tun: send netlink notification when the device is modified

I added dumping of link information about tun devices over netlink in
commit 1ec010e70593 ("tun: export flags, uid, gid, queue information
over netlink"), but didn't add the missing netlink notifications when
the device's exported properties change.

This patch adds notifications when owner/group or flags are modified,
when queues are attached/detached, and when a tun fd is closed.

Reported-by: Thomas Haller <thaller@redhat.com>
Fixes: 1ec010e70593 ("tun: export flags, uid, gid, queue information over netlink")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 2 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c9e68fd76a37..28583aa0c17d 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -743,8 +743,15 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 
 static void tun_detach(struct tun_file *tfile, bool clean)
 {
+        struct tun_struct *tun;
+        struct net_device *dev;
+
         rtnl_lock();
+        tun = rtnl_dereference(tfile->tun);
+        dev = tun ? tun->dev : NULL;
         __tun_detach(tfile, clean);
+        if (dev)
+                netdev_state_change(dev);
         rtnl_unlock();
 }
 
@@ -2562,13 +2569,15 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                         /* One or more queue has already been attached, no need
                          * to initialize the device again.
                          */
+                        netdev_state_change(dev);
                         return 0;
                 }
 
                 tun->flags = (tun->flags & ~TUN_FEATURES) |
                               (ifr->ifr_flags & TUN_FEATURES);
-        }
-        else {
+
+                netdev_state_change(dev);
+        } else {
                 char *name;
                 unsigned long flags = 0;
                 int queues = ifr->ifr_flags & IFF_MULTI_QUEUE ?
@@ -2808,6 +2817,9 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr)
         } else
                 ret = -EINVAL;
 
+        if (ret >= 0)
+                netdev_state_change(tun->dev);
+
 unlock:
         rtnl_unlock();
         return ret;
@@ -2848,6 +2860,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
         unsigned int ifindex;
         int le;
         int ret;
+        bool do_notify = false;
 
         if (cmd == TUNSETIFF || cmd == TUNSETQUEUE ||
             (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) {
@@ -2944,10 +2957,12 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                 if (arg && !(tun->flags & IFF_PERSIST)) {
                         tun->flags |= IFF_PERSIST;
                         __module_get(THIS_MODULE);
+                        do_notify = true;
                 }
                 if (!arg && (tun->flags & IFF_PERSIST)) {
                         tun->flags &= ~IFF_PERSIST;
                         module_put(THIS_MODULE);
+                        do_notify = true;
                 }
 
                 tun_debug(KERN_INFO, tun, "persist %s\n",
@@ -2962,6 +2977,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                         break;
                 }
                 tun->owner = owner;
+                do_notify = true;
                 tun_debug(KERN_INFO, tun, "owner set to %u\n",
                           from_kuid(&init_user_ns, tun->owner));
                 break;
@@ -2974,6 +2990,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                         break;
                 }
                 tun->group = group;
+                do_notify = true;
                 tun_debug(KERN_INFO, tun, "group set to %u\n",
                           from_kgid(&init_user_ns, tun->group));
                 break;
@@ -3133,6 +3150,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
                 break;
         }
 
+        if (do_notify)
+                netdev_state_change(tun->dev);
+
 unlock:
         rtnl_unlock();
         if (tun)