<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/ipv4, branch v6.6.37</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>tcp: fix tcp_rcv_fastopen_synack() to enter TCP_CA_Loss for failed TFO</title>
<updated>2024-07-05T07:33:49+00:00</updated>
<author>
<name>Neal Cardwell</name>
<email>ncardwell@google.com</email>
</author>
<published>2024-06-24T14:43:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b4b26d23a1e2bc188cec8592e111d68d83b9031f'/>
<id>b4b26d23a1e2bc188cec8592e111d68d83b9031f</id>
<content type='text'>
[ Upstream commit 5dfe9d273932c647bdc9d664f939af9a5a398cbc ]

Testing determined that the recent commit 9e046bb111f1 ("tcp: clear
tp-&gt;retrans_stamp in tcp_rcv_fastopen_synack()") has a race, and does
not always ensure retrans_stamp is 0 after a TFO payload retransmit.

If transmit completion for the SYN+data skb happens after the client
TCP stack receives the SYNACK (which sometimes happens), then
retrans_stamp can erroneously remain non-zero for the lifetime of the
connection, causing a premature ETIMEDOUT later.

Testing and tracing showed that the buggy scenario is the following
somewhat tricky sequence:

+ Client attempts a TFO handshake. tcp_send_syn_data() sends SYN + TFO
  cookie + data in a single packet in the syn_data skb. It hands the
  syn_data skb to tcp_transmit_skb(), which makes a clone. Crucially,
  it then reuses the same original (non-clone) syn_data skb,
  transforming it by advancing the seq by one byte and removing the
  FIN bit, and enques the resulting payload-only skb in the
  sk-&gt;tcp_rtx_queue.

+ Client sets retrans_stamp to the start time of the three-way
  handshake.

+ Cookie mismatches or server has TFO disabled, and server only ACKs
  SYN.

+ tcp_ack() sees SYN is acked, tcp_clean_rtx_queue() clears
  retrans_stamp.

+ Since the client SYN was acked but not the payload, the TFO failure
  code path in tcp_rcv_fastopen_synack() tries to retransmit the
  payload skb.  However, in some cases the transmit completion for the
  clone of the syn_data (which had SYN + TFO cookie + data) hasn't
  happened.  In those cases, skb_still_in_host_queue() returns true
  for the retransmitted TFO payload, because the clone of the syn_data
  skb has not had its tx completetion.

+ Because skb_still_in_host_queue() finds skb_fclone_busy() is true,
  it sets the TSQ_THROTTLED bit and the retransmit does not happen in
  the tcp_rcv_fastopen_synack() call chain.

+ The tcp_rcv_fastopen_synack() code next implicitly assumes the
  retransmit process is finished, and sets retrans_stamp to 0 to clear
  it, but this is later overwritten (see below).

+ Later, upon tx completion, tcp_tsq_write() calls
  tcp_xmit_retransmit_queue(), which puts the retransmit in flight and
  sets retrans_stamp to a non-zero value.

+ The client receives an ACK for the retransmitted TFO payload data.

+ Since we're in CA_Open and there are no dupacks/SACKs/DSACKs/ECN to
  make tcp_ack_is_dubious() true and make us call
  tcp_fastretrans_alert() and reach a code path that clears
  retrans_stamp, retrans_stamp stays nonzero.

+ Later, if there is a TLP, RTO, RTO sequence, then the connection
  will suffer an early ETIMEDOUT due to the erroneously ancient
  retrans_stamp.

The fix: this commit refactors the code to have
tcp_rcv_fastopen_synack() retransmit by reusing the relevant parts of
tcp_simple_retransmit() that enter CA_Loss (without changing cwnd) and
call tcp_xmit_retransmit_queue(). We have tcp_simple_retransmit() and
tcp_rcv_fastopen_synack() share code in this way because in both cases
we get a packet indicating non-congestion loss (MTU reduction or TFO
failure) and thus in both cases we want to retransmit as many packets
as cwnd allows, without reducing cwnd. And given that retransmits will
set retrans_stamp to a non-zero value (and may do so in a later
calling context due to TSQ), we also want to enter CA_Loss so that we
track when all retransmitted packets are ACked and clear retrans_stamp
when that happens (to ensure later recurring RTOs are using the
correct retrans_stamp and don't declare ETIMEDOUT prematurely).

Fixes: 9e046bb111f1 ("tcp: clear tp-&gt;retrans_stamp in tcp_rcv_fastopen_synack()")
Fixes: a7abf3cd76e1 ("tcp: consider using standard rtx logic in tcp_rcv_fastopen_synack()")
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Link: https://patch.msgid.link/20240624144323.2371403-1-ncardwell.sw@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.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 5dfe9d273932c647bdc9d664f939af9a5a398cbc ]

Testing determined that the recent commit 9e046bb111f1 ("tcp: clear
tp-&gt;retrans_stamp in tcp_rcv_fastopen_synack()") has a race, and does
not always ensure retrans_stamp is 0 after a TFO payload retransmit.

If transmit completion for the SYN+data skb happens after the client
TCP stack receives the SYNACK (which sometimes happens), then
retrans_stamp can erroneously remain non-zero for the lifetime of the
connection, causing a premature ETIMEDOUT later.

Testing and tracing showed that the buggy scenario is the following
somewhat tricky sequence:

+ Client attempts a TFO handshake. tcp_send_syn_data() sends SYN + TFO
  cookie + data in a single packet in the syn_data skb. It hands the
  syn_data skb to tcp_transmit_skb(), which makes a clone. Crucially,
  it then reuses the same original (non-clone) syn_data skb,
  transforming it by advancing the seq by one byte and removing the
  FIN bit, and enques the resulting payload-only skb in the
  sk-&gt;tcp_rtx_queue.

