On Wed, Sep 15, 2021 at 09:47:25AM -0700, Andy Lutomirski wrote: > On Wed, Sep 15, 2021 at 8:50 AM Thomas Weißschuh <thomas@xxxxxxxx> wrote: > > > > Hi, > > > > I would like to propose a new syscall that exposes the functionality of > > request_module() to userspace. > > > > Propsed signature: request_module(char *module_name, char **args, int flags); > > Where args and flags have to be NULL and 0 for the time being. > > > > Rationale: > > > > We are using nested, privileged containers which are loading kernel modules. > > Currently we have to always pass around the contents of /lib/modules from the > > root namespace which contains the modules. > > (Also the containers need to have userspace components for moduleloading > > installed) > > > > The syscall would remove the need for this bookkeeping work. > > I feel like I'm missing something, and I don't understand the purpose > of this syscall. Wouldn't the right solution be for the container to > have a stub module loader (maybe doable with a special /sbin/modprobe > or maybe a kernel patch would be needed, depending on the exact use > case) and have the stub call out to the container manager to request > the module? The container manager would check its security policy and > load the module or not load it as appropriate. I don't see the need for a syscall like this yet either. This should be the job of the container manager. modprobe just calls the init_module() syscall, right? If so the seccomp notifier can be used to intercept this system call for the container and verify the module against an allowlist similar to how we currently handle mount. Christian
