[PATCH 6.4 034/800] md/raid10: fix overflow of md/safe_mode_delay

Greg Kroah-Hartman
2023-07-16T19:54:24Z

From: Li Nan <linan122@huawei.com>

[ Upstream commit 6beb489b2eed25978523f379a605073f99240c50 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 8e344b4b34446..b2d69260b5b1c 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;
--
2.39.2