+ Client sets retrans_stamp to the start time of the three-way
  handshake.

+ Cookie mismatches or server has TFO disabled, and server only ACKs
  SYN.

+ tcp_ack() sees SYN is acked, tcp_clean_rtx_queue() clears
  retrans_stamp.

+ Since the client SYN was acked but not the payload, the TFO failure
  code path in tcp_rcv_fastopen_synack() tries to retransmit the
  payload skb.  However, in some cases the transmit completion for the
  clone of the syn_data (which had SYN + TFO cookie + data) hasn't
  happened.  In those cases, skb_still_in_host_queue() returns true
  for the retransmitted TFO payload, because the clone of the syn_data
  skb has not had its tx completetion.

+ Because skb_still_in_host_queue() finds skb_fclone_busy() is true,
  it sets the TSQ_THROTTLED bit and the retransmit does not happen in
  the tcp_rcv_fastopen_synack() call chain.

+ The tcp_rcv_fastopen_synack() code next implicitly assumes the
  retransmit process is finished, and sets retrans_stamp to 0 to clear
  it, but this is later overwritten (see below).

+ Later, upon tx completion, tcp_tsq_write() calls
  tcp_xmit_retransmit_queue(), which puts the retransmit in flight and
  sets retrans_stamp to a non-zero value.

+ The client receives an ACK for the retransmitted TFO payload data.

+ Since we're in CA_Open and there are no dupacks/SACKs/DSACKs/ECN to
  make tcp_ack_is_dubious() true and make us call
  tcp_fastretrans_alert() and reach a code path that clears
  retrans_stamp, retrans_stamp stays nonzero.

+ Later, if there is a TLP, RTO, RTO sequence, then the connection
  will suffer an early ETIMEDOUT due to the erroneously ancient
  retrans_stamp.

The fix: this commit refactors the code to have
tcp_rcv_fastopen_synack() retransmit by reusing the relevant parts of
tcp_simple_retransmit() that enter CA_Loss (without changing cwnd) and
call tcp_xmit_retransmit_queue(). We have tcp_simple_retransmit() and
tcp_rcv_fastopen_synack() share code in this way because in both cases
we get a packet indicating non-congestion loss (MTU reduction or TFO
failure) and thus in both cases we want to retransmit as many packets
as cwnd allows, without reducing cwnd. And given that retransmits will
set retrans_stamp to a non-zero value (and may do so in a later
calling context due to TSQ), we also want to enter CA_Loss so that we
track when all retransmitted packets are ACked and clear retrans_stamp
when that happens (to ensure later recurring RTOs are using the
correct retrans_stamp and don't declare ETIMEDOUT prematurely).

Fixes: 9e046bb111f1 ("tcp: clear tp-&gt;retrans_stamp in tcp_rcv_fastopen_synack()")
Fixes: a7abf3cd76e1 ("tcp: consider using standard rtx logic in tcp_rcv_fastopen_synack()")
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Yuchung Cheng &lt;ycheng@google.com&gt;
Link: https://patch.msgid.link/20240624144323.2371403-1-ncardwell.sw@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Fix race for duplicate reqsk on identical SYN</title>
<updated>2024-07-05T07:33:48+00:00</updated>
<author>
<name>luoxuanqiang</name>
<email>luoxuanqiang@kylinos.cn</email>
</author>
<published>2024-06-21T01:39:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fdae4d139f4778b20a40c60705c53f5f146459b5'/>
<id>fdae4d139f4778b20a40c60705c53f5f146459b5</id>
<content type='text'>
[ Upstream commit ff46e3b4421923937b7f6e44ffcd3549a074f321 ]

When bonding is configured in BOND_MODE_BROADCAST mode, if two identical
SYN packets are received at the same time and processed on different CPUs,
it can potentially create the same sk (sock) but two different reqsk
(request_sock) in tcp_conn_request().

These two different reqsk will respond with two SYNACK packets, and since
the generation of the seq (ISN) incorporates a timestamp, the final two
SYNACK packets will have different seq values.

The consequence is that when the Client receives and replies with an ACK
to the earlier SYNACK packet, we will reset(RST) it.

========================================================================

This behavior is consistently reproducible in my local setup,
which comprises:

                  | NETA1 ------ NETB1 |
PC_A --- bond --- |                    | --- bond --- PC_B
                  | NETA2 ------ NETB2 |

- PC_A is the Server and has two network cards, NETA1 and NETA2. I have
  bonded these two cards using BOND_MODE_BROADCAST mode and configured
  them to be handled by different CPU.

- PC_B is the Client, also equipped with two network cards, NETB1 and
  NETB2, which are also bonded and configured in BOND_MODE_BROADCAST mode.

If the client attempts a TCP connection to the server, it might encounter
a failure. Capturing packets from the server side reveals:

10.10.10.10.45182 &gt; localhost: Flags [S], seq 320236027,
10.10.10.10.45182 &gt; localhost: Flags [S], seq 320236027,
localhost &gt; 10.10.10.10.45182: Flags [S.], seq 2967855116,
localhost &gt; 10.10.10.10.45182: Flags [S.], seq 2967855123, &lt;==
10.10.10.10.45182 &gt; localhost: Flags [.], ack 4294967290,
10.10.10.10.45182 &gt; localhost: Flags [.], ack 4294967290,
localhost &gt; 10.10.10.10.45182: Flags [R], seq 2967855117, &lt;==
localhost &gt; 10.10.10.10.45182: Flags [R], seq 2967855117,

Two SYNACKs with different seq numbers are sent by localhost,
resulting in an anomaly.

