[PATCH] ptp: add range check on n_samples

[Dong Zhu <bluezhudong@gmail.com>]

>From d4eb97e8d5def76d46167c91059147e2c7d33433 Mon Sep 17 00:00:00 2001

When using PTP_SYS_OFFSET ioctl to measure the time offset between the
PHC and system clock, we need to specify the number of measurements, the
valid value of n_samples is between 1 to 25. If n_samples <= 0 or > 25
it makes no sense, so this patch intends to add a range check.

Signed-off-by: Dong Zhu <bluezhudong@gmail.com>
---
 drivers/ptp/ptp_chardev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 34a0c60..4e85b23 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -104,7 +104,8 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
 			err = -EFAULT;
 			break;
 		}
-		if (sysoff->n_samples > PTP_MAX_SAMPLES) {
+		if (sysoff->n_samples <= 0 ||
+		    sysoff->n_samples > PTP_MAX_SAMPLES) {
 			err = -EINVAL;
 			break;
 		}
-- 
1.7.11.7

-- 
Best Regards,
Dong Zhu