linux-kernel - [RFC] netfilter: cttimeout: remove VLA in ctnl_timeout_parse

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Date:   Tue, 6 Mar 2018 12:47:55 -0600
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>
Cc:     netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [RFC] netfilter: cttimeout: remove VLA in ctnl_timeout_parse_policy

In preparation to enabling -Wvla, remove VLA and replace it
with dynamic memory allocation.

Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
---
 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;
 
 	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