tun: Fix minor race in TUNSETLINK ioctl handling.
[safe/jmp/linux-2.6] / drivers / net / tun.c
index a57aa01..d8b1ba1 100644 (file)
 /*
  *  Changes:
  *
+ *  Brian Braunstein <linuxkernel@bristyle.com> 2007/03/23
+ *    Fixed hw address handling.  Now net_device.dev_addr is kept consistent
+ *    with tun.dev_addr when the address is set by this module.
+ *
  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  *    Add TUNSETLINK ioctl to set the link encapsulation
  *
 #include <linux/if_ether.h>
 #include <linux/if_tun.h>
 #include <linux/crc32.h>
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
 
+/* Uncomment to enable debugging */
+/* #define TUN_DEBUG 1 */
+
 #ifdef TUN_DEBUG
 static int debug;
+
+#define DBG  if(tun->debug)printk
+#define DBG1 if(debug==2)printk
+#else
+#define DBG( a... )
+#define DBG1( a... )
 #endif
 
+struct tun_struct {
+       struct list_head        list;
+       unsigned long           flags;
+       int                     attached;
+       uid_t                   owner;
+       gid_t                   group;
+
+       wait_queue_head_t       read_wait;
+       struct sk_buff_head     readq;
+
+       struct net_device       *dev;
+
+       struct fasync_struct    *fasync;
+
+       unsigned long if_flags;
+       u8 dev_addr[ETH_ALEN];
+       u32 chr_filter[2];
+       u32 net_filter[2];
+
+#ifdef TUN_DEBUG
+       int debug;
+#endif
+};
+
 /* Network device part of the driver */
 
-static LIST_HEAD(tun_dev_list);
+static unsigned int tun_net_id;
+struct tun_net {
+       struct list_head dev_list;
+};
+
 static const struct ethtool_ops tun_ethtool_ops;
 
 /* Net device open. */
@@ -105,7 +149,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 
                        /* We won't see all dropped packets individually, so overrun
                         * error is more appropriate. */
-                       tun->stats.tx_fifo_errors++;
+                       dev->stats.tx_fifo_errors++;
                } else {
                        /* Single queue mode.
                         * Driver handles dropping of all packets itself. */
@@ -124,7 +168,7 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
        return 0;
 
 drop:
-       tun->stats.tx_dropped++;
+       dev->stats.tx_dropped++;
        kfree_skb(skb);
        return 0;
 }
@@ -154,23 +198,28 @@ tun_net_mclist(struct net_device *dev)
        struct tun_struct *tun = netdev_priv(dev);
        const struct dev_mc_list *mclist;
        int i;
+       DECLARE_MAC_BUF(mac);
        DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
                        dev->name, dev->mc_count);
        memset(tun->chr_filter, 0, sizeof tun->chr_filter);
        for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
                        i++, mclist = mclist->next) {
                add_multi(tun->net_filter, mclist->dmi_addr);
-               DBG(KERN_DEBUG "%s: tun_net_mclist: %x:%x:%x:%x:%x:%x\n",
-                               dev->name,
-                               mclist->dmi_addr[0], mclist->dmi_addr[1], mclist->dmi_addr[2],
-                               mclist->dmi_addr[3], mclist->dmi_addr[4], mclist->dmi_addr[5]);
+               DBG(KERN_DEBUG "%s: tun_net_mclist: %s\n",
+                   dev->name, print_mac(mac, mclist->dmi_addr));
        }
 }
 
-static struct net_device_stats *tun_net_stats(struct net_device *dev)
+#define MIN_MTU 68
+#define MAX_MTU 65535
+
+static int
+tun_net_change_mtu(struct net_device *dev, int new_mtu)
 {
-       struct tun_struct *tun = netdev_priv(dev);
-       return &tun->stats;
+       if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
+               return -EINVAL;
+       dev->mtu = new_mtu;
+       return 0;
 }
 
 /* Initialize net device. */
@@ -184,6 +233,7 @@ static void tun_net_init(struct net_device *dev)
                dev->hard_header_len = 0;
                dev->addr_len = 0;
                dev->mtu = 1500;
+               dev->change_mtu = tun_net_change_mtu;
 
                /* Zero header length */
                dev->type = ARPHRD_NONE;
@@ -196,7 +246,11 @@ static void tun_net_init(struct net_device *dev)
                dev->set_multicast_list = tun_net_mclist;
 
                ether_setup(dev);
-               random_ether_addr(dev->dev_addr);
+               dev->change_mtu = tun_net_change_mtu;
+
+               /* random address already created for us by tun_set_iff, use it */
+               memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) );
+
                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
                break;
        }
@@ -238,25 +292,28 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
                        return -EFAULT;
        }
 
