<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/bridge, branch v4.4.185</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>bridge: Fix error path for kobject_init_and_add()</title>
<updated>2019-05-16T17:45:17+00:00</updated>
<author>
<name>Tobin C. Harding</name>
<email>tobin@kernel.org</email>
</author>
<published>2019-05-10T02:52:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=24d2a86b89683e99745a4df0c0edce5d28be519e'/>
<id>24d2a86b89683e99745a4df0c0edce5d28be519e</id>
<content type='text'>
[ Upstream commit bdfad5aec1392b93495b77b864d58d7f101dc1c1 ]

Currently error return from kobject_init_and_add() is not followed by a
call to kobject_put().  This means there is a memory leak.  We currently
set p to NULL so that kfree() may be called on it as a noop, the code is
arguably clearer if we move the kfree() up closer to where it is
called (instead of after goto jump).

Remove a goto label 'err1' and jump to call to kobject_put() in error
return from kobject_init_and_add() fixing the memory leak.  Re-name goto
label 'put_back' to 'err1' now that we don't use err1, following current
nomenclature (err1, err2 ...).  Move call to kfree out of the error
code at bottom of function up to closer to where memory was allocated.
Add comment to clarify call to kfree().

Signed-off-by: Tobin C. Harding &lt;tobin@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bdfad5aec1392b93495b77b864d58d7f101dc1c1 ]

Currently error return from kobject_init_and_add() is not followed by a
call to kobject_put().  This means there is a memory leak.  We currently
set p to NULL so that kfree() may be called on it as a noop, the code is
arguably clearer if we move the kfree() up closer to where it is
called (instead of after goto jump).

Remove a goto label 'err1' and jump to call to kobject_put() in error
return from kobject_init_and_add() fixing the memory leak.  Re-name goto
label 'put_back' to 'err1' now that we don't use err1, following current
nomenclature (err1, err2 ...).  Move call to kfree out of the error
code at bottom of function up to closer to where memory was allocated.
Add comment to clarify call to kfree().

Signed-off-by: Tobin C. Harding &lt;tobin@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: bridge: set skb transport_header before entering NF_INET_PRE_ROUTING</title>
<updated>2019-05-16T17:44:57+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2019-03-13T08:33:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6e361910119b67d3281c0b2d00f72e43f08ac100'/>
<id>6e361910119b67d3281c0b2d00f72e43f08ac100</id>
<content type='text'>
[ Upstream commit e166e4fdaced850bee3d5ee12a5740258fb30587 ]

Since Commit 21d1196a35f5 ("ipv4: set transport header earlier"),
skb-&gt;transport_header has been always set before entering INET
netfilter. This patch is to set skb-&gt;transport_header for bridge
before entering INET netfilter by bridge-nf-call-iptables.

It also fixes an issue that sctp_error() couldn't compute a right
csum due to unset skb-&gt;transport_header.

Fixes: e6d8b64b34aa ("net: sctp: fix and consolidate SCTP checksumming code")
Reported-by: Li Shuang &lt;shuali@redhat.com&gt;
Suggested-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Acked-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin (Microsoft) &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e166e4fdaced850bee3d5ee12a5740258fb30587 ]

Since Commit 21d1196a35f5 ("ipv4: set transport header earlier"),
skb-&gt;transport_header has been always set before entering INET
netfilter. This patch is to set skb-&gt;transport_header for bridge
before entering INET netfilter by bridge-nf-call-iptables.

It also fixes an issue that sctp_error() couldn't compute a right
csum due to unset skb-&gt;transport_header.

Fixes: e6d8b64b34aa ("net: sctp: fix and consolidate SCTP checksumming code")
Reported-by: Li Shuang &lt;shuali@redhat.com&gt;
Suggested-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Neil Horman &lt;nhorman@tuxdriver.com&gt;
Acked-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin (Microsoft) &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: ebtables: CONFIG_COMPAT: drop a bogus WARN_ON</title>
<updated>2019-05-16T17:44:51+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-04-14T22:43:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cafee685fb481f2570267e9c240835831524b4ad'/>
<id>cafee685fb481f2570267e9c240835831524b4ad</id>
<content type='text'>
commit 7caa56f006e9d712b44f27b32520c66420d5cbc6 upstream.

It means userspace gave us a ruleset where there is some other
data after the ebtables target but before the beginning of the next rule.

