On Mon, Jul 21, 2014 at 2:47 PM, Seth Forshee <seth.fors...@canonical.com> wrote: > On Fri, Jul 18, 2014 at 05:33:23PM +0200, Miklos Szeredi wrote: >> On Mon, Jul 14, 2014 at 9:18 PM, Seth Forshee >> <seth.fors...@canonical.com> wrote: >> > Update fuse to allow mounts from user namespaces. During mount >> > current_user_ns() is stashed away, >> >> Same thing here. While practically this may work, it's theoretically >> wrong, and possibly may go wrong in special situations. In fuse >> there's no official "server process", so storing information, like >> namespace, about one is going to be wrong. > > What you're suggesting would probably work fine when dealing with pids. > It's not going to work though for the checks I've added in > fuse_allow_current_process() that the process is in the mount owner's > user ns, and without those checks or something similar I don't think > it's safe to permit allow_other for user ns mounts.
You can add that check in fuse_dev_do_read() as well. If the fsuid/fsgid doesn't exist in the "server's" namespace, then set req->out.h.error and call request_end(). > Can you elaborate on what special situations might violate these > assumptions or otherwise cause problems? What's preventing a fuse fs implementation from handling FUSE_INIT in one process and then handling the rest in a different process (possibly in a different namespace)? Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
