Re: [RFC] netfilter: cttimeout: remove VLA in ctnl_timeout_parse_policy

From: Pablo Neira Ayuso
Date: Sun Mar 11 2018 - 18:04:24 EST


On Tue, Mar 06, 2018 at 12:47:55PM -0600, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wvla, remove VLA and replace it
> with dynamic memory allocation.

Looks good but...

> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
> net/netfilter/nfnetlink_cttimeout.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c
> index 95b0470..a2f7d92 100644
> --- a/net/netfilter/nfnetlink_cttimeout.c
> +++ b/net/netfilter/nfnetlink_cttimeout.c
> @@ -52,18 +52,26 @@ ctnl_timeout_parse_policy(void *timeouts,
> struct net *net, const struct nlattr *attr)
> {
> int ret = 0;
> + struct nlattr **tb = NULL;

I think we don't need to initialize this, right?

>
> if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
> - struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
> + tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb),
> + GFP_KERNEL);
> +
> + if (!tb)
> + return -ENOMEM;
>
> ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
> attr, l4proto->ctnl_timeout.nla_policy,
> NULL);
> if (ret < 0)
> - return ret;
> + goto err;
>
> ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts);
> }
> +
> +err:
> + kfree(tb);
> return ret;
> }
>
> --
> 2.7.4
>