<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/tipc, branch v4.19.232</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>tipc: Fix end of loop tests for list_for_each_entry()</title>
<updated>2022-03-02T10:38:11+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2022-02-22T13:43:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=33f724448e055b615301c039df5638cce458d6ac'/>
<id>33f724448e055b615301c039df5638cce458d6ac</id>
<content type='text'>
commit a1f8fec4dac8bc7b172b2bdbd881e015261a6322 upstream.

These tests are supposed to check if the loop exited via a break or not.
However the tests are wrong because if we did not exit via a break then
"p" is not a valid pointer.  In that case, it's the equivalent of
"if (*(u32 *)sr == *last_key) {".  That's going to work most of the time,
but there is a potential for those to be equal.

Fixes: 1593123a6a49 ("tipc: add name table dump to new netlink api")
Fixes: 1a1a143daf84 ("tipc: add publication dump to new netlink api")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.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 a1f8fec4dac8bc7b172b2bdbd881e015261a6322 upstream.

These tests are supposed to check if the loop exited via a break or not.
However the tests are wrong because if we did not exit via a break then
"p" is not a valid pointer.  In that case, it's the equivalent of
"if (*(u32 *)sr == *last_key) {".  That's going to work most of the time,
but there is a potential for those to be equal.

Fixes: 1593123a6a49 ("tipc: add name table dump to new netlink api")
Fixes: 1a1a143daf84 ("tipc: add publication dump to new netlink api")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.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>tipc: rate limit warning for received illegal binding update</title>
<updated>2022-02-16T11:51:46+00:00</updated>
<author>
<name>Jon Maloy</name>
<email>jmaloy@redhat.com</email>
</author>
<published>2022-02-09T03:22:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7b4ba5427c4ea716f73af01b0324209909822485'/>
<id>7b4ba5427c4ea716f73af01b0324209909822485</id>
<content type='text'>
[ Upstream commit c7223d687758462826a20e9735305d55bb874c70 ]

It would be easy to craft a message containing an illegal binding table
update operation. This is handled correctly by the code, but the
corresponding warning printout is not rate limited as is should be.
We fix this now.

Fixes: b97bf3fd8f6a ("[TIPC] Initial merge")
Signed-off-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 c7223d687758462826a20e9735305d55bb874c70 ]

It would be easy to craft a message containing an illegal binding table
update operation. This is handled correctly by the code, but the
corresponding warning printout is not rate limited as is should be.
We fix this now.

Fixes: b97bf3fd8f6a ("[TIPC] Initial merge")
Signed-off-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: improve size validations for received domain records</title>
<updated>2022-02-11T07:44:59+00:00</updated>
<author>
<name>Jon Maloy</name>
<email>jmaloy@redhat.com</email>
</author>
<published>2022-02-05T19:11:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f1af11edd08dd8376f7a84487cbb0ea8203e3a1d'/>
<id>f1af11edd08dd8376f7a84487cbb0ea8203e3a1d</id>
<content type='text'>
commit 9aa422ad326634b76309e8ff342c246800621216 upstream.

The function tipc_mon_rcv() allows a node to receive and process
domain_record structs from peer nodes to track their views of the
network topology.

This patch verifies that the number of members in a received domain
record does not exceed the limit defined by MAX_MON_DOMAIN, something
that may otherwise lead to a stack overflow.

tipc_mon_rcv() is called from the function tipc_link_proto_rcv(), where
we are reading a 32 bit message data length field into a uint16.  To
avert any risk of bit overflow, we add an extra sanity check for this in
that function.  We cannot see that happen with the current code, but
future designers being unaware of this risk, may introduce it by
allowing delivery of very large (&gt; 64k) sk buffers from the bearer
layer.  This potential problem was identified by Eric Dumazet.

This fixes CVE-2022-0435

Reported-by: Samuel Page &lt;samuel.page@appgate.com&gt;
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
Signed-off-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Reviewed-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Reviewed-by: Samuel Page &lt;samuel.page@appgate.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.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 9aa422ad326634b76309e8ff342c246800621216 upstream.

