From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
size = sizeof(struct foo) + count * sizeof(void *);
instance = alloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
size = struct_size(instance, entry, count);
instance = alloc(size, GFP_KERNEL)
Notice that, in this case, variable sz is not necessary, hence it is
removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/xt_recent.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index f44de4bc2100..1664d2ec8b2f 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -337,7 +337,6 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
unsigned int nstamp_mask;
unsigned int i;
int ret = -EINVAL;
- size_t sz;
net_get_random_once(&hash_rnd, sizeof(hash_rnd));
@@ -387,8 +386,7 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
goto out;
}
- sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
- t = kvzalloc(sz, GFP_KERNEL);
+ t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL);
if (t == NULL) {
ret = -ENOMEM;
goto out;
--
2.11.0
