md/raid10: fix overflow of md/safe_mode_delay

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@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230522072535.1523740-2-linan666@huaweicloud.com

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 36af585b0e96aaedf0cedbbc389dabae0cc4e421..2fc8d25f6e8097c189f4aca76aa7ee0801e2cf6c 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3784,8 +3784,9 @@ 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)
@@ -3797,7 +3798,7 @@ 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;