From: Arnd Bergmann <a...@arndb.de>

The dev_ifconf() calling conventions make compat handling
more complicated than necessary, simplify this by moving
the in_compat_syscall() check into the function.
The implementation can be simplified further, based on the
knowledge that the dynamic registration is only ever used
for IPv4.

Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 include/linux/inetdevice.h |  8 ++++
 include/linux/netdevice.h  | 10 +----
 net/core/dev_ioctl.c       | 92 +++++++++++++++-----------------------
 net/ipv4/devinet.c         |  4 +-
 net/socket.c               | 59 ++++++------------------
 5 files changed, 60 insertions(+), 113 deletions(-)

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 3515ca64e638..e8a957ca80f8 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -178,6 +178,14 @@ static inline struct net_device *ip_dev_find(struct net 
*net, __be32 addr)
 
 int inet_addr_onlink(struct in_device *in_dev, __be32 a, __be32 b);
 int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *);
+#ifdef CONFIG_INET
+int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size);
+#else
+static inline inet_gifconf(struct net_device *dev, char __user *buf, int len, 
int size)
+{
+       return 0;
+}
+#endif
 void devinet_init(void);
 struct in_device *inetdev_by_index(struct net *, int);
 __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 964b494b0e8d..b54d5308087d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3137,14 +3137,6 @@ static inline bool dev_validate_header(const struct 
net_device *dev,
        return false;
 }
 
-typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr,
-                          int len, int size);
-int register_gifconf(unsigned int family, gifconf_func_t *gifconf);
-static inline int unregister_gifconf(unsigned int family)
-{
-       return register_gifconf(family, NULL);
-}
-
 #ifdef CONFIG_NET_FLOW_LIMIT
 #define FLOW_LIMIT_HISTORY     (1 << 7)  /* must be ^2 and !overflow buckets */
 struct sd_flow_limit {
@@ -3837,7 +3829,7 @@ 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, struct ifreq *ifr,
                bool *need_copyout);
-int dev_ifconf(struct net *net, struct ifconf *, int);
+int dev_ifconf(struct net *net, struct ifconf __user *ifc);
 int dev_ethtool(struct net *net, struct ifreq *);
 unsigned int dev_get_flags(const struct net_device *);
 int __dev_change_flags(struct net_device *dev, unsigned int flags,
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 1c6da044754a..5822737a78f4 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/kmod.h>
 #include <linux/netdevice.h>
+#include <linux/inetdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/net_tstamp.h>
@@ -25,77 +26,56 @@ static int dev_ifname(struct net *net, struct ifreq *ifr)
        return netdev_get_name(net, ifr->ifr_name, ifr->ifr_ifindex);
 }
 
-static gifconf_func_t *gifconf_list[NPROTO];
-
-/**
- *     register_gifconf        -       register a SIOCGIF handler
- *     @family: Address family
- *     @gifconf: Function handler
- *
- *     Register protocol dependent address dumping routines. The handler
- *     that is passed must not be freed or reused until it has been replaced
- *     by another handler.
- */
-int register_gifconf(unsigned int family, gifconf_func_t *gifconf)
-{
-       if (family >= NPROTO)
-               return -EINVAL;
-       gifconf_list[family] = gifconf;
-       return 0;
-}
-EXPORT_SYMBOL(register_gifconf);
-
 /*
  *     Perform a SIOCGIFCONF call. This structure will change
  *     size eventually, and there is nothing I can do about it.
  *     Thus we will need a 'compatibility mode'.
  */
-
-int dev_ifconf(struct net *net, struct ifconf *ifc, int size)
+int dev_ifconf(struct net *net, struct ifconf __user *uifc)
 {
        struct net_device *dev;
-       char __user *pos;
-       int len;
-       int total;
-       int i;
+       void __user *pos;
+       size_t size;
+       int len, total = 0, done;
 
-       /*
-        *      Fetch the caller's info block.
-        */
+       /* both the ifconf and the ifreq structures are slightly different */
+       if (in_compat_syscall()) {
+               struct compat_ifconf ifc32;
 
-       pos = ifc->ifc_buf;
-       len = ifc->ifc_len;
+               if (copy_from_user(&ifc32, uifc, sizeof(struct compat_ifconf)))
+                       return -EFAULT;
 
-       /*
-        *      Loop over the interfaces, and write an info block for each.
-        */
+               pos = compat_ptr(ifc32.ifcbuf);
+               len = ifc32.ifc_len;
+               size = sizeof(struct compat_ifreq);
+       } else {
+               struct ifconf ifc;
 
-       total = 0;
+               if (copy_from_user(&ifc, uifc, sizeof(struct ifconf)))
+                       return -EFAULT;
+
+               pos = ifc.ifc_buf;
+               len = ifc.ifc_len;
+               size = sizeof(struct ifreq);
+       }
+
+       /* Loop over the interfaces, and write an info block for each. */
+       rtnl_lock();
        for_each_netdev(net, dev) {
-               for (i = 0; i < NPROTO; i++) {
-                       if (gifconf_list[i]) {
-                               int done;
-                               if (!pos)
-                                       done = gifconf_list[i](dev, NULL, 0, 
size);
-                               else
-                                       done = gifconf_list[i](dev, pos + total,
-                                                              len - total, 
size);
-                               if (done < 0)
-                                       return -EFAULT;
-                               total += done;
-                       }
+               if (!pos)
+                       done = inet_gifconf(dev, NULL, 0, size);
+               else
+                       done = inet_gifconf(dev, pos + total,
+                                           len - total, size);
+               if (done < 0) {
+                       rtnl_unlock();
+                       return -EFAULT;
                }
+               total += done;
        }
+       rtnl_unlock();
 
