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    Subject[PATCH net-next v3 3/4] net: socket: simplify dev_ifconf handling
    Date
    From: Arnd Bergmann <arnd@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 <arnd@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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      Last update: 2020-11-06 18:33    [W:4.656 / U:0.012 seconds]
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