========================================================================

The attempted solution is as follows:
Add a return value to inet_csk_reqsk_queue_hash_add() to confirm if the
ehash insertion is successful (Up to now, the reason for unsuccessful
insertion is that a reqsk for the same connection has already been
inserted). If the insertion fails, release the reqsk.

Due to the refcnt, Kuniyuki suggests also adding a return value check
for the DCCP module; if ehash insertion fails, indicating a successful
insertion of the same connection, simply release the reqsk as well.

Simultaneously, In the reqsk_queue_hash_req(), the start of the
req-&gt;rsk_timer is adjusted to be after successful insertion.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: luoxuanqiang &lt;luoxuanqiang@kylinos.cn&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240621013929.1386815-1-luoxuanqiang@kylinos.cn
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&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 ff46e3b4421923937b7f6e44ffcd3549a074f321 ]

When bonding is configured in BOND_MODE_BROADCAST mode, if two identical
SYN packets are received at the same time and processed on different CPUs,
it can potentially create the same sk (sock) but two different reqsk
(request_sock) in tcp_conn_request().

These two different reqsk will respond with two SYNACK packets, and since
the generation of the seq (ISN) incorporates a timestamp, the final two
SYNACK packets will have different seq values.

The consequence is that when the Client receives and replies with an ACK
to the earlier SYNACK packet, we will reset(RST) it.

========================================================================

This behavior is consistently reproducible in my local setup,
which comprises:

                  | NETA1 ------ NETB1 |
PC_A --- bond --- |                    | --- bond --- PC_B
                  | NETA2 ------ NETB2 |

- PC_A is the Server and has two network cards, NETA1 and NETA2. I have
  bonded these two cards using BOND_MODE_BROADCAST mode and configured
  them to be handled by different CPU.

- PC_B is the Client, also equipped with two network cards, NETB1 and
  NETB2, which are also bonded and configured in BOND_MODE_BROADCAST mode.

If the client attempts a TCP connection to the server, it might encounter
a failure. Capturing packets from the server side reveals:

10.10.10.10.45182 &gt; localhost: Flags [S], seq 320236027,
10.10.10.10.45182 &gt; localhost: Flags [S], seq 320236027,
localhost &gt; 10.10.10.10.45182: Flags [S.], seq 2967855116,
localhost &gt; 10.10.10.10.45182: Flags [S.], seq 2967855123, &lt;==
10.10.10.10.45182 &gt; localhost: Flags [.], ack 4294967290,
10.10.10.10.45182 &gt; localhost: Flags [.], ack 4294967290,
localhost &gt; 10.10.10.10.45182: Flags [R], seq 2967855117, &lt;==
localhost &gt; 10.10.10.10.45182: Flags [R], seq 2967855117,

Two SYNACKs with different seq numbers are sent by localhost,
resulting in an anomaly.

========================================================================

The attempted solution is as follows:
Add a return value to inet_csk_reqsk_queue_hash_add() to confirm if the
ehash insertion is successful (Up to now, the reason for unsuccessful
insertion is that a reqsk for the same connection has already been
inserted). If the insertion fails, release the reqsk.

Due to the refcnt, Kuniyuki suggests also adding a return value check
for the DCCP module; if ehash insertion fails, indicating a successful
insertion of the same connection, simply release the reqsk as well.

Simultaneously, In the reqsk_queue_hash_req(), the start of the
req-&gt;rsk_timer is adjusted to be after successful insertion.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: luoxuanqiang &lt;luoxuanqiang@kylinos.cn&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240621013929.1386815-1-luoxuanqiang@kylinos.cn
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: clear tp-&gt;retrans_stamp in tcp_rcv_fastopen_synack()</title>
<updated>2024-06-27T11:49:13+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-06-14T13:06:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=250fad18b0c959b137ad745428fb411f1ac1bbc6'/>
<id>250fad18b0c959b137ad745428fb411f1ac1bbc6</id>
<content type='text'>
commit 9e046bb111f13461d3f9331e24e974324245140e upstream.

Some applications were reporting ETIMEDOUT errors on apparently
good looking flows, according to packet dumps.

We were able to root cause the issue to an accidental setting
of tp-&gt;retrans_stamp in the following scenario:

- client sends TFO SYN with data.
- server has TFO disabled, ACKs only SYN but not payload.
- client receives SYNACK covering only SYN.
- tcp_ack() eats SYN and sets tp-&gt;retrans_stamp to 0.
- tcp_rcv_fastopen_synack() calls tcp_xmit_retransmit_queue()
  to retransmit TFO payload w/o SYN, sets tp-&gt;retrans_stamp to "now",
  but we are not in any loss recovery state.
- TFO payload is ACKed.
- we are not in any loss recovery state, and don't see any dupacks,
  so we don't get to any code path that clears tp-&gt;retrans_stamp.
- tp-&gt;retrans_stamp stays non-zero for the lifetime of the connection.
- after first RTO, tcp_clamp_rto_to_user_timeout() clamps second RTO
  to 1 jiffy due to bogus tp-&gt;retrans_stamp.
- on clamped RTO with non-zero icsk_retransmits, retransmits_timed_out()
  sets start_ts from tp-&gt;retrans_stamp from TFO payload retransmit
  hours/days ago, and computes bogus long elapsed time for loss recovery,
  and suffers ETIMEDOUT early.

