tun: Multicast handling in tun_chr_ioctl() needs proper locking.

Since these operations don't go through the normal device calls, we have to ensure we synchronize with those paths. Noticed by Alan Cox. Signed-off-by: David S. Miller <[email protected]>
ambv · Apr 24, 2008 · 9edb74c · 9edb74c
1 parent 5e659e4
commit 9edb74c
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
@@ -741,15 +741,25 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
 	case SIOCADDMULTI:
 		/** Add the specified group to the character device's multicast filter
 		 * list. */
+		rtnl_lock();
+		netif_tx_lock_bh(tun->dev);
 		add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
+		netif_tx_unlock_bh(tun->dev);
+		rtnl_unlock();
+
 		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. */
+		rtnl_lock();
+		netif_tx_lock_bh(tun->dev);
 		del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
+		netif_tx_unlock_bh(tun->dev);
+		rtnl_unlock();
+
 		DBG(KERN_DEBUG "%s: del multi: %s\n",
 		    tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 		return 0;