[IPV6]: Fix SIOCCHGTUNNEL bug in IPv6 tunnels

A logic bug in tunnel lookup could result in duplicate tunnels when
changing an existing device.

Signed-off-by: Ville Nuorvala <vnuorval@tcs.hut.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 25bc5ed4910456f9dace494e8a55b19bec837e2b..fdf1a2fa3a3d4a4663046260642ba1f59844774c 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -215,11 +215,10 @@ ip6ip6_tnl_unlink(struct ip6_tnl *t)
  *   Create tunnel matching given parameters.
  * 
  * Return: 
- *   0 on success
+ *   created tunnel or NULL
  **/
 
-static int
-ip6_tnl_create(struct ip6_tnl_parm *p, struct ip6_tnl **pt)
+static struct ip6_tnl *ip6_tnl_create(struct ip6_tnl_parm *p)
 {
        struct net_device *dev;
        struct ip6_tnl *t;
@@ -236,11 +235,11 @@ ip6_tnl_create(struct ip6_tnl_parm *p, struct ip6_tnl **pt)
                                break;
                }
                if (i == IP6_TNL_MAX) 
-                       return -ENOBUFS;
+                       goto failed;
        }
        dev = alloc_netdev(sizeof (*t), name, ip6ip6_tnl_dev_setup);
        if (dev == NULL)
-               return -ENOMEM;
+               goto failed;
 
        t = netdev_priv(dev);
        dev->init = ip6ip6_tnl_dev_init;
@@ -248,13 +247,13 @@ ip6_tnl_create(struct ip6_tnl_parm *p, struct ip6_tnl **pt)
 
        if ((err = register_netdevice(dev)) < 0) {
                free_netdev(dev);
-               return err;
+               goto failed;
        }
        dev_hold(dev);
-
        ip6ip6_tnl_link(t);
-       *pt = t;
-       return 0;
+       return t;
+failed:
+       return NULL;
 }
 
 /**
@@ -268,32 +267,23 @@ ip6_tnl_create(struct ip6_tnl_parm *p, struct ip6_tnl **pt)
  *   tunnel device is created and registered for use.
  *
  * Return:
- *   0 if tunnel located or created,
- *   -EINVAL if parameters incorrect,
- *   -ENODEV if no matching tunnel available
+ *   matching tunnel or NULL
  **/
 
-static int
-ip6ip6_tnl_locate(struct ip6_tnl_parm *p, struct ip6_tnl **pt, int create)
+static struct ip6_tnl *ip6ip6_tnl_locate(struct ip6_tnl_parm *p, int create)
 {
        struct in6_addr *remote = &p->raddr;
        struct in6_addr *local = &p->laddr;
        struct ip6_tnl *t;
 
-       if (p->proto != IPPROTO_IPV6)
-               return -EINVAL;
-
        for (t = *ip6ip6_bucket(p); t; t = t->next) {
                if (ipv6_addr_equal(local, &t->parms.laddr) &&
-                   ipv6_addr_equal(remote, &t->parms.raddr)) {
-                       *pt = t;
-                       return (create ? -EEXIST : 0);
-               }
+                   ipv6_addr_equal(remote, &t->parms.raddr))
+                       return t;
        }
        if (!create)
-               return -ENODEV;
-       
-       return ip6_tnl_create(p, pt);
+               return NULL;
+       return ip6_tnl_create(p);
 }
 
 /**
@@ -920,26 +910,20 @@ static int
 ip6ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 {
        int err = 0;
-       int create;
        struct ip6_tnl_parm p;
        struct ip6_tnl *t = NULL;
 
        switch (cmd) {
        case SIOCGETTUNNEL:
                if (dev == ip6ip6_fb_tnl_dev) {
-                       if (copy_from_user(&p,
-                                          ifr->ifr_ifru.ifru_data,
-                                          sizeof (p))) {
+                       if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
                                err = -EFAULT;
                                break;
                        }
-                       if ((err = ip6ip6_tnl_locate(&p, &t, 0)) == -ENODEV)
-                               t = netdev_priv(dev);
-                       else if (err)
-                               break;
-               } else
+                       t = ip6ip6_tnl_locate(&p, 0);
+               }
+               if (t == NULL)
                        t = netdev_priv(dev);
-
                memcpy(&p, &t->parms, sizeof (p));
                if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
                        err = -EFAULT;
@@ -948,35 +932,36 @@ ip6ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
        case SIOCADDTUNNEL:
        case SIOCCHGTUNNEL:
                err = -EPERM;
-               create = (cmd == SIOCADDTUNNEL);
                if (!capable(CAP_NET_ADMIN))
                        break;
-               if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
-                       err = -EFAULT;
+               err = -EFAULT;
+               if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
                        break;
-               }
-               if (!create && dev != ip6ip6_fb_tnl_dev) {
-                       t = netdev_priv(dev);
-               }
-               if (!t && (err = ip6ip6_tnl_locate(&p, &t, create))) {
+               err = -EINVAL;
+               if (p.proto != IPPROTO_IPV6)
                        break;
-               }
-               if (cmd == SIOCCHGTUNNEL) {
-                       if (t->dev != dev) {
-                               err = -EEXIST;
-                               break;
-                       }
+               t = ip6ip6_tnl_locate(&p, cmd == SIOCADDTUNNEL);
+               if (dev != ip6ip6_fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
+                       if (t != NULL) {
+                               if (t->dev != dev) {
+                                       err = -EEXIST;
+                                       break;
+                               }
+                       } else
+                               t = netdev_priv(dev);
+
                        ip6ip6_tnl_unlink(t);
                        err = ip6ip6_tnl_change(t, &p);
                        ip6ip6_tnl_link(t);
                        netdev_state_change(dev);
                }
-               if (copy_to_user(ifr->ifr_ifru.ifru_data,
-                                &t->parms, sizeof (p))) {
-                       err = -EFAULT;
-               } else {
+               if (t) {
                        err = 0;
-               }
+                       if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof (p)))
+                               err = -EFAULT;
+
+               } else
+                       err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
                break;
        case SIOCDELTUNNEL:
                err = -EPERM;
@@ -984,22 +969,18 @@ ip6ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
                        break;
 
                if (dev == ip6ip6_fb_tnl_dev) {
-                       if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
-                                          sizeof (p))) {
-                               err = -EFAULT;
+                       err = -EFAULT;
+                       if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
                                break;
-                       }
-                       err = ip6ip6_tnl_locate(&p, &t, 0);
-                       if (err)
+                       err = -ENOENT;
+                       if ((t = ip6ip6_tnl_locate(&p, 0)) == NULL)
                                break;
-                       if (t == netdev_priv(ip6ip6_fb_tnl_dev)) {
-                               err = -EPERM;
+                       err = -EPERM;
+                       if (t->dev == ip6ip6_fb_tnl_dev)
                                break;
-                       }
-               } else {
-                       t = netdev_priv(dev);
+                       dev = t->dev;
                }
-               err = unregister_netdevice(t->dev);
+               err = unregister_netdevice(dev);
                break;
        default:
                err = -EINVAL;