Fixes: a7abf3cd76e1 ("tcp: consider using standard rtx logic in tcp_rcv_fastopen_synack()")
CC: stable@vger.kernel.org
Co-developed-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Co-developed-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240614130615.396837-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.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 9e046bb111f13461d3f9331e24e974324245140e upstream.

Some applications were reporting ETIMEDOUT errors on apparently
good looking flows, according to packet dumps.

We were able to root cause the issue to an accidental setting
of tp-&gt;retrans_stamp in the following scenario:

- client sends TFO SYN with data.
- server has TFO disabled, ACKs only SYN but not payload.
- client receives SYNACK covering only SYN.
- tcp_ack() eats SYN and sets tp-&gt;retrans_stamp to 0.
- tcp_rcv_fastopen_synack() calls tcp_xmit_retransmit_queue()
  to retransmit TFO payload w/o SYN, sets tp-&gt;retrans_stamp to "now",
  but we are not in any loss recovery state.
- TFO payload is ACKed.
- we are not in any loss recovery state, and don't see any dupacks,
  so we don't get to any code path that clears tp-&gt;retrans_stamp.
- tp-&gt;retrans_stamp stays non-zero for the lifetime of the connection.
- after first RTO, tcp_clamp_rto_to_user_timeout() clamps second RTO
  to 1 jiffy due to bogus tp-&gt;retrans_stamp.
- on clamped RTO with non-zero icsk_retransmits, retransmits_timed_out()
  sets start_ts from tp-&gt;retrans_stamp from TFO payload retransmit
  hours/days ago, and computes bogus long elapsed time for loss recovery,
  and suffers ETIMEDOUT early.

Fixes: a7abf3cd76e1 ("tcp: consider using standard rtx logic in tcp_rcv_fastopen_synack()")
CC: stable@vger.kernel.org
Co-developed-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Signed-off-by: Neal Cardwell &lt;ncardwell@google.com&gt;
Co-developed-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Yuchung Cheng &lt;ycheng@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240614130615.396837-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cipso: fix total option length computation</title>
<updated>2024-06-27T11:49:06+00:00</updated>
<author>
<name>Ondrej Mosnacek</name>
<email>omosnace@redhat.com</email>
</author>
<published>2024-06-07T16:07:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=08fa10b26592b72a2af78871082fa1970adcb78b'/>
<id>08fa10b26592b72a2af78871082fa1970adcb78b</id>
<content type='text'>
[ Upstream commit 9f36169912331fa035d7b73a91252d7c2512eb1a ]

As evident from the definition of ip_options_get(), the IP option
IPOPT_END is used to pad the IP option data array, not IPOPT_NOP. Yet
the loop that walks the IP options to determine the total IP options
length in cipso_v4_delopt() doesn't take IPOPT_END into account.

Fix it by recognizing the IPOPT_END value as the end of actual options.

Fixes: 014ab19a69c3 ("selinux: Set socket NetLabel based on connection endpoint")
Signed-off-by: Ondrej Mosnacek &lt;omosnace@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 9f36169912331fa035d7b73a91252d7c2512eb1a ]

As evident from the definition of ip_options_get(), the IP option
IPOPT_END is used to pad the IP option data array, not IPOPT_NOP. Yet
the loop that walks the IP options to determine the total IP options
length in cipso_v4_delopt() doesn't take IPOPT_END into account.

Fix it by recognizing the IPOPT_END value as the end of actual options.

Fixes: 014ab19a69c3 ("selinux: Set socket NetLabel based on connection endpoint")
Signed-off-by: Ondrej Mosnacek &lt;omosnace@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>tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB</title>
<updated>2024-06-21T12:38:17+00:00</updated>
<author>
<name>Jason Xing</name>
<email>kernelxing@tencent.com</email>
</author>
<published>2024-06-03T17:02:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=acdf17546ef8ee73c94e442e3f4b933e42c3dfac'/>
<id>acdf17546ef8ee73c94e442e3f4b933e42c3dfac</id>
<content type='text'>
[ Upstream commit a46d0ea5c94205f40ecf912d1bb7806a8a64704f ]

According to RFC 1213, we should also take CLOSE-WAIT sockets into
consideration:

  "tcpCurrEstab OBJECT-TYPE
   ...
   The number of TCP connections for which the current state
   is either ESTABLISHED or CLOSE- WAIT."

After this, CurrEstab counter will display the total number of
ESTABLISHED and CLOSE-WAIT sockets.

The logic of counting
When we increment the counter?
a) if we change the state to ESTABLISHED.
b) if we change the state from SYN-RECEIVED to CLOSE-WAIT.

When we decrement the counter?
a) if the socket leaves ESTABLISHED and will never go into CLOSE-WAIT,
say, on the client side, changing from ESTABLISHED to FIN-WAIT-1.
b) if the socket leaves CLOSE-WAIT, say, on the server side, changing
from CLOSE-WAIT to LAST-ACK.

Please note: there are two chances that old state of socket can be changed
to CLOSE-WAIT in tcp_fin(). One is SYN-RECV, the other is ESTABLISHED.
So we have to take care of the former case.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason Xing &lt;kernelxing@tencent.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.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 a46d0ea5c94205f40ecf912d1bb7806a8a64704f ]

According to RFC 1213, we should also take CLOSE-WAIT sockets into
consideration:

  "tcpCurrEstab OBJECT-TYPE
   ...
   The number of TCP connections for which the current state
   is either ESTABLISHED or CLOSE- WAIT."

