2023-07-15 16:41:55

by Zhang Shurong

Subject: [PATCH] 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 <[email protected]>
---
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

2023-07-17 01:14:53

by Yu Kuai

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

Hi,

?? 2023/07/16 0:11, Zhang Shurong д??:
> 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 <[email protected]>
> ---
> 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;
> +
This looks correct, but I prefer to use conf->raid_disks directly.

Thanks,
Kuai

> struct raid1_info *p = conf->mirrors + number;
>
> if (rdev != p->rdev)
>