Re: [PATCH] md: fix potential OOB in multipath_remove_disk()

[Paul Menzel]

Dear Song, Zhang and Christoph,


Am 29.07.23 um 12:46 schrieb Song Liu:
> On Sat, Jul 15, 2023 at 5:45 PM Zhang Shurong wrote:
> > 在 2023年7月13日星期四 CST 上午12:50:19，Christoph Hellwig 写道：
> > > On Thu, Jul 13, 2023 at 12:46:05AM +0800, Zhang Shurong wrote:
> > > > If rddev->raid_disk is greater than mddev->raid_disks, there will be
> > > > an out-of-bounds in multipath_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.
> > >
> > > I think it might just be time to finally dropped the deprecated md
> > > multipath code instead..
> > Should I write another patch to delete them?
>
> Yes, please write a patch to delete the multipath code.

How would fixing this bug work with the stable series? Probably a 
removal patch wouldn’t be picked, right? Shouldn’t the fix be accepted 
in master, and then the code be removed?


Kind regards,

Paul