dev_ioctl(): move copyin/copyout to callers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/netdevice.h

@@ -3315,7 +3315,8 @@ int netdev_rx_handler_register(struct net_device *dev,
 void netdev_rx_handler_unregister(struct net_device *dev);
 
 bool dev_valid_name(const char *name);
-int dev_ioctl(struct net *net, unsigned int cmd, void __user *);
+int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr,
+		bool *need_copyout);
 int dev_ifconf(struct net *net, struct ifconf *, int);
 int dev_ethtool(struct net *net, struct ifreq *);
 unsigned int dev_get_flags(const struct net_device *);

net/core/dev_ioctl.c

@@ -18,26 +18,10 @@
  *	match.  --pb
  */
 
-static int dev_ifname(struct net *net, struct ifreq __user *arg)
+static int dev_ifname(struct net *net, struct ifreq *ifr)
 {
-	struct ifreq ifr;
-	int error;
-
-	/*
-	 *	Fetch the caller's info block.
-	 */
-
-	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
-		return -EFAULT;
-	ifr.ifr_name[IFNAMSIZ-1] = 0;
-
-	error = netdev_get_name(net, ifr.ifr_name, ifr.ifr_ifindex);
-	if (error)
-		return error;
-
-	if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
-		return -EFAULT;
-	return 0;
+	ifr->ifr_name[IFNAMSIZ-1] = 0;
+	return netdev_get_name(net, ifr->ifr_name, ifr->ifr_ifindex);
 }
 
 static gifconf_func_t *gifconf_list[NPROTO];
@@ -402,24 +386,24 @@ EXPORT_SYMBOL(dev_load);
  *	positive or a negative errno code on error.
  */
 
-int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
+int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_copyout)
 {
-	struct ifreq ifr;
 	int ret;
 	char *colon;
 
+	if (need_copyout)
+		*need_copyout = true;
 	if (cmd == SIOCGIFNAME)
-		return dev_ifname(net, (struct ifreq __user *)arg);
-
-	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
-		return -EFAULT;
+		return dev_ifname(net, ifr);
 
-	ifr.ifr_name[IFNAMSIZ-1] = 0;
+	ifr->ifr_name[IFNAMSIZ-1] = 0;
 
-	colon = strchr(ifr.ifr_name, ':');
+	colon = strchr(ifr->ifr_name, ':');
 	if (colon)
 		*colon = 0;
 
+	dev_load(net, ifr->ifr_name);
+
 	/*
 	 *	See which interface the caller is talking about.
 	 */
@@ -439,31 +423,19 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 	case SIOCGIFMAP:
 	case SIOCGIFINDEX:
 	case SIOCGIFTXQLEN:
-		dev_load(net, ifr.ifr_name);
 		rcu_read_lock();
-		ret = dev_ifsioc_locked(net, &ifr, cmd);
+		ret = dev_ifsioc_locked(net, ifr, cmd);
 		rcu_read_unlock();
-		if (!ret) {
-			if (colon)
-				*colon = ':';
-			if (copy_to_user(arg, &ifr,
-					 sizeof(struct ifreq)))
-				ret = -EFAULT;
-		}
+		if (colon)
+			*colon = ':';
 		return ret;
 
 	case SIOCETHTOOL:
-		dev_load(net, ifr.ifr_name);
 		rtnl_lock();
-		ret = dev_ethtool(net, &ifr);
+		ret = dev_ethtool(net, ifr);
 		rtnl_unlock();
-		if (!ret) {
-			if (colon)
-				*colon = ':';
-			if (copy_to_user(arg, &ifr,
-					 sizeof(struct ifreq)))
-				ret = -EFAULT;
-		}
+		if (colon)
+			*colon = ':';
 		return ret;
 
 	/*
@@ -477,17 +449,11 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 	case SIOCSIFNAME:
 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			return -EPERM;
-		dev_load(net, ifr.ifr_name);
 		rtnl_lock();
-		ret = dev_ifsioc(net, &ifr, cmd);
+		ret = dev_ifsioc(net, ifr, cmd);
 		rtnl_unlock();
-		if (!ret) {
-			if (colon)
-				*colon = ':';
-			if (copy_to_user(arg, &ifr,
-					 sizeof(struct ifreq)))
-				ret = -EFAULT;
-		}
+		if (colon)
+			*colon = ':';
 		return ret;
 
