(skb, 0))
> +	if (!skb_ensure_writable(skb, 0))
>  		return NF_DROP;

You need to drop the "!".  The "0" argument is suspicious as well, i
guess this needs to be "skb->len".