[PATCH][net-next] netfilter: ebtables: use array_size() helper in copy_{from,to}_user()

Gustavo A. R. Silva
2021-09-28T20:02:48Z

Use array_size() helper instead of the open-coded version in
copy_{from,to}_user(). These sorts of multiplication factors
need to be wrapped in array_size().

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
net/bridge/netfilter/ebtables.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 83d1798dfbb4..32fa05ec4a6d 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1071,7 +1071,7 @@ static int do_replace_finish(struct net *net, struct ebt_replace *repl,
*/
if (repl->num_counters &&
copy_to_user(repl->counters, counterstmp,
- repl->num_counters * sizeof(struct ebt_counter))) {
+ array_size(repl->num_counters, sizeof(struct ebt_counter)))) {
/* Silent error, can't fail, new table is already in place */
net_warn_ratelimited("ebtables: counters copy to user failed while replacing table\n");
}
@@ -1399,7 +1399,8 @@ static int do_update_counters(struct net *net, const char *name,
goto unlock_mutex;
}

- if (copy_from_user(tmp, counters, num_counters * sizeof(*counters))) {
+ if (copy_from_user(tmp, counters,
+ array_size(num_counters, sizeof(*counters)))) {
ret = -EFAULT;
goto unlock_mutex;
}
@@ -1532,7 +1533,7 @@ static int copy_counters_to_user(struct ebt_table *t,
write_unlock_bh(&t->lock);

if (copy_to_user(user, counterstmp,
- nentries * sizeof(struct ebt_counter)))
+ array_size(nentries, sizeof(struct ebt_counter))))
ret = -EFAULT;
vfree(counterstmp);
return ret;
--
2.27.0