Fixes: 81e675c227ec ("netfilter: ebtables: add CONFIG_COMPAT support")
Reported-by: syzbot+659574e7bcc7f7eb4df7@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7caa56f006e9d712b44f27b32520c66420d5cbc6 upstream.

It means userspace gave us a ruleset where there is some other
data after the ebtables target but before the beginning of the next rule.

Fixes: 81e675c227ec ("netfilter: ebtables: add CONFIG_COMPAT support")
Reported-by: syzbot+659574e7bcc7f7eb4df7@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: bridge: multicast: use rcu to access port list from br_multicast_start_querier</title>
<updated>2019-04-27T07:34:00+00:00</updated>
<author>
<name>Nikolay Aleksandrov</name>
<email>nikolay@cumulusnetworks.com</email>
</author>
<published>2019-04-11T12:08:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dc20066a631c4cba287cd3a9920718a6e6658a76'/>
<id>dc20066a631c4cba287cd3a9920718a6e6658a76</id>
<content type='text'>
[ Upstream commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 ]

br_multicast_start_querier() walks over the port list but it can be
called from a timer with only multicast_lock held which doesn't protect
the port list, so use RCU to walk over it.

Fixes: c83b8fab06fc ("bridge: Restart queries when last querier expires")
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 ]

br_multicast_start_querier() walks over the port list but it can be
called from a timer with only multicast_lock held which doesn't protect
the port list, so use RCU to walk over it.

Fixes: c83b8fab06fc ("bridge: Restart queries when last querier expires")
Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: physdev: relax br_netfilter dependency</title>
<updated>2019-04-27T07:33:53+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2019-01-11T13:46:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=421d2aae103cc215cc8167c00e842441d2b06fce'/>
<id>421d2aae103cc215cc8167c00e842441d2b06fce</id>
<content type='text'>
[ Upstream commit 8e2f311a68494a6677c1724bdcb10bada21af37c ]

Following command:
  iptables -D FORWARD -m physdev ...
causes connectivity loss in some setups.

Reason is that iptables userspace will probe kernel for the module revision
of the physdev patch, and physdev has an artificial dependency on
br_netfilter (xt_physdev use makes no sense unless a br_netfilter module
is loaded).

This causes the "phydev" module to be loaded, which in turn enables the
"call-iptables" infrastructure.

bridged packets might then get dropped by the iptables ruleset.

The better fix would be to change the "call-iptables" defaults to 0 and
enforce explicit setting to 1, but that breaks backwards compatibility.

This does the next best thing: add a request_module call to checkentry.
This was a stray '-D ... -m physdev' won't activate br_netfilter
anymore.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8e2f311a68494a6677c1724bdcb10bada21af37c ]

Following command:
  iptables -D FORWARD -m physdev ...
causes connectivity loss in some setups.

Reason is that iptables userspace will probe kernel for the module revision
of the physdev patch, and physdev has an artificial dependency on
br_netfilter (xt_physdev use makes no sense unless a br_netfilter module
is loaded).

This causes the "phydev" module to be loaded, which in turn enables the
"call-iptables" infrastructure.

bridged packets might then get dropped by the iptables ruleset.

The better fix would be to change the "call-iptables" defaults to 0 and
enforce explicit setting to 1, but that breaks backwards compatibility.

This does the next best thing: add a request_module call to checkentry.
This was a stray '-D ... -m physdev' won't activate br_netfilter
anymore.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: x_tables: enforce nul-terminated table name from getsockopt GET_ENTRIES</title>
<updated>2019-03-23T07:44:29+00:00</updated>
<author>
<name>Pablo Neira Ayuso</name>
<email>pablo@netfilter.org</email>
</author>
<published>2016-03-24T20:29:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9a07167f70a717a5171944195553c8fed7294d6b'/>
<id>9a07167f70a717a5171944195553c8fed7294d6b</id>
<content type='text'>
commit b301f2538759933cf9ff1f7c4f968da72e3f0757 upstream.

Make sure the table names via getsockopt GET_ENTRIES is nul-terminated
in ebtables and all the x_tables variants and their respective compat
code. Uncovered by KASAN.

Reported-by: Baozeng Ding &lt;sploving1@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Cc: Zubin Mithra &lt;zsm@chromium.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b301f2538759933cf9ff1f7c4f968da72e3f0757 upstream.

Make sure the table names via getsockopt GET_ENTRIES is nul-terminated
in ebtables and all the x_tables variants and their respective compat
code. Uncovered by KASAN.

