Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <tencent_59C6505725F46EF26BE7B6E8C0363C2A1509@qq.com>
From:   Zhang Shurong <zhang_shurong@foxmail.com>
To:     song@kernel.org
Cc:     linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
        Zhang Shurong <zhang_shurong@foxmail.com>
Subject: [PATCH] md: raid1: fix potential OOB in raid1_remove_disk()
Date:   Sun, 16 Jul 2023 00:11:47 +0800
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index dd25832eb045..3e294dc408fa 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 >= mddev->raid_disks))
+		goto abort;
+
 	struct raid1_info *p = conf->mirrors + number;
 
 	if (rdev != p->rdev)
-- 
2.30.2