ptp: use memdup_user().

Use memdup_user to duplicate a memory region from user-space to
kernel-space, instead of open coding using kmalloc & copy_from_user.

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Muhammad Falak R Wani 2016-05-20 17:51:02 +05:30 committed by David S. Miller
parent 8da07a393f
commit 2ece068e1b

View File

@ -208,14 +208,9 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
break;
case PTP_SYS_OFFSET:
sysoff = kmalloc(sizeof(*sysoff), GFP_KERNEL);
if (!sysoff) {
err = -ENOMEM;
break;
}
if (copy_from_user(sysoff, (void __user *)arg,
sizeof(*sysoff))) {
err = -EFAULT;
sysoff = memdup_user((void __user *)arg, sizeof(*sysoff));
if (IS_ERR(sysoff)) {
err = PTR_ERR(sysoff);
break;
}
if (sysoff->n_samples > PTP_MAX_SAMPLES) {