The function tipc_mon_rcv() allows a node to receive and process
domain_record structs from peer nodes to track their views of the
network topology.

This patch verifies that the number of members in a received domain
record does not exceed the limit defined by MAX_MON_DOMAIN, something
that may otherwise lead to a stack overflow.

tipc_mon_rcv() is called from the function tipc_link_proto_rcv(), where
we are reading a 32 bit message data length field into a uint16.  To
avert any risk of bit overflow, we add an extra sanity check for this in
that function.  We cannot see that happen with the current code, but
future designers being unaware of this risk, may introduce it by
allowing delivery of very large (&gt; 64k) sk buffers from the bearer
layer.  This potential problem was identified by Eric Dumazet.

This fixes CVE-2022-0435

Reported-by: Samuel Page &lt;samuel.page@appgate.com&gt;
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
Signed-off-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Reviewed-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Reviewed-by: Samuel Page &lt;samuel.page@appgate.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: increase timeout in tipc_sk_enqueue()</title>
<updated>2021-09-22T09:48:11+00:00</updated>
<author>
<name>Hoang Le</name>
<email>hoang.h.le@dektech.com.au</email>
</author>
<published>2021-09-13T09:28:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=df957462980e7a68ccc389ccee9c2de72e973c43'/>
<id>df957462980e7a68ccc389ccee9c2de72e973c43</id>
<content type='text'>
commit f4bb62e64c88c93060c051195d3bbba804e56945 upstream.

In tipc_sk_enqueue() we use hardcoded 2 jiffies to extract
socket buffer from generic queue to particular socket.
The 2 jiffies is too short in case there are other high priority
tasks get CPU cycles for multiple jiffies update. As result, no
buffer could be enqueued to particular socket.

To solve this, we switch to use constant timeout 20msecs.
Then, the function will be expired between 2 jiffies (CONFIG_100HZ)
and 20 jiffies (CONFIG_1000HZ).

Fixes: c637c1035534 ("tipc: resolve race problem at unicast message reception")
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&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 f4bb62e64c88c93060c051195d3bbba804e56945 upstream.

In tipc_sk_enqueue() we use hardcoded 2 jiffies to extract
socket buffer from generic queue to particular socket.
The 2 jiffies is too short in case there are other high priority
tasks get CPU cycles for multiple jiffies update. As result, no
buffer could be enqueued to particular socket.

To solve this, we switch to use constant timeout 20msecs.
Then, the function will be expired between 2 jiffies (CONFIG_100HZ)
and 20 jiffies (CONFIG_1000HZ).

Fixes: c637c1035534 ("tipc: resolve race problem at unicast message reception")
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&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>tipc: fix an use-after-free issue in tipc_recvmsg</title>
<updated>2021-09-22T09:48:10+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2021-07-23T17:25:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bd02719fe29c9514c7cec70040b71af13e549e11'/>
<id>bd02719fe29c9514c7cec70040b71af13e549e11</id>
<content type='text'>
commit cc19862ffe454a5b632ca202e5a51bfec9f89fd2 upstream.

syzbot reported an use-after-free crash:

  BUG: KASAN: use-after-free in tipc_recvmsg+0xf77/0xf90 net/tipc/socket.c:1979
  Call Trace:
   tipc_recvmsg+0xf77/0xf90 net/tipc/socket.c:1979
   sock_recvmsg_nosec net/socket.c:943 [inline]
   sock_recvmsg net/socket.c:961 [inline]
   sock_recvmsg+0xca/0x110 net/socket.c:957
   tipc_conn_rcv_from_sock+0x162/0x2f0 net/tipc/topsrv.c:398
   tipc_conn_recv_work+0xeb/0x190 net/tipc/topsrv.c:421
   process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
   worker_thread+0x658/0x11f0 kernel/workqueue.c:2422

As Hoang pointed out, it was caused by skb_cb-&gt;bytes_read still accessed
after calling tsk_advance_rx_queue() to free the skb in tipc_recvmsg().

This patch is to fix it by accessing skb_cb-&gt;bytes_read earlier than
calling tsk_advance_rx_queue().

Fixes: f4919ff59c28 ("tipc: keep the skb in rcv queue until the whole data is read")
Reported-by: syzbot+e6741b97d5552f97c24d@syzkaller.appspotmail.com
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.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 cc19862ffe454a5b632ca202e5a51bfec9f89fd2 upstream.

syzbot reported an use-after-free crash:

  BUG: KASAN: use-after-free in tipc_recvmsg+0xf77/0xf90 net/tipc/socket.c:1979
  Call Trace:
   tipc_recvmsg+0xf77/0xf90 net/tipc/socket.c:1979
   sock_recvmsg_nosec net/socket.c:943 [inline]
   sock_recvmsg net/socket.c:961 [inline]
   sock_recvmsg+0xca/0x110 net/socket.c:957
   tipc_conn_rcv_from_sock+0x162/0x2f0 net/tipc/topsrv.c:398
   tipc_conn_recv_work+0xeb/0x190 net/tipc/topsrv.c:421
   process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
   worker_thread+0x658/0x11f0 kernel/workqueue.c:2422

As Hoang pointed out, it was caused by skb_cb-&gt;bytes_read still accessed
after calling tsk_advance_rx_queue() to free the skb in tipc_recvmsg().

This patch is to fix it by accessing skb_cb-&gt;bytes_read earlier than
calling tsk_advance_rx_queue().

Fixes: f4919ff59c28 ("tipc: keep the skb in rcv queue until the whole data is read")
Reported-by: syzbot+e6741b97d5552f97c24d@syzkaller.appspotmail.com
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.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>tipc: keep the skb in rcv queue until the whole data is read</title>
<updated>2021-09-22T09:48:02+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2021-07-16T21:44:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ef306a7dd849d3e623716cb539e56fe4c0f4c64f'/>
<id>ef306a7dd849d3e623716cb539e56fe4c0f4c64f</id>
<content type='text'>
[ Upstream commit f4919ff59c2828064b4156e3c3600a169909bcf4 ]

Currently, when userspace reads a datagram with a buffer that is
smaller than this datagram, the data will be truncated and only
part of it can be received by users. It doesn't seem right that
users don't know the datagram size and have to use a huge buffer
to read it to avoid the truncation.

This patch to fix it by keeping the skb in rcv queue until the
whole data is read by users. Only the last msg of the datagram
will be marked with MSG_EOR, just as TCP/SCTP does.

Note that this will work as above only when MSG_EOR is set in the
flags parameter of recvmsg(), so that it won't break any old user
applications.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 f4919ff59c2828064b4156e3c3600a169909bcf4 ]

Currently, when userspace reads a datagram with a buffer that is
smaller than this datagram, the data will be truncated and only
part of it can be received by users. It doesn't seem right that
users don't know the datagram size and have to use a huge buffer
to read it to avoid the truncation.

This patch to fix it by keeping the skb in rcv queue until the
whole data is read by users. Only the last msg of the datagram
will be marked with MSG_EOR, just as TCP/SCTP does.

Note that this will work as above only when MSG_EOR is set in the
flags parameter of recvmsg(), so that it won't break any old user
applications.

Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: fix sleeping in tipc accept routine</title>
<updated>2021-08-04T10:23:46+00:00</updated>
<author>
<name>Hoang Le</name>
<email>hoang.h.le@dektech.com.au</email>
</author>
<published>2021-07-23T02:25:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=01f178e5f855d38da00f87e9ba51764757e9cee4'/>
<id>01f178e5f855d38da00f87e9ba51764757e9cee4</id>
<content type='text'>
[ Upstream commit d237a7f11719ff9320721be5818352e48071aab6 ]

The release_sock() is blocking function, it would change the state
after sleeping. In order to evaluate the stated condition outside
the socket lock context, switch to use wait_woken() instead.

Fixes: 6398e23cdb1d8 ("tipc: standardize accept routine")
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 d237a7f11719ff9320721be5818352e48071aab6 ]

The release_sock() is blocking function, it would change the state
after sleeping. In order to evaluate the stated condition outside
the socket lock context, switch to use wait_woken() instead.