-       if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
+       if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
                align = NET_IP_ALIGN;
+               if (unlikely(len < ETH_HLEN))
+                       return -EINVAL;
+       }
 
        if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
-               tun->stats.rx_dropped++;
+               tun->dev->stats.rx_dropped++;
                return -ENOMEM;
        }
 
        if (align)
                skb_reserve(skb, align);
        if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
-               tun->stats.rx_dropped++;
+               tun->dev->stats.rx_dropped++;
                kfree_skb(skb);
                return -EFAULT;
        }
 
        switch (tun->flags & TUN_TYPE_MASK) {
        case TUN_TUN_DEV:
-               skb->mac.raw = skb->data;
+               skb_reset_mac_header(skb);
                skb->protocol = pi.proto;
                skb->dev = tun->dev;
                break;
@@ -271,23 +328,12 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
        netif_rx_ni(skb);
        tun->dev->last_rx = jiffies;
 
-       tun->stats.rx_packets++;
-       tun->stats.rx_bytes += len;
+       tun->dev->stats.rx_packets++;
+       tun->dev->stats.rx_bytes += len;
 
        return count;
 }
 
-static inline size_t iov_total(const struct iovec *iv, unsigned long count)
-{
-       unsigned long i;
-       size_t len;
-
-       for (i = 0, len = 0; i < count; i++)
-               len += iv[i].iov_len;
-
-       return len;
-}
-
 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
                              unsigned long count, loff_t pos)
 {
@@ -298,7 +344,7 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 
        DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 
-       return tun_get_user(tun, (struct iovec *) iv, iov_total(iv, count));
+       return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
 }
 
 /* Put packet to the user space buffer */
@@ -328,8 +374,8 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
        skb_copy_datagram_iovec(skb, 0, iv, len);
        total += len;
 
-       tun->stats.tx_packets++;
-       tun->stats.tx_bytes += len;
+       tun->dev->stats.tx_packets++;
+       tun->dev->stats.tx_bytes += len;
 
        return total;
 }
@@ -342,13 +388,14 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
        DECLARE_WAITQUEUE(wait, current);
        struct sk_buff *skb;
        ssize_t len, ret = 0;
+       DECLARE_MAC_BUF(mac);
 
        if (!tun)
                return -EBADFD;
 
        DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 
-       len = iov_total(iv, count);
+       len = iov_length(iv, count);
        if (len < 0)
                return -EINVAL;
 
@@ -386,8 +433,8 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                 *   - we are multicast promiscous.
                 *   - we belong to the multicast group.
                 */
-               memcpy(addr, skb->data,
-                      min_t(size_t, sizeof addr, skb->len));
+               skb_copy_from_linear_data(skb, addr, min_t(size_t, sizeof addr,
+                                                                  skb->len));
                bit_nr = ether_crc(sizeof addr, addr) >> 26;
                if ((tun->if_flags & IFF_PROMISC) ||
                                memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
@@ -396,16 +443,14 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                                  (addr[0] == 0x33 && addr[1] == 0x33)) &&
                                 ((tun->if_flags & IFF_ALLMULTI) ||
                                  (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
-                       DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %x:%x:%x:%x:%x:%x\n",
-                                       tun->dev->name, addr[0], addr[1], addr[2],
-                                       addr[3], addr[4], addr[5]);
+                       DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %s\n",
+                                       tun->dev->name, print_mac(mac, addr));
                        ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
                        kfree_skb(skb);
                        break;
                } else {
-                       DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %x:%x:%x:%x:%x:%x\n",
-                                       tun->dev->name, addr[0], addr[1], addr[2],
-                                       addr[3], addr[4], addr[5]);
+                       DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n",
+                                       tun->dev->name, print_mac(mac, addr));
                        kfree_skb(skb);
                        continue;
                }
@@ -425,22 +470,22 @@ static void tun_setup(struct net_device *dev)
        init_waitqueue_head(&tun->read_wait);
 
        tun->owner = -1;
+       tun->group = -1;
 
-       SET_MODULE_OWNER(dev);
        dev->open = tun_net_open;
        dev->hard_start_xmit = tun_net_xmit;
        dev->stop = tun_net_close;
-       dev->get_stats = tun_net_stats;
        dev->ethtool_ops = &tun_ethtool_ops;
        dev->destructor = free_netdev;
+       dev->features |= NETIF_F_NETNS_LOCAL;
 }
 
