Hi, On Mon, Oct 3, 2022 at 12:01 PM Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > > On Mon, Oct 03, 2022 at 08:33:13AM +0100, Fuad Tabba wrote: > > > I think it is "don't do that" category. inaccessible_register_notifier() > > > caller has to know what file it operates on, no? > > > > The thing is, you could oops the kernel from userspace. For that, all > > you have to do is a memfd_create without the MFD_INACCESSIBLE, > > followed by a KVM_SET_USER_MEMORY_REGION using that as the private_fd. > > I ran into this using my port of this patch series to arm64. > > My point is that it has to be handled on a different level. KVM has to > reject private_fd if it is now inaccessible. It should be trivial by > checking file->f_inode->i_sb->s_magic. Yes, that makes sense. Thanks, /fuad > -- > Kiryl Shutsemau / Kirill A. Shutemov
