[PATCH 6.6 091/192] ptp: fix integer overflow in max_vclocks_store

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@linaro.org>

[ Upstream commit 81d23d2a24012e448f651e007fac2cfd20a45ce0 ]

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@linaro.org>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>
Link: https://lore.kernel.org/r/ee8110ed-6619-4bd7-9024-28c1f2ac24f4@moroto.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 34ea5c16123a1..aefc06ae5d099 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -294,8 +294,7 @@ 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