After this, CurrEstab counter will display the total number of
ESTABLISHED and CLOSE-WAIT sockets.

The logic of counting
When we increment the counter?
a) if we change the state to ESTABLISHED.
b) if we change the state from SYN-RECEIVED to CLOSE-WAIT.

When we decrement the counter?
a) if the socket leaves ESTABLISHED and will never go into CLOSE-WAIT,
say, on the client side, changing from ESTABLISHED to FIN-WAIT-1.
b) if the socket leaves CLOSE-WAIT, say, on the server side, changing
from CLOSE-WAIT to LAST-ACK.

Please note: there are two chances that old state of socket can be changed
to CLOSE-WAIT in tcp_fin(). One is SYN-RECV, the other is ESTABLISHED.
So we have to take care of the former case.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason Xing &lt;kernelxing@tencent.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.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>net: tls: fix marking packets as decrypted</title>
<updated>2024-06-21T12:38:16+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2024-05-30T23:26:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=50569d12945f86fa4b321c4b1c3005874dbaa0f1'/>
<id>50569d12945f86fa4b321c4b1c3005874dbaa0f1</id>
<content type='text'>
[ Upstream commit a535d59432370343058755100ee75ab03c0e3f91 ]

For TLS offload we mark packets with skb-&gt;decrypted to make sure
they don't escape the host without getting encrypted first.
The crypto state lives in the socket, so it may get detached
by a call to skb_orphan(). As a safety check - the egress path
drops all packets with skb-&gt;decrypted and no "crypto-safe" socket.

The skb marking was added to sendpage only (and not sendmsg),
because tls_device injected data into the TCP stack using sendpage.
This special case was missed when sendpage got folded into sendmsg.

Fixes: c5c37af6ecad ("tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES")
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240530232607.82686-1-kuba@kernel.org
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&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 a535d59432370343058755100ee75ab03c0e3f91 ]

For TLS offload we mark packets with skb-&gt;decrypted to make sure
they don't escape the host without getting encrypted first.
The crypto state lives in the socket, so it may get detached
by a call to skb_orphan(). As a safety check - the egress path
drops all packets with skb-&gt;decrypted and no "crypto-safe" socket.

The skb marking was added to sendpage only (and not sendmsg),
because tls_device injected data into the TCP stack using sendpage.
This special case was missed when sendpage got folded into sendmsg.

Fixes: c5c37af6ecad ("tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES")
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20240530232607.82686-1-kuba@kernel.org
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: fix __dst_negative_advice() race</title>
<updated>2024-06-16T11:47:44+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-05-28T11:43:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5af198c387128a9d2ddd620b0f0803564a4d4508'/>
<id>5af198c387128a9d2ddd620b0f0803564a4d4508</id>
<content type='text'>
commit 92f1655aa2b2294d0b49925f3b875a634bd3b59e upstream.

__dst_negative_advice() does not enforce proper RCU rules when
sk-&gt;dst_cache must be cleared, leading to possible UAF.

RCU rules are that we must first clear sk-&gt;sk_dst_cache,
then call dst_release(old_dst).

Note that sk_dst_reset(sk) is implementing this protocol correctly,
while __dst_negative_advice() uses the wrong order.

Given that ip6_negative_advice() has special logic
against RTF_CACHE, this means each of the three -&gt;negative_advice()
existing methods must perform the sk_dst_reset() themselves.

Note the check against NULL dst is centralized in
__dst_negative_advice(), there is no need to duplicate
it in various callbacks.

Many thanks to Clement Lecigne for tracking this issue.

This old bug became visible after the blamed commit, using UDP sockets.

Fixes: a87cb3e48ee8 ("net: Facility to report route quality of connected sockets")
Reported-by: Clement Lecigne &lt;clecigne@google.com&gt;
Diagnosed-by: Clement Lecigne &lt;clecigne@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Tom Herbert &lt;tom@herbertland.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://lore.kernel.org/r/20240528114353.1794151-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
[Lee: Stable backport]
Signed-off-by: Lee Jones &lt;lee@kernel.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 92f1655aa2b2294d0b49925f3b875a634bd3b59e upstream.

__dst_negative_advice() does not enforce proper RCU rules when
sk-&gt;dst_cache must be cleared, leading to possible UAF.

RCU rules are that we must first clear sk-&gt;sk_dst_cache,
then call dst_release(old_dst).

Note that sk_dst_reset(sk) is implementing this protocol correctly,
while __dst_negative_advice() uses the wrong order.

Given that ip6_negative_advice() has special logic
against RTF_CACHE, this means each of the three -&gt;negative_advice()
existing methods must perform the sk_dst_reset() themselves.

Note the check against NULL dst is centralized in
__dst_negative_advice(), there is no need to duplicate
it in various callbacks.

Many thanks to Clement Lecigne for tracking this issue.

This old bug became visible after the blamed commit, using UDP sockets.

