On Tue, Mar 03, 2020 at 12:33:48PM +0100, Miklos Szeredi wrote: > On Tue, Mar 3, 2020 at 11:25 AM Christian Brauner > <christian.brauner@xxxxxxxxxx> wrote: > > > > On Tue, Mar 03, 2020 at 11:13:50AM +0100, Miklos Szeredi wrote: > > > On Tue, Mar 3, 2020 at 11:00 AM Christian Brauner > > > <christian.brauner@xxxxxxxxxx> wrote: > > > > > More magic links to beam you around sounds like a bad idea. We had a > > > > bunch of CVEs around them in containers and they were one of the major > > > > reasons behind us pushing for openat2(). That's why it has a > > > > RESOLVE_NO_MAGICLINKS flag. > > > > > > No, that link wouldn't beam you around at all, it would end up in an > > > internally mounted instance of a mountfs, a safe place where no > > > > Even if it is a magic link to a safe place it's a magic link. They > > aren't a great solution to this problem. fsinfo() is cleaner and > > simpler as it creates a context for a supervised mount which gives the a > > managing application fine-grained control and makes it easily > > extendable. > > Yeah, it's a nice and clean interface in the ioctl(2) sense. Sure, > fsinfo() is way better than ioctl(), but it at the core it's still the > same syscall multiplexer, do everything hack. In contrast to a generic ioctl() it's a domain-specific separate syscall. You can't suddenly set kvm options through fsinfo() I would hope. I find it at least debatable that a new filesystem is preferable. And - feel free to simply dismiss the concerns I expressed - so far there has not been a lot of excitement about this idea. > > > Also, we're apparently at the point where it seems were suggesting > > another (pseudo)filesystem to get information about filesystems. > > Implementation detail. Why would you care? I wouldn't call this an implementation detail. That's quite a big design choice; it's a separate fileystem. In addition, implementation details need to be maintained. Christian
