2019-05-01 22:02:59

by Gustavo A. R. Silva

Subject: [PATCH][next] netfilter: xt_hashlimit: use struct_size() helper

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace code of the following form:

sizeof(struct xt_hashlimit_htable) + sizeof(struct hlist_head) * size

with:

struct_size(hinfo, hash, size)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
net/netfilter/xt_hashlimit.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 8d86e39d6280..a30536b17ee1 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -288,8 +288,7 @@ static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg,
size = 16;
}
/* FIXME: don't use vmalloc() here or anywhere else -HW */
- hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
- sizeof(struct hlist_head) * size);
+ hinfo = vmalloc(struct_size(hinfo, hash, size));
if (hinfo == NULL)
return -ENOMEM;
*out_hinfo = hinfo;
--
2.21.0

2019-05-05 23:05:39

by Pablo Neira Ayuso

Subject: Re: [PATCH][next] netfilter: xt_hashlimit: use struct_size() helper

On Wed, May 01, 2019 at 05:01:08PM -0500, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
>
> So, replace code of the following form:
>
> sizeof(struct xt_hashlimit_htable) + sizeof(struct hlist_head) * size
>
> with:
>
> struct_size(hinfo, hash, size)
>
> This code was detected with the help of Coccinelle.

Applied, thanks.