On Thu, Aug 26, 2021 at 1:59 AM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > > On Thu, Aug 26, 2021 at 3:28 AM Peter Collingbourne <pcc@xxxxxxxxxx> wrote: > > > - } else { > > + } else if (is_dev_ioctl_cmd(cmd)) { > > struct ifreq ifr; > > bool need_copyout; > > if (copy_from_user(&ifr, argp, sizeof(struct ifreq))) > > @@ -1118,6 +1118,8 @@ static long sock_do_ioctl(struct net *net, struct socket *sock, > > if (!err && need_copyout) > > if (copy_to_user(argp, &ifr, sizeof(struct ifreq))) > > return -EFAULT; > > + } else { > > + err = -ENOTTY; > > } > > return err; > > } > > @@ -3306,6 +3308,8 @@ static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd, > > struct ifreq ifreq; > > u32 data32; > > > > + if (!is_dev_ioctl_cmd(cmd)) > > + return -ENOTTY; > > if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ)) > > return -EFAULT; > > if (get_user(data32, &u_ifreq32->ifr_data)) > > This adds yet another long switch() statement into the socket ioctl > case, when there > is already one in compat_sock_ioctl_trans(), one in dev_ifsioc() and one in > dev_ioctl(), all with roughly the same set of ioctl command codes. If I think that David's suggestion of using _IOC_TYPE() should be enough to address this for now. > any of them > are called frequently, that makes it all even slower, so I wonder if > there should > be a larger rework altogether. Maybe something based on a single lookup table > that we search through directly from sock_ioctl()/compat_sock_ioctl() to deal > with the differences in handling (ifreq based, compat handler, proto_ops > override, dev_load, rtnl_lock, rcu_read_lock, CAP_NET_ADMIN, copyout, ...). > > You are also adding the checks into different places for native and compat > mode, which makes them diverge more when we should be trying to > make them more common. > > I think based on my recent changes, some other simplifications are possible, > based on how the compat path already enumerates all the dev ioctls. I think we should leave that for a followup if still necessary. Peter