 	/*
@@ -528,10 +494,11 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 		/* fall through */
 	case SIOCBONDSLAVEINFOQUERY:
 	case SIOCBONDINFOQUERY:
-		dev_load(net, ifr.ifr_name);
 		rtnl_lock();
-		ret = dev_ifsioc(net, &ifr, cmd);
+		ret = dev_ifsioc(net, ifr, cmd);
 		rtnl_unlock();
+		if (need_copyout)
+			*need_copyout = false;
 		return ret;
 
 	case SIOCGIFMEM:
@@ -551,13 +518,9 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
 		    cmd == SIOCGHWTSTAMP ||
 		    (cmd >= SIOCDEVPRIVATE &&
 		     cmd <= SIOCDEVPRIVATE + 15)) {
-			dev_load(net, ifr.ifr_name);
 			rtnl_lock();
-			ret = dev_ifsioc(net, &ifr, cmd);
+			ret = dev_ifsioc(net, ifr, cmd);
 			rtnl_unlock();
-			if (!ret && copy_to_user(arg, &ifr,
-						 sizeof(struct ifreq)))
-				ret = -EFAULT;
 			return ret;
 		}
 		return -ENOTTY;

net/socket.c

@@ -973,10 +973,17 @@ static long sock_do_ioctl(struct net *net, struct socket *sock,
 		rtnl_unlock();
 		if (!err && copy_to_user(argp, &ifc, sizeof(struct ifconf)))
 			err = -EFAULT;
-		return err;
+	} else {
+		struct ifreq ifr;
+		bool need_copyout;
+		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
+			return -EFAULT;
+		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
+		if (!err && need_copyout)
+			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
+				return -EFAULT;
 	}
-
-	return dev_ioctl(net, cmd, argp);
+	return err;
 }
 
 /*
@@ -1000,8 +1007,15 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	sock = file->private_data;
 	sk = sock->sk;
 	net = sock_net(sk);
-	if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
-		err = dev_ioctl(net, cmd, argp);
+	if (unlikely(cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15))) {
+		struct ifreq ifr;
+		bool need_copyout;
+		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
+			return -EFAULT;
+		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
+		if (!err && need_copyout)
+			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
+				return -EFAULT;
 	} else
 #ifdef CONFIG_WEXT_CORE
 	if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
@@ -2695,9 +2709,9 @@ static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
 {
 	struct compat_ethtool_rxnfc __user *compat_rxnfc;
 	bool convert_in = false, convert_out = false;
-	size_t buf_size = ALIGN(sizeof(struct ifreq), 8);
-	struct ethtool_rxnfc __user *rxnfc;
-	struct ifreq __user *ifr;
+	size_t buf_size = 0;
+	struct ethtool_rxnfc __user *rxnfc = NULL;
+	struct ifreq ifr;
 	u32 rule_cnt = 0, actual_rule_cnt;
 	u32 ethcmd;
 	u32 data;
@@ -2734,18 +2748,14 @@ static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
 	case ETHTOOL_SRXCLSRLDEL:
 		buf_size += sizeof(struct ethtool_rxnfc);
 		convert_in = true;
+		rxnfc = compat_alloc_user_space(buf_size);
 		break;
 	}
 
-	ifr = compat_alloc_user_space(buf_size);
-	rxnfc = (void __user *)ifr + ALIGN(sizeof(struct ifreq), 8);
-
-	if (copy_in_user(&ifr->ifr_name, &ifr32->ifr_name, IFNAMSIZ))
+	if (copy_from_user(&ifr.ifr_name, &ifr32->ifr_name, IFNAMSIZ))
 		return -EFAULT;
 
-	if (put_user(convert_in ? rxnfc : compat_ptr(data),
-		     &ifr->ifr_ifru.ifru_data))
-		return -EFAULT;
+	ifr.ifr_data = convert_in ? rxnfc : (void __user *)compat_rxnfc;
 
 	if (convert_in) {
 		/* We expect there to be holes between fs.m_ext and
@@ -2773,7 +2783,7 @@ static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
 			return -EFAULT;
 	}
 
