[PATCH v4 1/3] md/raid10: fix overflow of md/safe_mode_delay

[linan666]

From: Li Nan <linan122@xxxxxxxxxx>

There is no input check when echo md/safe_mode_delay in safe_delay_store().
And msec might also overflow when HZ < 1000 in safe_delay_show(), Fix it by
checking overflow in safe_delay_store() and use unsigned long conversion in
safe_delay_show().

Fixes: 72e02075a33f ("md: factor out parsing of fixed-point numbers")
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
 drivers/md/md.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8e344b4b3444..b2d69260b5b1 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3794,8 +3794,9 @@ int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
 static ssize_t
 safe_delay_show(struct mddev *mddev, char *page)
 {
-	int msec = (mddev->safemode_delay*1000)/HZ;
-	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
+	unsigned int msec = ((unsigned long)mddev->safemode_delay*1000)/HZ;
+
+	return sprintf(page, "%u.%03u\n", msec/1000, msec%1000);
 }
 static ssize_t
 safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
@@ -3807,7 +3808,7 @@ safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
 		return -EINVAL;
 	}
 
-	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
+	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0 || msec > UINT_MAX / HZ)
 		return -EINVAL;
 	if (msec == 0)
 		mddev->safemode_delay = 0;
-- 
2.31.1