[PATCH v2] md: raid1: fix potential OOB in raid1_remove_disk()

From: Zhang Shurong <zhang_shurong@foxmail.com>
To: song@kernel.org, yukuai1@huaweicloud.com
Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
	yukuai3@huawei.com, Zhang Shurong <zhang_shurong@foxmail.com>
Subject: [PATCH v2] md: raid1: fix potential OOB in raid1_remove_disk()
Date: Sat, 22 Jul 2023 15:53:53 +0800	[thread overview]
Message-ID: <tencent_0D24426FAC6A21B69AC0C03CE4143A508F09@qq.com> (raw)

If rddev->raid_disk is greater than mddev->raid_disks, there will be
an out-of-bounds in raid1_remove_disk(). We have already found
similar reports as follows:

1) commit d17f744e883b ("md-raid10: fix KASAN warning")
2) commit 1ebc2cec0b7d ("dm raid: fix KASAN warning in raid5_remove_disk")

Fix this bug by checking whether the "number" variable is
valid.

Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
Changes in v2:
 - Using conf->raid_disks instead of mddev->raid_disks.

 drivers/md/raid1.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index dd25832eb045..80aeee63dfb7 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1829,6 +1829,10 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
 	struct r1conf *conf = mddev->private;
 	int err = 0;
 	int number = rdev->raid_disk;
+
+	if (unlikely(number >= conf->raid_disks))
+		goto abort;
+
 	struct raid1_info *p = conf->mirrors + number;
 
 	if (rdev != p->rdev)
-- 
2.41.0

