Re: [RFC] netfilter: cttimeout: remove VLA in ctnl_timeout_parse_policy
From: Gustavo A. R. Silva
Date: Sun Mar 11 2018 - 18:45:54 EST
On 03/11/2018 05:21 PM, Pablo Neira Ayuso wrote:
On Sun, Mar 11, 2018 at 05:12:09PM -0500, Gustavo A. R. Silva wrote:
Hi Pablo,
On 03/11/2018 05:04 PM, Pablo Neira Ayuso wrote:
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?
We actually do have to initialized it because in the unlikely case that the
code block inside the 'if' below is not executed, then we will end up
freeing an uninitialized pointer.
I see, you're right indeed.
We can probably simplify this code, but just doing:
if (!l4proto->ctnl_timeout.nlattr_to_obj))
return 0;
I wonder if it is better to code this instead:
if (unlikely(!l4proto->ctnl_timeout.nlattr_to_obj)))
return 0;
netlink attribute parsing here.
You could even remove the likely() thing, which doesn't make much
sense for control plane code.
Why is that?
I understand this is a larger change, but I think this function will
look better while we're removing VLA.
Would you mind having a look? I'd appreciate if so.
I can do that. No problem.
Thanks
--
Gustavo