Fixes: a87cb3e48ee8 ("net: Facility to report route quality of connected sockets")
Reported-by: Clement Lecigne &lt;clecigne@google.com&gt;
Diagnosed-by: Clement Lecigne &lt;clecigne@google.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Tom Herbert &lt;tom@herbertland.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://lore.kernel.org/r/20240528114353.1794151-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
[Lee: Stable backport]
Signed-off-by: Lee Jones &lt;lee@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netfilter: tproxy: bail out if IP has been disabled on the device</title>
<updated>2024-06-12T09:12:57+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2024-05-13T10:27:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=570b4c52096e62fda562448f5760fd0ff06110f0'/>
<id>570b4c52096e62fda562448f5760fd0ff06110f0</id>
<content type='text'>
[ Upstream commit 21a673bddc8fd4873c370caf9ae70ffc6d47e8d3 ]

syzbot reports:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
[..]
RIP: 0010:nf_tproxy_laddr4+0xb7/0x340 net/ipv4/netfilter/nf_tproxy_ipv4.c:62
Call Trace:
 nft_tproxy_eval_v4 net/netfilter/nft_tproxy.c:56 [inline]
 nft_tproxy_eval+0xa9a/0x1a00 net/netfilter/nft_tproxy.c:168

__in_dev_get_rcu() can return NULL, so check for this.

Reported-and-tested-by: syzbot+b94a6818504ea90d7661@syzkaller.appspotmail.com
Fixes: cc6eb4338569 ("tproxy: use the interface primary IP address as a default value for --on-ip")
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 21a673bddc8fd4873c370caf9ae70ffc6d47e8d3 ]

syzbot reports:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
[..]
RIP: 0010:nf_tproxy_laddr4+0xb7/0x340 net/ipv4/netfilter/nf_tproxy_ipv4.c:62
Call Trace:
 nft_tproxy_eval_v4 net/netfilter/nft_tproxy.c:56 [inline]
 nft_tproxy_eval+0xa9a/0x1a00 net/netfilter/nft_tproxy.c:168

__in_dev_get_rcu() can return NULL, so check for this.

Reported-and-tested-by: syzbot+b94a6818504ea90d7661@syzkaller.appspotmail.com
Fixes: cc6eb4338569 ("tproxy: use the interface primary IP address as a default value for --on-ip")
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>net: relax socket state check at accept time.</title>
<updated>2024-06-12T09:12:50+00:00</updated>
<author>
<name>Paolo Abeni</name>
<email>pabeni@redhat.com</email>
</author>
<published>2024-05-21T14:01:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=87bdc9f6f58b4417362d6932b49b828e319f97dc'/>
<id>87bdc9f6f58b4417362d6932b49b828e319f97dc</id>
<content type='text'>
[ Upstream commit 26afda78cda3da974fd4c287962c169e9462c495 ]

Christoph reported the following splat:

WARNING: CPU: 1 PID: 772 at net/ipv4/af_inet.c:761 __inet_accept+0x1f4/0x4a0
Modules linked in:
CPU: 1 PID: 772 Comm: syz-executor510 Not tainted 6.9.0-rc7-g7da7119fe22b #56
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
RIP: 0010:__inet_accept+0x1f4/0x4a0 net/ipv4/af_inet.c:759
Code: 04 38 84 c0 0f 85 87 00 00 00 41 c7 04 24 03 00 00 00 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 ec b7 da fd &lt;0f&gt; 0b e9 7f fe ff ff e8 e0 b7 da fd 0f 0b e9 fe fe ff ff 89 d9 80
RSP: 0018:ffffc90000c2fc58 EFLAGS: 00010293
RAX: ffffffff836bdd14 RBX: 0000000000000000 RCX: ffff888104668000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff836bdb89 R09: fffff52000185f64
R10: dffffc0000000000 R11: fffff52000185f64 R12: dffffc0000000000
R13: 1ffff92000185f98 R14: ffff88810754d880 R15: ffff8881007b7800
FS:  000000001c772880(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9fcf2e178 CR3: 00000001045d2002 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 &lt;TASK&gt;
 inet_accept+0x138/0x1d0 net/ipv4/af_inet.c:786
 do_accept+0x435/0x620 net/socket.c:1929
 __sys_accept4_file net/socket.c:1969 [inline]
 __sys_accept4+0x9b/0x110 net/socket.c:1999
 __do_sys_accept net/socket.c:2016 [inline]
 __se_sys_accept net/socket.c:2013 [inline]
 __x64_sys_accept+0x7d/0x90 net/socket.c:2013
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0x100 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x4315f9
Code: fd ff 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 0f 83 ab b4 fd ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdb26d9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 0000000000400300 RCX: 00000000004315f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006e1018 R08: 0000000000400300 R09: 0000000000400300
R10: 0000000000400300 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000040cdf0 R14: 000000000040ce80 R15: 0000000000000055
 &lt;/TASK&gt;

The reproducer invokes shutdown() before entering the listener status.
After commit 94062790aedb ("tcp: defer shutdown(SEND_SHUTDOWN) for
TCP_SYN_RECV sockets"), the above causes the child to reach the accept
syscall in FIN_WAIT1 status.