-       /*
-        *      All done.  Write the updated control block back to the caller.
-        */
-       ifc->ifc_len = total;
-
-       /*
-        *      Both BSD and Solaris return 0 here, so we do too.
-        */
-       return 0;
+       return put_user(total, &uifc->ifc_len);
 }
 
 static int dev_getifmap(struct net_device *dev, struct ifreq *ifr)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 123a6d39438f..3e910dedcb80 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1244,7 +1244,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, 
struct ifreq *ifr)
        return ret;
 }
 
-static int inet_gifconf(struct net_device *dev, char __user *buf, int len, int 
size)
+int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size)
 {
        struct in_device *in_dev = __in_dev_get_rtnl(dev);
        const struct in_ifaddr *ifa;
@@ -2762,8 +2762,6 @@ void __init devinet_init(void)
                INIT_HLIST_HEAD(&inet_addr_lst[i]);
 
        register_pernet_subsys(&devinet_ops);
-
-       register_gifconf(PF_INET, inet_gifconf);
        register_netdevice_notifier(&ip_netdev_notifier);
 
        queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);
diff --git a/net/socket.c b/net/socket.c
index 2b58b1d87cad..f26ef299b6c5 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1041,6 +1041,8 @@ EXPORT_SYMBOL(dlci_ioctl_set);
 static long sock_do_ioctl(struct net *net, struct socket *sock,
                          unsigned int cmd, unsigned long arg)
 {
+       struct ifreq ifr;
+       bool need_copyout;
        int err;
        void __user *argp = (void __user *)arg;
 
@@ -1053,25 +1055,13 @@ static long sock_do_ioctl(struct net *net, struct 
socket *sock,
        if (err != -ENOIOCTLCMD)
                return err;
 
-       if (cmd == SIOCGIFCONF) {
-               struct ifconf ifc;
-               if (copy_from_user(&ifc, argp, sizeof(struct ifconf)))
-                       return -EFAULT;
-               rtnl_lock();
-               err = dev_ifconf(net, &ifc, sizeof(struct ifreq));
-               rtnl_unlock();
-               if (!err && copy_to_user(argp, &ifc, sizeof(struct ifconf)))
-                       err = -EFAULT;
-       } else {
-               struct ifreq ifr;
-               bool need_copyout;
-               if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
+       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;
-               err = dev_ioctl(net, cmd, &ifr, &need_copyout);
-               if (!err && need_copyout)
-                       if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
-                               return -EFAULT;
-       }
+
        return err;
 }
 
@@ -1194,6 +1184,11 @@ static long sock_ioctl(struct file *file, unsigned cmd, 
unsigned long arg)
                                                   cmd == SIOCGSTAMP_NEW,
                                                   false);
                        break;
+
+               case SIOCGIFCONF:
+                       err = dev_ifconf(net, argp);
+                       break;
+
                default:
                        err = sock_do_ioctl(net, sock, cmd, arg);
                        break;
@@ -3098,31 +3093,6 @@ void socket_seq_show(struct seq_file *seq)
 #endif                         /* CONFIG_PROC_FS */
 
 #ifdef CONFIG_COMPAT
-static int compat_dev_ifconf(struct net *net, struct compat_ifconf __user 
*uifc32)
-{
-       struct compat_ifconf ifc32;
-       struct ifconf ifc;
-       int err;
-
-       if (copy_from_user(&ifc32, uifc32, sizeof(struct compat_ifconf)))
-               return -EFAULT;
-
-       ifc.ifc_len = ifc32.ifc_len;
-       ifc.ifc_req = compat_ptr(ifc32.ifcbuf);
-
-       rtnl_lock();
-       err = dev_ifconf(net, &ifc, sizeof(struct compat_ifreq));
-       rtnl_unlock();
-       if (err)
-               return err;
-
-       ifc32.ifc_len = ifc.ifc_len;
-       if (copy_to_user(uifc32, &ifc32, sizeof(struct compat_ifconf)))
-               return -EFAULT;
-
-       return 0;
-}
-
 static int compat_siocwandev(struct net *net, struct compat_ifreq __user 
*uifr32)
 {
        compat_uptr_t uptr32;
@@ -3241,8 +3211,6 @@ static int compat_sock_ioctl_trans(struct file *file, 
struct socket *sock,
        case SIOCSIFBR:
        case SIOCGIFBR:
                return old_bridge_ioctl(argp);
-       case SIOCGIFCONF:
-               return compat_dev_ifconf(net, argp);
        case SIOCWANDEV:
                return compat_siocwandev(net, argp);
        case SIOCGSTAMP_OLD:
@@ -3272,6 +3240,7 @@ static int compat_sock_ioctl_trans(struct file *file, 
struct socket *sock,
        case SIOCGSKNS:
        case SIOCGSTAMP_NEW:
        case SIOCGSTAMPNS_NEW:
+       case SIOCGIFCONF:
                return sock_ioctl(file, cmd, arg);
 
        case SIOCGIFFLAGS:
-- 
2.27.0

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