-static struct tun_struct *tun_get_by_name(const char *name)
+static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
 {
        struct tun_struct *tun;
 
        ASSERT_RTNL();
-       list_for_each_entry(tun, &tun_dev_list, list) {
+       list_for_each_entry(tun, &tn->dev_list, list) {
                if (!strncmp(tun->dev->name, name, IFNAMSIZ))
                    return tun;
        }
@@ -448,23 +493,28 @@ static struct tun_struct *tun_get_by_name(const char *name)
        return NULL;
 }
 
-static int tun_set_iff(struct file *file, struct ifreq *ifr)
+static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 {
+       struct tun_net *tn;
        struct tun_struct *tun;
        struct net_device *dev;
        int err;
 
-       tun = tun_get_by_name(ifr->ifr_name);
+       tn = net_generic(net, tun_net_id);
+       tun = tun_get_by_name(tn, ifr->ifr_name);
        if (tun) {
                if (tun->attached)
                        return -EBUSY;
 
                /* Check permissions */
-               if (tun->owner != -1 &&
-                   current->euid != tun->owner && !capable(CAP_NET_ADMIN))
+               if (((tun->owner != -1 &&
+                     current->euid != tun->owner) ||
+                    (tun->group != -1 &&
+                     current->egid != tun->group)) &&
+                    !capable(CAP_NET_ADMIN))
                        return -EPERM;
        }
-       else if (__dev_get_by_name(ifr->ifr_name))
+       else if (__dev_get_by_name(net, ifr->ifr_name))
                return -EINVAL;
        else {
                char *name;
@@ -495,13 +545,14 @@ static int tun_set_iff(struct file *file, struct ifreq *ifr)
                if (!dev)
                        return -ENOMEM;
 
+               dev_net_set(dev, net);
                tun = netdev_priv(dev);
                tun->dev = dev;
                tun->flags = flags;
                /* Be promiscuous by default to maintain previous behaviour. */
                tun->if_flags = IFF_PROMISC;
                /* Generate random Ethernet address. */
-               *(u16 *)tun->dev_addr = htons(0x00FF);
+               *(__be16 *)tun->dev_addr = htons(0x00FF);
                get_random_bytes(tun->dev_addr + sizeof(u16), 4);
                memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 
@@ -517,19 +568,24 @@ static int tun_set_iff(struct file *file, struct ifreq *ifr)
                if (err < 0)
                        goto err_free_dev;
 
-               list_add(&tun->list, &tun_dev_list);
+               list_add(&tun->list, &tn->dev_list);
        }
 
        DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 
        if (ifr->ifr_flags & IFF_NO_PI)
                tun->flags |= TUN_NO_PI;
+       else
+               tun->flags &= ~TUN_NO_PI;
 
        if (ifr->ifr_flags & IFF_ONE_QUEUE)
                tun->flags |= TUN_ONE_QUEUE;
+       else
+               tun->flags &= ~TUN_ONE_QUEUE;
 
        file->private_data = tun;
        tun->attached = 1;
+       get_net(dev_net(tun->dev));
 
        strcpy(ifr->ifr_name, tun->dev->name);
        return 0;
@@ -546,6 +602,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
        struct tun_struct *tun = file->private_data;
        void __user* argp = (void __user*)arg;
        struct ifreq ifr;
+       DECLARE_MAC_BUF(mac);
 
        if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
                if (copy_from_user(&ifr, argp, sizeof ifr))
@@ -557,7 +614,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                ifr.ifr_name[IFNAMSIZ-1] = '\0';
 
                rtnl_lock();
-               err = tun_set_iff(file, &ifr);
+               err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
                rtnl_unlock();
 
                if (err)
@@ -593,7 +650,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                        tun->flags &= ~TUN_PERSIST;
 
                DBG(KERN_INFO "%s: persist %s\n",
-                   tun->dev->name, arg ? "disabled" : "enabled");
+                   tun->dev->name, arg ? "enabled" : "disabled");
                break;
 
        case TUNSETOWNER:
@@ -603,17 +660,31 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
                break;
 
+       case TUNSETGROUP:
+               /* Set group of the device */
+               tun->group= (gid_t) arg;
+
+               DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
+               break;
+
        case TUNSETLINK:
+       {
+               int ret;
+
                /* Only allow setting the type when the interface is down */
+               rtnl_lock();
                if (tun->dev->flags & IFF_UP) {
                        DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
                                tun->dev->name);
-                       return -EBUSY;
+                       ret = -EBUSY;
                } else {
                        tun->dev->type = (int) arg;
                        DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
+                       ret = 0;
                }
-               break;
+               rtnl_unlock();
+               return ret;
+       }
 