Eric noted we can relax the existing assertion in __inet_accept()

Reported-by: Christoph Paasch &lt;cpaasch@apple.com&gt;
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/490
Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 94062790aedb ("tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets")
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/23ab880a44d8cfd967e84de8b93dbf48848e3d8c.1716299669.git.pabeni@redhat.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&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 26afda78cda3da974fd4c287962c169e9462c495 ]

Christoph reported the following splat:

WARNING: CPU: 1 PID: 772 at net/ipv4/af_inet.c:761 __inet_accept+0x1f4/0x4a0
Modules linked in:
CPU: 1 PID: 772 Comm: syz-executor510 Not tainted 6.9.0-rc7-g7da7119fe22b #56
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
RIP: 0010:__inet_accept+0x1f4/0x4a0 net/ipv4/af_inet.c:759
Code: 04 38 84 c0 0f 85 87 00 00 00 41 c7 04 24 03 00 00 00 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 ec b7 da fd &lt;0f&gt; 0b e9 7f fe ff ff e8 e0 b7 da fd 0f 0b e9 fe fe ff ff 89 d9 80
RSP: 0018:ffffc90000c2fc58 EFLAGS: 00010293
RAX: ffffffff836bdd14 RBX: 0000000000000000 RCX: ffff888104668000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff836bdb89 R09: fffff52000185f64
R10: dffffc0000000000 R11: fffff52000185f64 R12: dffffc0000000000
R13: 1ffff92000185f98 R14: ffff88810754d880 R15: ffff8881007b7800
FS:  000000001c772880(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9fcf2e178 CR3: 00000001045d2002 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 &lt;TASK&gt;
 inet_accept+0x138/0x1d0 net/ipv4/af_inet.c:786
 do_accept+0x435/0x620 net/socket.c:1929
 __sys_accept4_file net/socket.c:1969 [inline]
 __sys_accept4+0x9b/0x110 net/socket.c:1999
 __do_sys_accept net/socket.c:2016 [inline]
 __se_sys_accept net/socket.c:2013 [inline]
 __x64_sys_accept+0x7d/0x90 net/socket.c:2013
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0x100 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x4315f9
Code: fd ff 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 0f 83 ab b4 fd ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdb26d9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 0000000000400300 RCX: 00000000004315f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000006e1018 R08: 0000000000400300 R09: 0000000000400300
R10: 0000000000400300 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000040cdf0 R14: 000000000040ce80 R15: 0000000000000055
 &lt;/TASK&gt;

The reproducer invokes shutdown() before entering the listener status.
After commit 94062790aedb ("tcp: defer shutdown(SEND_SHUTDOWN) for
TCP_SYN_RECV sockets"), the above causes the child to reach the accept
syscall in FIN_WAIT1 status.

Eric noted we can relax the existing assertion in __inet_accept()

Reported-by: Christoph Paasch &lt;cpaasch@apple.com&gt;
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/490
Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 94062790aedb ("tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets")
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/23ab880a44d8cfd967e84de8b93dbf48848e3d8c.1716299669.git.pabeni@redhat.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: Fix shift-out-of-bounds in dctcp_update_alpha().</title>
<updated>2024-06-12T09:12:48+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2024-05-17T09:16:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=02261d3f9dc7d1d7be7d778f839e3404ab99034c'/>
<id>02261d3f9dc7d1d7be7d778f839e3404ab99034c</id>
<content type='text'>
[ Upstream commit 3ebc46ca8675de6378e3f8f40768e180bb8afa66 ]

In dctcp_update_alpha(), we use a module parameter dctcp_shift_g
as follows:

  alpha -= min_not_zero(alpha, alpha &gt;&gt; dctcp_shift_g);
  ...
  delivered_ce &lt;&lt;= (10 - dctcp_shift_g);

It seems syzkaller started fuzzing module parameters and triggered
shift-out-of-bounds [0] by setting 100 to dctcp_shift_g:

  memcpy((void*)0x20000080,
         "/sys/module/tcp_dctcp/parameters/dctcp_shift_g\000", 47);
  res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x20000080ul,
                /*flags=*/2ul, /*mode=*/0ul);
  memcpy((void*)0x20000000, "100\000", 4);
  syscall(__NR_write, /*fd=*/r[0], /*val=*/0x20000000ul, /*len=*/4ul);

Let's limit the max value of dctcp_shift_g by param_set_uint_minmax().

With this patch:

  # echo 10 &gt; /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  # cat /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  10
  # echo 11 &gt; /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  -bash: echo: write error: Invalid argument

[0]:
UBSAN: shift-out-of-bounds in net/ipv4/tcp_dctcp.c:143:12
shift exponent 100 is too large for 32-bit type 'u32' (aka 'unsigned int')
CPU: 0 PID: 8083 Comm: syz-executor345 Not tainted 6.9.0-05151-g1b294a1f3561 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x201/0x300 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x346/0x3a0 lib/ubsan.c:468
 dctcp_update_alpha+0x540/0x570 net/ipv4/tcp_dctcp.c:143
 tcp_in_ack_event net/ipv4/tcp_input.c:3802 [inline]
 tcp_ack+0x17b1/0x3bc0 net/ipv4/tcp_input.c:3948
 tcp_rcv_state_process+0x57a/0x2290 net/ipv4/tcp_input.c:6711
 tcp_v4_do_rcv+0x764/0xc40 net/ipv4/tcp_ipv4.c:1937
 sk_backlog_rcv include/net/sock.h:1106 [inline]
 __release_sock+0x20f/0x350 net/core/sock.c:2983
 release_sock+0x61/0x1f0 net/core/sock.c:3549
 mptcp_subflow_shutdown+0x3d0/0x620 net/mptcp/protocol.c:2907
 mptcp_check_send_data_fin+0x225/0x410 net/mptcp/protocol.c:2976
 __mptcp_close+0x238/0xad0 net/mptcp/protocol.c:3072
 mptcp_close+0x2a/0x1a0 net/mptcp/protocol.c:3127
 inet_release+0x190/0x1f0 net/ipv4/af_inet.c:437
 __sock_release net/socket.c:659 [inline]
 sock_close+0xc0/0x240 net/socket.c:1421
 __fput+0x41b/0x890 fs/file_table.c:422
 task_work_run+0x23b/0x300 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x9c8/0x2540 kernel/exit.c:878
 do_group_exit+0x201/0x2b0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xe4/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x67/0x6f
RIP: 0033:0x7f6c2b5005b6
Code: Unable to access opcode bytes at 0x7f6c2b50058c.
RSP: 002b:00007ffe883eb948 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f6c2b5862f0 RCX: 00007f6c2b5005b6
RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001
RBP: 0000000000000001 R08: 00000000000000e7 R09: ffffffffffffffc0
R10: 0000000000000006 R11: 0000000000000246 R12: 00007f6c2b5862f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
 &lt;/TASK&gt;