Reported-by: Baozeng Ding &lt;sploving1@gmail.com&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Cc: Zubin Mithra &lt;zsm@chromium.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "bridge: do not add port to router list when receives query with source 0.0.0.0"</title>
<updated>2019-03-23T07:44:18+00:00</updated>
<author>
<name>Hangbin Liu</name>
<email>liuhangbin@gmail.com</email>
</author>
<published>2019-02-22T13:22:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0effb9fb3dfeac514d8ce8a2ba3da970793711ba'/>
<id>0effb9fb3dfeac514d8ce8a2ba3da970793711ba</id>
<content type='text'>
commit 278e2148c07559dd4ad8602f22366d61eb2ee7b7 upstream.

This reverts commit 5a2de63fd1a5 ("bridge: do not add port to router list
when receives query with source 0.0.0.0") and commit 0fe5119e267f ("net:
bridge: remove ipv6 zero address check in mcast queries")

The reason is RFC 4541 is not a standard but suggestive. Currently we
will elect 0.0.0.0 as Querier if there is no ip address configured on
bridge. If we do not add the port which recives query with source
0.0.0.0 to router list, the IGMP reports will not be about to forward
to Querier, IGMP data will also not be able to forward to dest.

As Nikolay suggested, revert this change first and add a boolopt api
to disable none-zero election in future if needed.

Reported-by: Linus Lüssing &lt;linus.luessing@c0d3.blue&gt;
Reported-by: Sebastian Gottschall &lt;s.gottschall@newmedia-net.de&gt;
Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when receives query with source 0.0.0.0")
Fixes: 0fe5119e267f ("net: bridge: remove ipv6 zero address check in mcast queries")
Signed-off-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Acked-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 278e2148c07559dd4ad8602f22366d61eb2ee7b7 upstream.

This reverts commit 5a2de63fd1a5 ("bridge: do not add port to router list
when receives query with source 0.0.0.0") and commit 0fe5119e267f ("net:
bridge: remove ipv6 zero address check in mcast queries")

The reason is RFC 4541 is not a standard but suggestive. Currently we
will elect 0.0.0.0 as Querier if there is no ip address configured on
bridge. If we do not add the port which recives query with source
0.0.0.0 to router list, the IGMP reports will not be about to forward
to Querier, IGMP data will also not be able to forward to dest.

As Nikolay suggested, revert this change first and add a boolopt api
to disable none-zero election in future if needed.

Reported-by: Linus Lüssing &lt;linus.luessing@c0d3.blue&gt;
Reported-by: Sebastian Gottschall &lt;s.gottschall@newmedia-net.de&gt;
Fixes: 5a2de63fd1a5 ("bridge: do not add port to router list when receives query with source 0.0.0.0")
Fixes: 0fe5119e267f ("net: bridge: remove ipv6 zero address check in mcast queries")
Signed-off-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Acked-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>net: bridge: Fix ethernet header pointer before check skb forwardable</title>
<updated>2019-02-06T18:43:03+00:00</updated>
<author>
<name>Yunjian Wang</name>
<email>wangyunjian@huawei.com</email>
</author>
<published>2019-01-17T01:46:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e98f787a9975c3fe268f87ac611ac26697df7a20'/>
<id>e98f787a9975c3fe268f87ac611ac26697df7a20</id>
<content type='text'>
[ Upstream commit 28c1382fa28f2e2d9d0d6f25ae879b5af2ecbd03 ]

The skb header should be set to ethernet header before using
is_skb_forwardable. Because the ethernet header length has been
considered in is_skb_forwardable(including dev-&gt;hard_header_len
length).

To reproduce the issue:
1, add 2 ports on linux bridge br using following commands:
$ brctl addbr br
$ brctl addif br eth0
$ brctl addif br eth1
2, the MTU of eth0 and eth1 is 1500
3, send a packet(Data 1480, UDP 8, IP 20, Ethernet 14, VLAN 4)
from eth0 to eth1

So the expect result is packet larger than 1500 cannot pass through
eth0 and eth1. But currently, the packet passes through success, it
means eth1's MTU limit doesn't take effect.

Fixes: f6367b4660dd ("bridge: use is_skb_forwardable in forward path")
Cc: bridge@lists.linux-foundation.org
Cc: Nkolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Cc: Roopa Prabhu &lt;roopa@cumulusnetworks.com&gt;
Cc: Stephen Hemminger &lt;stephen@networkplumber.org&gt;
Signed-off-by: Yunjian Wang &lt;wangyunjian@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 28c1382fa28f2e2d9d0d6f25ae879b5af2ecbd03 ]

The skb header should be set to ethernet header before using
is_skb_forwardable. Because the ethernet header length has been
considered in is_skb_forwardable(including dev-&gt;hard_header_len
length).

