dev_ioctl: pass SIOCDEVPRIVATE data separately

The compat handlers for SIOCDEVPRIVATE are incorrect for any driver that
passes data as part of struct ifreq rather than as an ifr_data pointer, or
that passes data back this way, since the compat_ifr_data_ioctl() helper
overwrites the ifr_data pointer and does not copy anything back out.

Since all drivers using devprivate commands are now converted to the
new .ndo_siocdevprivate callback, fix this by adding the missing piece
and passing the pointer separately the whole way.

This further unifies the native and compat logic for socket ioctls,
as the new code now passes the correct pointer as well as the correct
data for both native and compat ioctls.

Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/netdevice.h

···
 int get_user_ifreq(struct ifreq *ifr, void __user **ifrdata, void __user *arg);
 int put_user_ifreq(struct ifreq *ifr, void __user *arg);
 int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr,
-		bool *need_copyout);
+		void __user *data, bool *need_copyout);
 int dev_ifconf(struct net *net, struct ifconf __user *ifc);
-int dev_ethtool(struct net *net, struct ifreq *);
+int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *userdata);
 unsigned int dev_get_flags(const struct net_device *);
 int __dev_change_flags(struct net_device *dev, unsigned int flags,
 		       struct netlink_ext_ack *extack);

net/core/dev_ioctl.c

···
 	return err;
 }
 
-static int dev_siocdevprivate(struct net_device *dev,
-			      struct ifreq *ifr, unsigned int cmd)
+static int dev_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
+			      void __user *data, unsigned int cmd)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
-	void __user *data = ifr->ifr_data;
 
 	if (ops->ndo_siocdevprivate) {
 		if (netif_device_present(dev))
···
 	}
 
 	/* fall back to do_ioctl for drivers not yet converted */
+	ifr->ifr_data = data;
 	return dev_do_ioctl(dev, ifr, cmd);
 }
 
 /*
  *	Perform the SIOCxIFxxx calls, inside rtnl_lock()
  */
-static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
+static int dev_ifsioc(struct net *net, struct ifreq *ifr, void __user *data,
+		      unsigned int cmd)
 {
 	int err;
 	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
···
 	default:
 		if (cmd >= SIOCDEVPRIVATE &&
 		    cmd <= SIOCDEVPRIVATE + 15)
-			return dev_siocdevprivate(dev, ifr, cmd);
+			return dev_siocdevprivate(dev, ifr, data, cmd);
 
 		if (cmd == SIOCBONDENSLAVE ||
 		    cmd == SIOCBONDRELEASE ||
···
  *	positive or a negative errno code on error.
  */
 
-int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_copyout)
+int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr,
+	      void __user *data, bool *need_copyout)
 {
 	int ret;
 	char *colon;
···
 	case SIOCETHTOOL:
 		dev_load(net, ifr->ifr_name);
 		rtnl_lock();
-		ret = dev_ethtool(net, ifr);
+		ret = dev_ethtool(net, ifr, data);
 		rtnl_unlock();
 		if (colon)
 			*colon = ':';
···
 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			return -EPERM;
 		rtnl_lock();
-		ret = dev_ifsioc(net, ifr, cmd);
+		ret = dev_ifsioc(net, ifr, data, cmd);
 		rtnl_unlock();
 		if (colon)
 			*colon = ':';
···
 	case SIOCBONDINFOQUERY:
 		dev_load(net, ifr->ifr_name);
 		rtnl_lock();
-		ret = dev_ifsioc(net, ifr, cmd);
+		ret = dev_ifsioc(net, ifr, data, cmd);
 		rtnl_unlock();
 		if (need_copyout)
 			*need_copyout = false;
···
 		     cmd <= SIOCDEVPRIVATE + 15)) {
 			dev_load(net, ifr->ifr_name);
 			rtnl_lock();
-			ret = dev_ifsioc(net, ifr, cmd);
+			ret = dev_ifsioc(net, ifr, data, cmd);
 			rtnl_unlock();
 			return ret;
 		}

net/ethtool/ioctl.c

···
 
 /* The main entry point in this file.  Called from net/core/dev_ioctl.c */
 
-int dev_ethtool(struct net *net, struct ifreq *ifr)
+int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
 {
 	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
-	void __user *useraddr = ifr->ifr_data;
 	u32 ethcmd, sub_cmd;
 	int rc;
 	netdev_features_t old_features;

net/socket.c

···
 	bool need_copyout;
 	int err;
 	void __user *argp = (void __user *)arg;
+	void __user *data;
 
 	err = sock->ops->ioctl(sock, cmd, arg);
 