Fixes: 6398e23cdb1d8 ("tipc: standardize accept routine")
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: fix unique bearer names sanity check</title>
<updated>2021-06-10T11:24:05+00:00</updated>
<author>
<name>Hoang Le</name>
<email>hoang.h.le@dektech.com.au</email>
</author>
<published>2021-04-01T02:30:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a13a42c573a496a05b528ddbe6ea32083f44e9f1'/>
<id>a13a42c573a496a05b528ddbe6ea32083f44e9f1</id>
<content type='text'>
[ Upstream commit f20a46c3044c3f75232b3d0e2d09af9b25efaf45 ]

When enabling a bearer by name, we don't sanity check its name with
higher slot in bearer list. This may have the effect that the name
of an already enabled bearer bypasses the check.

To fix the above issue, we just perform an extra checking with all
existing bearers.

Fixes: cb30a63384bc9 ("tipc: refactor function tipc_enable_bearer()")
Cc: stable@vger.kernel.org
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 f20a46c3044c3f75232b3d0e2d09af9b25efaf45 ]

When enabling a bearer by name, we don't sanity check its name with
higher slot in bearer list. This may have the effect that the name
of an already enabled bearer bypasses the check.

To fix the above issue, we just perform an extra checking with all
existing bearers.

Fixes: cb30a63384bc9 ("tipc: refactor function tipc_enable_bearer()")
Cc: stable@vger.kernel.org
Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: add extack messages for bearer/media failure</title>
<updated>2021-06-10T11:24:05+00:00</updated>
<author>
<name>Hoang Le</name>
<email>hoang.h.le@dektech.com.au</email>
</author>
<published>2021-03-25T01:56:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=65281d6aeca781b024a3cc83df6b55b987877ae8'/>
<id>65281d6aeca781b024a3cc83df6b55b987877ae8</id>
<content type='text'>
[ Upstream commit b83e214b2e04204f1fc674574362061492c37245 ]

Add extack error messages for -EINVAL errors when enabling bearer,
getting/setting properties for a media/bearer

Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 b83e214b2e04204f1fc674574362061492c37245 ]

Add extack error messages for -EINVAL errors when enabling bearer,
getting/setting properties for a media/bearer

Acked-by: Jon Maloy &lt;jmaloy@redhat.com&gt;
Signed-off-by: Hoang Le &lt;hoang.h.le@dektech.com.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tipc: skb_linearize the head skb when reassembling msgs</title>
<updated>2021-06-03T06:38:08+00:00</updated>
<author>
<name>Xin Long</name>
<email>lucien.xin@gmail.com</email>
</author>
<published>2021-05-07T19:57:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4b1761898861117c97066aea6c58f68a7787f0bf'/>
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commit b7df21cf1b79ab7026f545e7bf837bd5750ac026 upstream.

It's not a good idea to append the frag skb to a skb's frag_list if
the frag_list already has skbs from elsewhere, such as this skb was
created by pskb_copy() where the frag_list was cloned (all the skbs
in it were skb_get'ed) and shared by multiple skbs.

However, the new appended frag skb should have been only seen by the
current skb. Otherwise, it will cause use after free crashes as this
appended frag skb are seen by multiple skbs but it only got skb_get
called once.

The same thing happens with a skb updated by pskb_may_pull() with a
skb_cloned skb. Li Shuang has reported quite a few crashes caused
by this when doing testing over macvlan devices:

  [] kernel BUG at net/core/skbuff.c:1970!
  [] Call Trace:
  []  skb_clone+0x4d/0xb0
  []  macvlan_broadcast+0xd8/0x160 [macvlan]
  []  macvlan_process_broadcast+0x148/0x150 [macvlan]
  []  process_one_work+0x1a7/0x360
  []  worker_thread+0x30/0x390

