[PATCH v2 net] ptp: fix integer overflow in max_vclocks_store

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

On 32bit systems, the "4 * max" multiply can overflow.  Use kcalloc()
to do the allocation to prevent this.

Fixes: 44c494c8e30e ("ptp: track available ptp vclocks information")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
v2: It's better to use kcalloc() instead of size_mul().

 drivers/ptp/ptp_sysfs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index a15460aaa03b..6b1b8f57cd95 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -296,8 +296,7 @@ static ssize_t max_vclocks_store(struct device *dev,
 	if (max < ptp->n_vclocks)
 		goto out;
 
-	size = sizeof(int) * max;
-	vclock_index = kzalloc(size, GFP_KERNEL);
+	vclock_index = kcalloc(max, sizeof(int), GFP_KERNEL);
 	if (!vclock_index) {
 		err = -ENOMEM;
 		goto out;
-- 
2.43.0