Reported-by: syzkaller &lt;syzkaller@googlegroups.com&gt;
Reported-by: Yue Sun &lt;samsun1006219@gmail.com&gt;
Reported-by: xingwei lee &lt;xrivendell7@gmail.com&gt;
Closes: https://lore.kernel.org/netdev/CAEkJfYNJM=cw-8x7_Vmj1J6uYVCWMbbvD=EFmDPVBGpTsqOxEA@mail.gmail.com/
Fixes: e3118e8359bb ("net: tcp: add DCTCP congestion control algorithm")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://lore.kernel.org/r/20240517091626.32772-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&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 3ebc46ca8675de6378e3f8f40768e180bb8afa66 ]

In dctcp_update_alpha(), we use a module parameter dctcp_shift_g
as follows:

  alpha -= min_not_zero(alpha, alpha &gt;&gt; dctcp_shift_g);
  ...
  delivered_ce &lt;&lt;= (10 - dctcp_shift_g);

It seems syzkaller started fuzzing module parameters and triggered
shift-out-of-bounds [0] by setting 100 to dctcp_shift_g:

  memcpy((void*)0x20000080,
         "/sys/module/tcp_dctcp/parameters/dctcp_shift_g\000", 47);
  res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x20000080ul,
                /*flags=*/2ul, /*mode=*/0ul);
  memcpy((void*)0x20000000, "100\000", 4);
  syscall(__NR_write, /*fd=*/r[0], /*val=*/0x20000000ul, /*len=*/4ul);

Let's limit the max value of dctcp_shift_g by param_set_uint_minmax().

With this patch:

  # echo 10 &gt; /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  # cat /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  10
  # echo 11 &gt; /sys/module/tcp_dctcp/parameters/dctcp_shift_g
  -bash: echo: write error: Invalid argument

[0]:
UBSAN: shift-out-of-bounds in net/ipv4/tcp_dctcp.c:143:12
shift exponent 100 is too large for 32-bit type 'u32' (aka 'unsigned int')
CPU: 0 PID: 8083 Comm: syz-executor345 Not tainted 6.9.0-05151-g1b294a1f3561 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 &lt;TASK&gt;
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x201/0x300 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x346/0x3a0 lib/ubsan.c:468
 dctcp_update_alpha+0x540/0x570 net/ipv4/tcp_dctcp.c:143
 tcp_in_ack_event net/ipv4/tcp_input.c:3802 [inline]
 tcp_ack+0x17b1/0x3bc0 net/ipv4/tcp_input.c:3948
 tcp_rcv_state_process+0x57a/0x2290 net/ipv4/tcp_input.c:6711
 tcp_v4_do_rcv+0x764/0xc40 net/ipv4/tcp_ipv4.c:1937
 sk_backlog_rcv include/net/sock.h:1106 [inline]
 __release_sock+0x20f/0x350 net/core/sock.c:2983
 release_sock+0x61/0x1f0 net/core/sock.c:3549
 mptcp_subflow_shutdown+0x3d0/0x620 net/mptcp/protocol.c:2907
 mptcp_check_send_data_fin+0x225/0x410 net/mptcp/protocol.c:2976
 __mptcp_close+0x238/0xad0 net/mptcp/protocol.c:3072
 mptcp_close+0x2a/0x1a0 net/mptcp/protocol.c:3127
 inet_release+0x190/0x1f0 net/ipv4/af_inet.c:437
 __sock_release net/socket.c:659 [inline]
 sock_close+0xc0/0x240 net/socket.c:1421
 __fput+0x41b/0x890 fs/file_table.c:422
 task_work_run+0x23b/0x300 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x9c8/0x2540 kernel/exit.c:878
 do_group_exit+0x201/0x2b0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xe4/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x67/0x6f
RIP: 0033:0x7f6c2b5005b6
Code: Unable to access opcode bytes at 0x7f6c2b50058c.
RSP: 002b:00007ffe883eb948 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f6c2b5862f0 RCX: 00007f6c2b5005b6
RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001
RBP: 0000000000000001 R08: 00000000000000e7 R09: ffffffffffffffc0
R10: 0000000000000006 R11: 0000000000000246 R12: 00007f6c2b5862f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
 &lt;/TASK&gt;

Reported-by: syzkaller &lt;syzkaller@googlegroups.com&gt;
Reported-by: Yue Sun &lt;samsun1006219@gmail.com&gt;
Reported-by: xingwei lee &lt;xrivendell7@gmail.com&gt;
Closes: https://lore.kernel.org/netdev/CAEkJfYNJM=cw-8x7_Vmj1J6uYVCWMbbvD=EFmDPVBGpTsqOxEA@mail.gmail.com/
Fixes: e3118e8359bb ("net: tcp: add DCTCP congestion control algorithm")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://lore.kernel.org/r/20240517091626.32772-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
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