  [] kernel BUG at mm/usercopy.c:102!
  [] Call Trace:
  []  __check_heap_object+0xd3/0x100
  []  __check_object_size+0xff/0x16b
  []  simple_copy_to_iter+0x1c/0x30
  []  __skb_datagram_iter+0x7d/0x310
  []  __skb_datagram_iter+0x2a5/0x310
  []  skb_copy_datagram_iter+0x3b/0x90
  []  tipc_recvmsg+0x14a/0x3a0 [tipc]
  []  ____sys_recvmsg+0x91/0x150
  []  ___sys_recvmsg+0x7b/0xc0

  [] kernel BUG at mm/slub.c:305!
  [] Call Trace:
  []  &lt;IRQ&gt;
  []  kmem_cache_free+0x3ff/0x400
  []  __netif_receive_skb_core+0x12c/0xc40
  []  ? kmem_cache_alloc+0x12e/0x270
  []  netif_receive_skb_internal+0x3d/0xb0
  []  ? get_rx_page_info+0x8e/0xa0 [be2net]
  []  be_poll+0x6ef/0xd00 [be2net]
  []  ? irq_exit+0x4f/0x100
  []  net_rx_action+0x149/0x3b0

  ...

This patch is to fix it by linearizing the head skb if it has frag_list
set in tipc_buf_append(). Note that we choose to do this before calling
skb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can
not just drop the frag_list either as the early time.

Fixes: 45c8b7b175ce ("tipc: allow non-linear first fragment buffer")
Reported-by: Li Shuang &lt;shuali@redhat.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.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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commit b7df21cf1b79ab7026f545e7bf837bd5750ac026 upstream.

It's not a good idea to append the frag skb to a skb's frag_list if
the frag_list already has skbs from elsewhere, such as this skb was
created by pskb_copy() where the frag_list was cloned (all the skbs
in it were skb_get'ed) and shared by multiple skbs.

However, the new appended frag skb should have been only seen by the
current skb. Otherwise, it will cause use after free crashes as this
appended frag skb are seen by multiple skbs but it only got skb_get
called once.

The same thing happens with a skb updated by pskb_may_pull() with a
skb_cloned skb. Li Shuang has reported quite a few crashes caused
by this when doing testing over macvlan devices:

  [] kernel BUG at net/core/skbuff.c:1970!
  [] Call Trace:
  []  skb_clone+0x4d/0xb0
  []  macvlan_broadcast+0xd8/0x160 [macvlan]
  []  macvlan_process_broadcast+0x148/0x150 [macvlan]
  []  process_one_work+0x1a7/0x360
  []  worker_thread+0x30/0x390

  [] kernel BUG at mm/usercopy.c:102!
  [] Call Trace:
  []  __check_heap_object+0xd3/0x100
  []  __check_object_size+0xff/0x16b
  []  simple_copy_to_iter+0x1c/0x30
  []  __skb_datagram_iter+0x7d/0x310
  []  __skb_datagram_iter+0x2a5/0x310
  []  skb_copy_datagram_iter+0x3b/0x90
  []  tipc_recvmsg+0x14a/0x3a0 [tipc]
  []  ____sys_recvmsg+0x91/0x150
  []  ___sys_recvmsg+0x7b/0xc0

  [] kernel BUG at mm/slub.c:305!
  [] Call Trace:
  []  &lt;IRQ&gt;
  []  kmem_cache_free+0x3ff/0x400
  []  __netif_receive_skb_core+0x12c/0xc40
  []  ? kmem_cache_alloc+0x12e/0x270
  []  netif_receive_skb_internal+0x3d/0xb0
  []  ? get_rx_page_info+0x8e/0xa0 [be2net]
  []  be_poll+0x6ef/0xd00 [be2net]
  []  ? irq_exit+0x4f/0x100
  []  net_rx_action+0x149/0x3b0

  ...

This patch is to fix it by linearizing the head skb if it has frag_list
set in tipc_buf_append(). Note that we choose to do this before calling
skb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can
not just drop the frag_list either as the early time.

Fixes: 45c8b7b175ce ("tipc: allow non-linear first fragment buffer")
Reported-by: Li Shuang &lt;shuali@redhat.com&gt;
Signed-off-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Acked-by: Jon Maloy &lt;jmaloy@redhat.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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