On Tue, Jul 12, 2022 at 10:22 AM Peter Xu <peterx@xxxxxxxxxx> wrote: > On Fri, Jul 08, 2022 at 11:34:51AM +0200, Ondrej Mosnacek wrote: > > Since userfaultfd doesn't implement a write operation, it is more > > appropriate to open it read-only. > > > > When userfaultfds are opened read-write like it is now, and such fd is > > passed from one process to another, SELinux will check both read and > > write permissions for the target process, even though it can't actually > > do any write operation on the fd later. > > > > Inspired by the following bug report, which has hit the SELinux scenario > > described above: > > https://bugzilla.redhat.com/show_bug.cgi?id=1974559 > > > > Reported-by: Robert O'Callahan <roc@xxxxxxxxxxxxx> > > Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") > > Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx> > > Acked-by: Peter Xu <peterx@xxxxxxxxxx> Thanks Peter. -- paul-moore.com
