On Tue, Feb 4, 2025 at 2:51 PM Christian Brauner <brauner@xxxxxxxxxx> wrote: > Pidfs supports extensible and non-extensible ioctls. The extensible > ioctls need to check for the ioctl number itself not just the ioctl > command otherwise both backward- and forward compatibility are broken. > > The pidfs ioctl handler also needs to look at the type of the ioctl > command to guard against cases where "[...] a daemon receives some > random file descriptor from a (potentially less privileged) client and > expects the FD to be of some specific type, it might call ioctl() on > this FD with some type-specific command and expect the call to fail if > the FD is of the wrong type; but due to the missing type check, the > kernel instead performs some action that userspace didn't expect." > (cf. [1]] Thanks, this looks good to me.