 #ifdef TUN_DEBUG
        case TUNSETDEBUG:
@@ -636,6 +707,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                return 0;
 
        case SIOCGIFHWADDR:
+               /* Note: the actual net device's address may be different */
                memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
                                min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
                if (copy_to_user( argp, &ifr, sizeof ifr))
@@ -643,37 +715,43 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                return 0;
 
        case SIOCSIFHWADDR:
-               /** Set the character device's hardware address. This is used when
-                * filtering packets being sent from the network device to the character
-                * device. */
-               memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
-                               min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
-               DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
-                               tun->dev->name,
-                               tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
-                               tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
-               return 0;
+       {
+               /* try to set the actual net device's hw address */
+               int ret;
+
+               rtnl_lock();
+               ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
+               rtnl_unlock();
+
+               if (ret == 0) {
+                       /** Set the character device's hardware address. This is used when
+                        * filtering packets being sent from the network device to the character
+                        * device. */
+                       memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
+                                       min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
+                       DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
+                                       tun->dev->name,
+                                       tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
+                                       tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
+               }
+
+               return  ret;
+       }
 
        case SIOCADDMULTI:
                /** Add the specified group to the character device's multicast filter
                 * list. */
                add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
-               DBG(KERN_DEBUG "%s: add multi: %x:%x:%x:%x:%x:%x\n",
-                               tun->dev->name,
-                               (u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
-                               (u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
-                               (u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
+               DBG(KERN_DEBUG "%s: add multi: %s\n",
+                   tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
                return 0;
 
        case SIOCDELMULTI:
                /** Remove the specified group from the character device's multicast
                 * filter list. */
                del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
-               DBG(KERN_DEBUG "%s: del multi: %x:%x:%x:%x:%x:%x\n",
-                               tun->dev->name,
-                               (u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
-                               (u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
-                               (u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
+               DBG(KERN_DEBUG "%s: del multi: %s\n",
+                   tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
                return 0;
 
        default:
@@ -730,6 +808,7 @@ static int tun_chr_close(struct inode *inode, struct file *file)
        /* Detach from net device */
        file->private_data = NULL;
        tun->attached = 0;
+       put_net(dev_net(tun->dev));
 
        /* Drop read queue */
        skb_queue_purge(&tun->readq);
@@ -849,32 +928,76 @@ static const struct ethtool_ops tun_ethtool_ops = {
        .set_rx_csum    = tun_set_rx_csum
 };
 
-static int __init tun_init(void)
+static int tun_init_net(struct net *net)
 {
-       int ret = 0;
+       struct tun_net *tn;
 
-       printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
-       printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
+       tn = kmalloc(sizeof(*tn), GFP_KERNEL);
+       if (tn == NULL)
+               return -ENOMEM;
 
-       ret = misc_register(&tun_miscdev);
-       if (ret)
-               printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
-       return ret;
+       INIT_LIST_HEAD(&tn->dev_list);
+
+       if (net_assign_generic(net, tun_net_id, tn)) {
+               kfree(tn);
+               return -ENOMEM;
+       }
+
+       return 0;
 }
 
-static void tun_cleanup(void)
+static void tun_exit_net(struct net *net)
 {
+       struct tun_net *tn;
        struct tun_struct *tun, *nxt;
 
-       misc_deregister(&tun_miscdev);
+       tn = net_generic(net, tun_net_id);
 
        rtnl_lock();
-       list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
+       list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
                DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
                unregister_netdevice(tun->dev);
        }
        rtnl_unlock();
 
+       kfree(tn);
+}
+
+static struct pernet_operations tun_net_ops = {
+       .init = tun_init_net,
+       .exit = tun_exit_net,
+};
+
+static int __init tun_init(void)
+{
+       int ret = 0;
+
+       printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
+       printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
+
+       ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
+       if (ret) {
+               printk(KERN_ERR "tun: Can't register pernet ops\n");
+               goto err_pernet;
+       }
+
+       ret = misc_register(&tun_miscdev);
+       if (ret) {
+               printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
+               goto err_misc;
+       }
+       return 0;
+
+err_misc:
+       unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
+err_pernet:
+       return ret;
+}
+
+static void tun_cleanup(void)
+{
+       misc_deregister(&tun_miscdev);
+       unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
 }
 
 module_init(tun_init);