To reproduce the issue:
1, add 2 ports on linux bridge br using following commands:
$ brctl addbr br
$ brctl addif br eth0
$ brctl addif br eth1
2, the MTU of eth0 and eth1 is 1500
3, send a packet(Data 1480, UDP 8, IP 20, Ethernet 14, VLAN 4)
from eth0 to eth1

So the expect result is packet larger than 1500 cannot pass through
eth0 and eth1. But currently, the packet passes through success, it
means eth1's MTU limit doesn't take effect.

Fixes: f6367b4660dd ("bridge: use is_skb_forwardable in forward path")
Cc: bridge@lists.linux-foundation.org
Cc: Nkolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Cc: Roopa Prabhu &lt;roopa@cumulusnetworks.com&gt;
Cc: Stephen Hemminger &lt;stephen@networkplumber.org&gt;
Signed-off-by: Yunjian Wang &lt;wangyunjian@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Fix usage of pskb_trim_rcsum</title>
<updated>2019-02-06T18:43:02+00:00</updated>
<author>
<name>Ross Lagerwall</name>
<email>ross.lagerwall@citrix.com</email>
</author>
<published>2019-01-17T15:34:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=52a30a6e141a103601e3039fb9cabb3babf9b2c2'/>
<id>52a30a6e141a103601e3039fb9cabb3babf9b2c2</id>
<content type='text'>
[ Upstream commit 6c57f0458022298e4da1729c67bd33ce41c14e7a ]

In certain cases, pskb_trim_rcsum() may change skb pointers.
Reinitialize header pointers afterwards to avoid potential
use-after-frees. Add a note in the documentation of
pskb_trim_rcsum(). Found by KASAN.

Signed-off-by: Ross Lagerwall &lt;ross.lagerwall@citrix.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 6c57f0458022298e4da1729c67bd33ce41c14e7a ]

In certain cases, pskb_trim_rcsum() may change skb pointers.
Reinitialize header pointers afterwards to avoid potential
use-after-frees. Add a note in the documentation of
pskb_trim_rcsum(). Found by KASAN.

Signed-off-by: Ross Lagerwall &lt;ross.lagerwall@citrix.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: bridge: fix a bug on using a neighbour cache entry without checking its state</title>
<updated>2019-01-26T08:42:49+00:00</updated>
<author>
<name>JianJhen Chen</name>
<email>kchen@synology.com</email>
</author>
<published>2019-01-06T03:28:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=01267fc7a7723d307baf34992657f1010f2ece61'/>
<id>01267fc7a7723d307baf34992657f1010f2ece61</id>
<content type='text'>
[ Upstream commit 4c84edc11b76590859b1e45dd676074c59602dc4 ]

When handling DNAT'ed packets on a bridge device, the neighbour cache entry
from lookup was used without checking its state. It means that a cache entry
in the NUD_STALE state will be used directly instead of entering the NUD_DELAY
state to confirm the reachability of the neighbor.

This problem becomes worse after commit 2724680bceee ("neigh: Keep neighbour
cache entries if number of them is small enough."), since all neighbour cache
entries in the NUD_STALE state will be kept in the neighbour table as long as
the number of cache entries does not exceed the value specified in gc_thresh1.

This commit validates the state of a neighbour cache entry before using
the entry.

Signed-off-by: JianJhen Chen &lt;kchen@synology.com&gt;
Reviewed-by: JinLin Chen &lt;jlchen@synology.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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[ Upstream commit 4c84edc11b76590859b1e45dd676074c59602dc4 ]

When handling DNAT'ed packets on a bridge device, the neighbour cache entry
from lookup was used without checking its state. It means that a cache entry
in the NUD_STALE state will be used directly instead of entering the NUD_DELAY
state to confirm the reachability of the neighbor.

This problem becomes worse after commit 2724680bceee ("neigh: Keep neighbour
cache entries if number of them is small enough."), since all neighbour cache
entries in the NUD_STALE state will be kept in the neighbour table as long as
the number of cache entries does not exceed the value specified in gc_thresh1.

This commit validates the state of a neighbour cache entry before using
the entry.

Signed-off-by: JianJhen Chen &lt;kchen@synology.com&gt;
Reviewed-by: JinLin Chen &lt;jlchen@synology.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
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