<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/ipv4/tcp.c, branch v5.6</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>tcp: repair: fix TCP_QUEUE_SEQ implementation</title>
<updated>2020-03-23T20:02:01+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-03-19T02:21:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6cd6cbf593bfa3ae6fc3ed34ac21da4d35045425'/>
<id>6cd6cbf593bfa3ae6fc3ed34ac21da4d35045425</id>
<content type='text'>
When application uses TCP_QUEUE_SEQ socket option to
change tp-&gt;rcv_next, we must also update tp-&gt;copied_seq.

Otherwise, stuff relying on tcp_inq() being precise can
eventually be confused.

For example, tcp_zerocopy_receive() might crash because
it does not expect tcp_recv_skb() to return NULL.

We could add tests in various places to fix the issue,
or simply make sure tcp_inq() wont return a random value,
and leave fast path as it is.

Note that this fixes ioctl(fd, SIOCINQ, &amp;val) at the same
time.

Fixes: ee9952831cfd ("tcp: Initial repair mode")
Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When application uses TCP_QUEUE_SEQ socket option to
change tp-&gt;rcv_next, we must also update tp-&gt;copied_seq.

Otherwise, stuff relying on tcp_inq() being precise can
eventually be confused.

For example, tcp_zerocopy_receive() might crash because
it does not expect tcp_recv_skb() to return NULL.

We could add tests in various places to fix the issue,
or simply make sure tcp_inq() wont return a random value,
and leave fast path as it is.

Note that this fixes ioctl(fd, SIOCINQ, &amp;val) at the same
time.

Fixes: ee9952831cfd ("tcp: Initial repair mode")
Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: clear tp-&gt;segs_{in|out} in tcp_disconnect()</title>
<updated>2020-02-01T06:12:37+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-31T18:44:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=784f8344de750a41344f4bbbebb8507a730fc99c'/>
<id>784f8344de750a41344f4bbbebb8507a730fc99c</id>
<content type='text'>
tp-&gt;segs_in and tp-&gt;segs_out need to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: 2efd055c53c0 ("tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Marcelo Ricardo Leitner &lt;mleitner@redhat.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
tp-&gt;segs_in and tp-&gt;segs_out need to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: 2efd055c53c0 ("tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Marcelo Ricardo Leitner &lt;mleitner@redhat.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: clear tp-&gt;data_segs{in|out} in tcp_disconnect()</title>
<updated>2020-02-01T06:12:22+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-31T18:32:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=db7ffee6f3eb3683cdcaeddecc0a630a14546fe3'/>
<id>db7ffee6f3eb3683cdcaeddecc0a630a14546fe3</id>
<content type='text'>
tp-&gt;data_segs_in and tp-&gt;data_segs_out need to be cleared
in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: a44d6eacdaf5 ("tcp: Add RFC4898 tcpEStatsPerfDataSegsOut/In")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
tp-&gt;data_segs_in and tp-&gt;data_segs_out need to be cleared
in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: a44d6eacdaf5 ("tcp: Add RFC4898 tcpEStatsPerfDataSegsOut/In")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Martin KaFai Lau &lt;kafai@fb.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: clear tp-&gt;delivered in tcp_disconnect()</title>
<updated>2020-02-01T06:12:18+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-31T18:22:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2fbdd56251b5c62f96589f39eded277260de7267'/>
<id>2fbdd56251b5c62f96589f39eded277260de7267</id>
<content type='text'>
tp-&gt;delivered needs to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: ddf1af6fa00e ("tcp: new delivery accounting")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Soheil Hassas Yeganeh &lt;soheil@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
tp-&gt;delivered needs to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: ddf1af6fa00e ("tcp: new delivery accounting")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Soheil Hassas Yeganeh &lt;soheil@google.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: clear tp-&gt;total_retrans in tcp_disconnect()</title>
<updated>2020-02-01T06:11:35+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-31T17:14:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c13c48c00a6bc1febc73902505bdec0967bd7095'/>
<id>c13c48c00a6bc1febc73902505bdec0967bd7095</id>
<content type='text'>
total_retrans needs to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: SeongJae Park &lt;sjpark@amazon.de&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
total_retrans needs to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: SeongJae Park &lt;sjpark@amazon.de&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: export count for rehash attempts</title>
<updated>2020-01-26T14:28:47+00:00</updated>
<author>
<name>Abdul Kabbani</name>
<email>akabbani@google.com</email>
</author>
<published>2020-01-24T21:34:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=32efcc06d2a15fa87585614d12d6c2308cc2d3f3'/>
<id>32efcc06d2a15fa87585614d12d6c2308cc2d3f3</id>
<content type='text'>
Using IPv6 flow-label to swiftly route around avoid congested or
disconnected network path can greatly improve TCP reliability.

