| Message ID | 20190208005608.GA16399@embeddedor |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] netfilter: xt_recent: Use struct_size() in kvzalloc() | expand |
On Thu, Feb 07, 2019 at 06:56:08PM -0600, Gustavo A. R. Silva wrote: > 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. Applied, thanks.
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;
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@embeddedor.com> --- net/netfilter/xt_recent.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)