md/raid10: fix overflow of md/safe_mode_delay

[ Upstream commit 6beb489 ]

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: 72e0207 ("md: factor out parsing of fixed-point numbers")
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230522072535.1523740-2-linan666@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/md/md.c

@@ -3830,8 +3830,9 @@ 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)
@@ -3843,7 +3844,7 @@ 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;