This patch adds SNMP counters and a OPT_STATS counter to track both
host-level and connection-level statistics. Network administrators
can use these counters to evaluate the impact of this new ability better.

Export count for rehash attempts to
1) two SNMP counters: TcpTimeoutRehash (rehash due to timeouts),
   and TcpDuplicateDataRehash (rehash due to receiving duplicate
   packets)
2) Timestamping API SOF_TIMESTAMPING_OPT_STATS.

Signed-off-by: Abdul Kabbani &lt;akabbani@google.com&gt;
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Kevin(Yudong) Yang &lt;yyd@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Using IPv6 flow-label to swiftly route around avoid congested or
disconnected network path can greatly improve TCP reliability.

This patch adds SNMP counters and a OPT_STATS counter to track both
host-level and connection-level statistics. Network administrators
can use these counters to evaluate the impact of this new ability better.

Export count for rehash attempts to
1) two SNMP counters: TcpTimeoutRehash (rehash due to timeouts),
   and TcpDuplicateDataRehash (rehash due to receiving duplicate
   packets)
2) Timestamping API SOF_TIMESTAMPING_OPT_STATS.

Signed-off-by: Abdul Kabbani &lt;akabbani@google.com&gt;
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Kevin(Yudong) Yang &lt;yyd@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2020-01-26T09:40:21+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2020-01-26T09:40:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4d8773b68e83558025303f266070b31bc4101e73'/>
<id>4d8773b68e83558025303f266070b31bc4101e73</id>
<content type='text'>
Minor conflict in mlx5 because changes happened to code that has
moved meanwhile.

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Minor conflict in mlx5 because changes happened to code that has
moved meanwhile.

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mptcp: Add MPTCP socket stubs</title>
<updated>2020-01-24T12:44:07+00:00</updated>
<author>
<name>Mat Martineau</name>
<email>mathew.j.martineau@linux.intel.com</email>
</author>
<published>2020-01-22T00:56:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f870fa0b5768842cb4690c1c11f19f28b731ae6d'/>
<id>f870fa0b5768842cb4690c1c11f19f28b731ae6d</id>
<content type='text'>
Implements the infrastructure for MPTCP sockets.

MPTCP sockets open one in-kernel TCP socket per subflow. These subflow
sockets are only managed by the MPTCP socket that owns them and are not
visible from userspace. This commit allows a userspace program to open
an MPTCP socket with:

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);

The resulting socket is simply a wrapper around a single regular TCP
socket, without any of the MPTCP protocol implemented over the wire.

Co-developed-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Co-developed-by: Peter Krystad &lt;peter.krystad@linux.intel.com&gt;
Signed-off-by: Peter Krystad &lt;peter.krystad@linux.intel.com&gt;
Co-developed-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Co-developed-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Mat Martineau &lt;mathew.j.martineau@linux.intel.com&gt;
Signed-off-by: Christoph Paasch &lt;cpaasch@apple.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Implements the infrastructure for MPTCP sockets.

MPTCP sockets open one in-kernel TCP socket per subflow. These subflow
sockets are only managed by the MPTCP socket that owns them and are not
visible from userspace. This commit allows a userspace program to open
an MPTCP socket with:

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);

The resulting socket is simply a wrapper around a single regular TCP
socket, without any of the MPTCP protocol implemented over the wire.

Co-developed-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Co-developed-by: Peter Krystad &lt;peter.krystad@linux.intel.com&gt;
Signed-off-by: Peter Krystad &lt;peter.krystad@linux.intel.com&gt;
Co-developed-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Co-developed-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Mat Martineau &lt;mathew.j.martineau@linux.intel.com&gt;
Signed-off-by: Christoph Paasch &lt;cpaasch@apple.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: do not leave dangling pointers in tp-&gt;highest_sack</title>
<updated>2020-01-24T08:06:48+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2020-01-23T05:03:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2bec445f9bf35e52e395b971df48d3e1e5dc704a'/>
<id>2bec445f9bf35e52e395b971df48d3e1e5dc704a</id>
<content type='text'>
Latest commit 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
apparently allowed syzbot to trigger various crashes in TCP stack [1]

I believe this commit only made things easier for syzbot to find
its way into triggering use-after-frees. But really the bugs
could lead to bad TCP behavior or even plain crashes even for
non malicious peers.

I have audited all calls to tcp_rtx_queue_unlink() and
tcp_rtx_queue_unlink_and_free() and made sure tp-&gt;highest_sack would be updated
if we are removing from rtx queue the skb that tp-&gt;highest_sack points to.

