ipv4: Don't do expensive useless work during inetdev destroy.

When an inetdev is destroyed, every address assigned to the interface
is removed.  And in this scenerio we do two pointless things which can
be very expensive if the number of assigned interfaces is large:

1) Address promotion.  We are deleting all addresses, so there is no
   point in doing this.

2) A full nf conntrack table purge for every address.  We only need to
   do this once, as is already caught by the existing
   masq_dev_notifier so masq_inet_event() can skip this.

Reported-by: Solar Designer <solar@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
(cherry picked from commit fbd40ea0180a2d328c5adc61414dc8bab9335ce2)

Orabug: 22933004
CVE: CVE-2016-3156
Signed-off-by: Manjunath Govindashetty <manjunath.govindashetty@oracle.com>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 5055fc683a46756bb9c461746361994311569063..44a684453830796a18c42339dd0e04259ca72ad6 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -334,6 +334,9 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
 
        ASSERT_RTNL();
 
+       if (in_dev->dead)
+               goto no_promotions;
+
        /* 1. Deleting primary ifaddr forces deletion all secondaries
         * unless alias promotion is set
         **/
@@ -380,6 +383,7 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
                        fib_del_ifaddr(ifa, ifa1);
        }
 
+no_promotions:
        /* 2. Unlink it */
 
        *ifap = ifa1->ifa_next;

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 872494e6e6eb7996185a99a8b05915f861a73ec4..87766363d2a41ccf129c2a034a6e8bf8bab66b68 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -876,6 +876,9 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
                subnet = 1;
        }
 
+       if (in_dev->dead)
+               goto no_promotions;
+
        /* Deletion is more complicated than add.
         * We should take care of not to delete too much :-)
         *
@@ -951,6 +954,7 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
                }
        }
 
+no_promotions:
        if (!(ok & BRD_OK))
                fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
        if (subnet && ifa->ifa_prefixlen < 31) {

diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
index c6eb42100e9a7d78a6a5c27434e42e3282b3af74..ea91058b5f6f4245a84179f81a8641756f60efff 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
+++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
@@ -108,10 +108,18 @@ static int masq_inet_event(struct notifier_block *this,
                           unsigned long event,
                           void *ptr)
 {
-       struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
+       struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev;
        struct netdev_notifier_info info;
 
-       netdev_notifier_info_init(&info, dev);
+       /* The masq_dev_notifier will catch the case of the device going
+        * down.  So if the inetdev is dead and being destroyed we have
+        * no work to do.  Otherwise this is an individual address removal
+        * and we have to perform the flush.
+        */
+       if (idev->dead)
+               return NOTIFY_DONE;
+
+       netdev_notifier_info_init(&info, idev->dev);
        return masq_device_event(this, event, &info);
 }