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CVE-2016-3135 ipv4: DoS when destroying a network interface (rhbz 1318172 1318270)

This commit is contained in:
Josh Boyer 2016-03-16 08:21:56 -04:00
parent 2e7e84333e
commit f1e9fcace5
2 changed files with 103 additions and 0 deletions
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97
ipv4-Dont-do-expensive-useless-work-during-inetdev-des.patch Normal file
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@ -0,0 +1,97 @@
From fbd40ea0180a2d328c5adc61414dc8bab9335ce2 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Sun, 13 Mar 2016 23:28:00 -0400
Subject: 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>
---
net/ipv4/devinet.c | 4 ++++
net/ipv4/fib_frontend.c | 4 ++++
net/ipv4/netfilter/nf_nat_masquerade_ipv4.c | 12 ++++++++++--
3 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 65e76a4..e333bc8 100644
--- 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 4734475..21add55 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -922,6 +922,9 @@ 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 :-)
*
@@ -997,6 +1000,7 @@ 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 c6eb421..ea91058 100644
--- 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);
}
--
cgit v0.12

6
kernel.spec
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@ -622,6 +622,9 @@ Patch664: netfilter-x_tables-check-for-size-overflow.patch
#CVE-2016-3134 rhbz 1317383 1317384
Patch665: netfilter-x_tables-deal-with-bogus-nextoffset-values.patch
#CVE-2016-3135 rhbz 1318172 1318270
Patch666: ipv4-Dont-do-expensive-useless-work-during-inetdev-des.patch
# END OF PATCH DEFINITIONS
%endif
@ -2143,6 +2146,9 @@ fi
#
#
%changelog
* Wed Mar 16 2016 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2016-3135 ipv4: DoS when destroying a network interface (rhbz 1318172 1318270)
* Mon Mar 14 2016 Justin M. Forbes <jforbes@fedoraproject.org> - 4.5.0-1
- Linux v4.5
- Disable debugging options.