···
 	if (err != -ENOIOCTLCMD)
 		return err;
 
-	if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
+	if (get_user_ifreq(&ifr, &data, argp))
 		return -EFAULT;
-	err = dev_ioctl(net, cmd, &ifr, &need_copyout);
+	err = dev_ioctl(net, cmd, &ifr, data, &need_copyout);
 	if (!err && need_copyout)
-		if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
+		if (put_user_ifreq(&ifr, argp))
 			return -EFAULT;
 
 	return err;
···
 	net = sock_net(sk);
 	if (unlikely(cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15))) {
 		struct ifreq ifr;
+		void __user *data;
 		bool need_copyout;
-		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
+		if (get_user_ifreq(&ifr, &data, argp))
 			return -EFAULT;
-		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
+		err = dev_ioctl(net, cmd, &ifr, data, &need_copyout);
 		if (!err && need_copyout)
-			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
+			if (put_user_ifreq(&ifr, argp))
 				return -EFAULT;
 	} else
 #ifdef CONFIG_WEXT_CORE
···
 	saved = ifr.ifr_settings.ifs_ifsu.raw_hdlc;
 	ifr.ifr_settings.ifs_ifsu.raw_hdlc = compat_ptr(uptr32);
 
-	err = dev_ioctl(net, SIOCWANDEV, &ifr, NULL);
+	err = dev_ioctl(net, SIOCWANDEV, &ifr, NULL, NULL);
 	if (!err) {
 		ifr.ifr_settings.ifs_ifsu.raw_hdlc = saved;
 		if (put_user_ifreq(&ifr, uifr32))
···
 				 struct compat_ifreq __user *u_ifreq32)
 {
 	struct ifreq ifreq;
-	u32 data32;
+	void __user *data;
 
-	if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ))
+	if (get_user_ifreq(&ifreq, &data, u_ifreq32))
 		return -EFAULT;
-	if (get_user(data32, &u_ifreq32->ifr_data))
-		return -EFAULT;
-	ifreq.ifr_data = compat_ptr(data32);
+	ifreq.ifr_data = data;
 
-	return dev_ioctl(net, cmd, &ifreq, NULL);
-}
-
-static int compat_ifreq_ioctl(struct net *net, struct socket *sock,
-			      unsigned int cmd,
-			      unsigned long arg,
-			      struct compat_ifreq __user *uifr32)
-{
-	struct ifreq ifr;
-	bool need_copyout;
-	int err;
-
-	err = sock->ops->ioctl(sock, cmd, arg);
-
-	/* If this ioctl is unknown try to hand it down
-	 * to the NIC driver.
-	 */
-	if (err != -ENOIOCTLCMD)
-		return err;
-
-	if (get_user_ifreq(&ifr, NULL, uifr32))
-		return -EFAULT;
-	err = dev_ioctl(net, cmd, &ifr, &need_copyout);
-	if (!err && need_copyout)
-		if (put_user_ifreq(&ifr, uifr32))
-			return -EFAULT;
-
-	return err;
+	return dev_ioctl(net, cmd, &ifreq, data, NULL);
 }
 
 /* Since old style bridge ioctl's endup using SIOCDEVPRIVATE
···
 	case SIOCBONDRELEASE:
 	case SIOCBONDSETHWADDR:
 	case SIOCBONDCHANGEACTIVE:
-		return compat_ifreq_ioctl(net, sock, cmd, arg, argp);
-
 	case SIOCSARP:
 	case SIOCGARP:
 	case SIOCDARP: