From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 1/5] netfilter: nat: don't register device notifier twice
Date: Mon, 11 Mar 2019 23:50:31 +0100 [thread overview]
Message-ID: <20190311225035.21250-2-pablo@netfilter.org> (raw)
In-Reply-To: <20190311225035.21250-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
Otherwise, we get notifier list corruption.
This is the most simple fix: remove the device notifier call chain
from the ipv6 masquerade register function and handle it only
in the ipv4 version.
The better fix is merge
nf_nat_masquerade_ipv4/6_(un)register_notifier
into a single
nf_nat_masquerade_(un)register_notifiers
but to do this its needed to first merge the two masquerade modules
into a single xt_MASQUERADE.
Furthermore, we need to use different refcounts for ipv4/ipv6
until we can merge MASQUERADE.
Fixes: d1aca8ab3104a ("netfilter: nat: merge ipv4 and ipv6 masquerade functionality")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_nat_masquerade.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/net/netfilter/nf_nat_masquerade.c b/net/netfilter/nf_nat_masquerade.c
index 86fa4dcc63c5..d85c4d902e7b 100644
--- a/net/netfilter/nf_nat_masquerade.c
+++ b/net/netfilter/nf_nat_masquerade.c
@@ -11,7 +11,8 @@
#include <net/netfilter/ipv6/nf_nat_masquerade.h>
static DEFINE_MUTEX(masq_mutex);
-static unsigned int masq_refcnt __read_mostly;
+static unsigned int masq_refcnt4 __read_mostly;
+static unsigned int masq_refcnt6 __read_mostly;
unsigned int
nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum,
@@ -141,8 +142,13 @@ int nf_nat_masquerade_ipv4_register_notifier(void)
int ret = 0;
mutex_lock(&masq_mutex);
+ if (WARN_ON_ONCE(masq_refcnt4 == UINT_MAX)) {
+ ret = -EOVERFLOW;
+ goto out_unlock;
+ }
+
/* check if the notifier was already set */
- if (++masq_refcnt > 1)
+ if (++masq_refcnt4 > 1)
goto out_unlock;
/* Register for device down reports */
@@ -160,7 +166,7 @@ int nf_nat_masquerade_ipv4_register_notifier(void)
err_unregister:
unregister_netdevice_notifier(&masq_dev_notifier);
err_dec:
- masq_refcnt--;
+ masq_refcnt4--;
out_unlock:
mutex_unlock(&masq_mutex);
return ret;
@@ -171,7 +177,7 @@ void nf_nat_masquerade_ipv4_unregister_notifier(void)
{
mutex_lock(&masq_mutex);
/* check if the notifier still has clients */
- if (--masq_refcnt > 0)
+ if (--masq_refcnt4 > 0)
goto out_unlock;
unregister_netdevice_notifier(&masq_dev_notifier);
@@ -321,25 +327,23 @@ int nf_nat_masquerade_ipv6_register_notifier(void)
int ret = 0;
mutex_lock(&masq_mutex);
- /* check if the notifier is already set */
- if (++masq_refcnt > 1)
+ if (WARN_ON_ONCE(masq_refcnt6 == UINT_MAX)) {
+ ret = -EOVERFLOW;
goto out_unlock;
+ }
- ret = register_netdevice_notifier(&masq_dev_notifier);
- if (ret)
- goto err_dec;
+ /* check if the notifier is already set */
+ if (++masq_refcnt6 > 1)
+ goto out_unlock;
ret = register_inet6addr_notifier(&masq_inet6_notifier);
if (ret)
- goto err_unregister;
+ goto err_dec;
mutex_unlock(&masq_mutex);
return ret;
-
-err_unregister:
- unregister_netdevice_notifier(&masq_dev_notifier);
err_dec:
- masq_refcnt--;
+ masq_refcnt6--;
out_unlock:
mutex_unlock(&masq_mutex);
return ret;
@@ -350,11 +354,10 @@ void nf_nat_masquerade_ipv6_unregister_notifier(void)
{
mutex_lock(&masq_mutex);
/* check if the notifier still has clients */
- if (--masq_refcnt > 0)
+ if (--masq_refcnt6 > 0)
goto out_unlock;
unregister_inet6addr_notifier(&masq_inet6_notifier);
- unregister_netdevice_notifier(&masq_dev_notifier);
out_unlock:
mutex_unlock(&masq_mutex);
}
--
2.11.0
next prev parent reply other threads:[~2019-03-11 22:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 22:50 [PATCH 0/5] Netfilter fixes for net Pablo Neira Ayuso
2019-03-11 22:50 ` Pablo Neira Ayuso [this message]
2019-03-11 22:50 ` [PATCH 2/5] netfilter: nf_tables: fix set double-free in abort path Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 3/5] netfilter: nf_tables: bogus EBUSY when deleting set after flush Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 4/5] netfilter: nf_tables: use-after-free in dynamic operations Pablo Neira Ayuso
2019-03-11 22:50 ` [PATCH 5/5] netfilter: nf_tables: return immediately on empty commit Pablo Neira Ayuso
2019-03-11 23:14 ` [PATCH 0/5] Netfilter fixes for net David Miller
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