-	ret = dev_ioctl(net, SIOCETHTOOL, ifr);
+	ret = dev_ioctl(net, SIOCETHTOOL, &ifr, NULL);
 	if (ret)
 		return ret;
 
@@ -2814,50 +2824,43 @@ static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
 
 static int compat_siocwandev(struct net *net, struct compat_ifreq __user *uifr32)
 {
-	void __user *uptr;
 	compat_uptr_t uptr32;
-	struct ifreq __user *uifr;
+	struct ifreq ifr;
+	void __user *saved;
+	int err;
 
-	uifr = compat_alloc_user_space(sizeof(*uifr));
-	if (copy_in_user(uifr, uifr32, sizeof(struct compat_ifreq)))
+	if (copy_from_user(&ifr, uifr32, sizeof(struct compat_ifreq)))
 		return -EFAULT;
 
 	if (get_user(uptr32, &uifr32->ifr_settings.ifs_ifsu))
 		return -EFAULT;
 
-	uptr = compat_ptr(uptr32);
-
-	if (put_user(uptr, &uifr->ifr_settings.ifs_ifsu.raw_hdlc))
-		return -EFAULT;
+	saved = ifr.ifr_settings.ifs_ifsu.raw_hdlc;
+	ifr.ifr_settings.ifs_ifsu.raw_hdlc = compat_ptr(uptr32);
 
-	return dev_ioctl(net, SIOCWANDEV, uifr);
+	err = dev_ioctl(net, SIOCWANDEV, &ifr, NULL);
+	if (!err) {
+		ifr.ifr_settings.ifs_ifsu.raw_hdlc = saved;
+		if (copy_to_user(uifr32, &ifr, sizeof(struct compat_ifreq)))
+			err = -EFAULT;
+	}
+	return err;
 }
 
 /* Handle ioctls that use ifreq::ifr_data and just need struct ifreq converted */
 static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd,
 				 struct compat_ifreq __user *u_ifreq32)
 {
-	struct ifreq __user *u_ifreq64;
-	char tmp_buf[IFNAMSIZ];
-	void __user *data64;
+	struct ifreq ifreq;
 	u32 data32;
 
-	if (copy_from_user(&tmp_buf[0], &(u_ifreq32->ifr_ifrn.ifrn_name[0]),
-			   IFNAMSIZ))
+	if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ))
 		return -EFAULT;
-	if (get_user(data32, &u_ifreq32->ifr_ifru.ifru_data))
+	if (get_user(data32, &u_ifreq32->ifr_data))
 		return -EFAULT;
-	data64 = compat_ptr(data32);
+	ifreq.ifr_data = compat_ptr(data32);
 
-	u_ifreq64 = compat_alloc_user_space(sizeof(*u_ifreq64));
-
-	if (copy_to_user(&u_ifreq64->ifr_ifrn.ifrn_name[0], &tmp_buf[0],
-			 IFNAMSIZ))
-		return -EFAULT;
-	if (put_user(data64, &u_ifreq64->ifr_ifru.ifru_data))
-		return -EFAULT;
-
-	return dev_ioctl(net, cmd, u_ifreq64);
+	return dev_ioctl(net, cmd, &ifreq, NULL);
 }
 
 static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
@@ -2865,7 +2868,6 @@ static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
 {
 	struct ifreq ifr;
 	struct compat_ifmap __user *uifmap32;
-	mm_segment_t old_fs;
 	int err;
 
 	uifmap32 = &uifr32->ifr_ifru.ifru_map;
@@ -2879,10 +2881,7 @@ static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
 	if (err)
 		return -EFAULT;
 
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	err = dev_ioctl(net, cmd, (void  __user __force *)&ifr);
-	set_fs(old_fs);
+	err = dev_ioctl(net, cmd, &ifr, NULL);
 
 	if (cmd == SIOCGIFMAP && !err) {
 		err = copy_to_user(uifr32, &ifr, sizeof(ifr.ifr_name));