md: raid1: fix potential OOB in raid1_remove_disk()

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>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/tencent_0D24426FAC6A21B69AC0C03CE4143A508F09@qq.com
Signed-off-by: Song Liu <song@kernel.org>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 23d2119..b920f92 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1837,6 +1837,10 @@ 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)