These updates were missing in three locations :

1) tcp_clean_rtx_queue() [This one seems quite serious,
                          I have no idea why this was not caught earlier]

2) tcp_rtx_queue_purge() [Probably not a big deal for normal operations]

3) tcp_send_synack()     [Probably not a big deal for normal operations]

[1]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
BUG: KASAN: use-after-free in tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
Read of size 4 at addr ffff8880a488d068 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134
 tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
 tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
 tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
 tcp_try_undo_partial net/ipv4/tcp_input.c:2730 [inline]
 tcp_fastretrans_alert+0xf74/0x23f0 net/ipv4/tcp_input.c:2847
 tcp_ack+0x2577/0x5bf0 net/ipv4/tcp_input.c:3710
 tcp_rcv_established+0x6dd/0x1e90 net/ipv4/tcp_input.c:5706
 tcp_v4_do_rcv+0x619/0x8d0 net/ipv4/tcp_ipv4.c:1619
 tcp_v4_rcv+0x307f/0x3b40 net/ipv4/tcp_ipv4.c:2001
 ip_protocol_deliver_rcu+0x5a/0x880 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x23b/0x380 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x1db/0x2f0 net/ipv4/ip_input.c:428
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:538
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5148
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5262
 process_backlog+0x206/0x750 net/core/dev.c:6093
 napi_poll net/core/dev.c:6530 [inline]
 net_rx_action+0x508/0x1120 net/core/dev.c:6598
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 10091:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slab.c:3263 [inline]
 kmem_cache_alloc_node+0x138/0x740 mm/slab.c:3575
 __alloc_skb+0xd5/0x5e0 net/core/skbuff.c:198
 alloc_skb_fclone include/linux/skbuff.h:1099 [inline]
 sk_stream_alloc_skb net/ipv4/tcp.c:875 [inline]
 sk_stream_alloc_skb+0x113/0xc90 net/ipv4/tcp.c:852
 tcp_sendmsg_locked+0xcf9/0x3470 net/ipv4/tcp.c:1282
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1432
 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 __sys_sendto+0x262/0x380 net/socket.c:1998
 __do_sys_sendto net/socket.c:2010 [inline]
 __se_sys_sendto net/socket.c:2006 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:2006
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10095:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3694
 kfree_skbmem+0x178/0x1c0 net/core/skbuff.c:645
 __kfree_skb+0x1e/0x30 net/core/skbuff.c:681
 sk_eat_skb include/net/sock.h:2453 [inline]
 tcp_recvmsg+0x1252/0x2930 net/ipv4/tcp.c:2166
 inet_recvmsg+0x136/0x610 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_recvmsg+0xce/0x110 net/socket.c:900
 __sys_recvfrom+0x1ff/0x350 net/socket.c:2055
 __do_sys_recvfrom net/socket.c:2073 [inline]
 __se_sys_recvfrom net/socket.c:2069 [inline]
 __x64_sys_recvfrom+0xe1/0x1a0 net/socket.c:2069
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a488d040
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8880a488d040, ffff8880a488d208)
The buggy address belongs to the page:
page:ffffea0002922340 refcount:1 mapcount:0 mapping:ffff88821b057000 index:0x0
raw: 00fffe0000000200 ffffea00022a5788 ffffea0002624a48 ffff88821b057000
raw: 0000000000000000 ffff8880a488d040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a488cf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a488cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
&gt;ffff8880a488d000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880a488d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a488d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
Fixes: 50895b9de1d3 ("tcp: highest_sack fix")
Fixes: 737ff314563c ("tcp: use sequence distance to detect reordering")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Cambda Zhu &lt;cambda@linux.alibaba.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Latest commit 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
apparently allowed syzbot to trigger various crashes in TCP stack [1]

I believe this commit only made things easier for syzbot to find
its way into triggering use-after-frees. But really the bugs
could lead to bad TCP behavior or even plain crashes even for
non malicious peers.

I have audited all calls to tcp_rtx_queue_unlink() and
tcp_rtx_queue_unlink_and_free() and made sure tp-&gt;highest_sack would be updated
if we are removing from rtx queue the skb that tp-&gt;highest_sack points to.

These updates were missing in three locations :

1) tcp_clean_rtx_queue() [This one seems quite serious,
                          I have no idea why this was not caught earlier]

2) tcp_rtx_queue_purge() [Probably not a big deal for normal operations]

3) tcp_send_synack()     [Probably not a big deal for normal operations]

[1]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
BUG: KASAN: use-after-free in tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
BUG: KASAN: use-after-free in tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
Read of size 4 at addr ffff8880a488d068 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.5.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134
 tcp_highest_sack_seq include/net/tcp.h:1864 [inline]
 tcp_highest_sack_seq include/net/tcp.h:1856 [inline]
 tcp_check_sack_reordering+0x33c/0x3a0 net/ipv4/tcp_input.c:891
 tcp_try_undo_partial net/ipv4/tcp_input.c:2730 [inline]
 tcp_fastretrans_alert+0xf74/0x23f0 net/ipv4/tcp_input.c:2847
 tcp_ack+0x2577/0x5bf0 net/ipv4/tcp_input.c:3710
 tcp_rcv_established+0x6dd/0x1e90 net/ipv4/tcp_input.c:5706
 tcp_v4_do_rcv+0x619/0x8d0 net/ipv4/tcp_ipv4.c:1619
 tcp_v4_rcv+0x307f/0x3b40 net/ipv4/tcp_ipv4.c:2001
 ip_protocol_deliver_rcu+0x5a/0x880 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x23b/0x380 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x1db/0x2f0 net/ipv4/ip_input.c:428
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:538
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5148
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5262
 process_backlog+0x206/0x750 net/core/dev.c:6093
 napi_poll net/core/dev.c:6530 [inline]
 net_rx_action+0x508/0x1120 net/core/dev.c:6598
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 10091:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slab.c:3263 [inline]
 kmem_cache_alloc_node+0x138/0x740 mm/slab.c:3575
 __alloc_skb+0xd5/0x5e0 net/core/skbuff.c:198
 alloc_skb_fclone include/linux/skbuff.h:1099 [inline]
 sk_stream_alloc_skb net/ipv4/tcp.c:875 [inline]
 sk_stream_alloc_skb+0x113/0xc90 net/ipv4/tcp.c:852
 tcp_sendmsg_locked+0xcf9/0x3470 net/ipv4/tcp.c:1282
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1432
 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:672
 __sys_sendto+0x262/0x380 net/socket.c:1998
 __do_sys_sendto net/socket.c:2010 [inline]
 __se_sys_sendto net/socket.c:2006 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:2006
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10095:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3694
 kfree_skbmem+0x178/0x1c0 net/core/skbuff.c:645
 __kfree_skb+0x1e/0x30 net/core/skbuff.c:681
 sk_eat_skb include/net/sock.h:2453 [inline]
 tcp_recvmsg+0x1252/0x2930 net/ipv4/tcp.c:2166
 inet_recvmsg+0x136/0x610 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_recvmsg+0xce/0x110 net/socket.c:900
 __sys_recvfrom+0x1ff/0x350 net/socket.c:2055
 __do_sys_recvfrom net/socket.c:2073 [inline]
 __se_sys_recvfrom net/socket.c:2069 [inline]
 __x64_sys_recvfrom+0xe1/0x1a0 net/socket.c:2069
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a488d040
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8880a488d040, ffff8880a488d208)
The buggy address belongs to the page:
page:ffffea0002922340 refcount:1 mapcount:0 mapping:ffff88821b057000 index:0x0
raw: 00fffe0000000200 ffffea00022a5788 ffffea0002624a48 ffff88821b057000
raw: 0000000000000000 ffff8880a488d040 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a488cf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a488cf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
&gt;ffff8880a488d000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                          ^
 ffff8880a488d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a488d100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 853697504de0 ("tcp: Fix highest_sack and highest_sack_seq")
Fixes: 50895b9de1d3 ("tcp: highest_sack fix")
Fixes: 737ff314563c ("tcp: use sequence distance to detect reordering")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Cambda Zhu &lt;cambda@linux.alibaba.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Cc: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Acked-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: remove redundant assigment to snd_cwnd</title>
<updated>2020-01-21T09:52:29+00:00</updated>
<author>
<name>Theodore Dubois</name>
<email>tblodt@icloud.com</email>
</author>
<published>2020-01-20T22:10:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bfe02b9f9476bc8784ebb0f78fa244ad15bb15ea'/>
<id>bfe02b9f9476bc8784ebb0f78fa244ad15bb15ea</id>
<content type='text'>
Not sure how this got in here. git blame says the second assignment was
added in 3a9a57f6, but that commit also removed the first assignment.

Signed-off-by: Theodore Dubois &lt;tblodt@icloud.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Not sure how this got in here. git blame says the second assignment was
added in 3a9a57f6, but that commit also removed the first assignment.

Signed-off-by: Theodore Dubois &lt;tblodt@icloud.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
