<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/bluetooth, branch v6.7.9</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Bluetooth: Enforce validation on max value of connection interval</title>
<updated>2024-03-06T14:53:51+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2024-01-25T06:50:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9560cc4407e1c214bce7d28410d955aad10a0e06'/>
<id>9560cc4407e1c214bce7d28410d955aad10a0e06</id>
<content type='text'>
[ Upstream commit e4b019515f950b4e6e5b74b2e1bb03a90cb33039 ]

Right now Linux BT stack cannot pass test case "GAP/CONN/CPUP/BV-05-C
'Connection Parameter Update Procedure Invalid Parameters Central
Responder'" in Bluetooth Test Suite revision GAP.TS.p44. [0]

That was revoled by commit c49a8682fc5d ("Bluetooth: validate BLE
connection interval updates"), but later got reverted due to devices
like keyboards and mice may require low connection interval.

So only validate the max value connection interval to pass the Test
Suite, and let devices to request low connection interval if needed.

[0] https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=229869

Fixes: 68d19d7d9957 ("Revert "Bluetooth: validate BLE connection interval updates"")
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 e4b019515f950b4e6e5b74b2e1bb03a90cb33039 ]

Right now Linux BT stack cannot pass test case "GAP/CONN/CPUP/BV-05-C
'Connection Parameter Update Procedure Invalid Parameters Central
Responder'" in Bluetooth Test Suite revision GAP.TS.p44. [0]

That was revoled by commit c49a8682fc5d ("Bluetooth: validate BLE
connection interval updates"), but later got reverted due to devices
like keyboards and mice may require low connection interval.

So only validate the max value connection interval to pass the Test
Suite, and let devices to request low connection interval if needed.

[0] https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=229869

Fixes: 68d19d7d9957 ("Revert "Bluetooth: validate BLE connection interval updates"")
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: hci_event: Fix handling of HCI_EV_IO_CAPA_REQUEST</title>
<updated>2024-03-06T14:53:50+00:00</updated>
<author>
<name>Luiz Augusto von Dentz</name>
<email>luiz.von.dentz@intel.com</email>
</author>
<published>2024-01-22T14:02:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8e2758cc25891d2b76717aaf89b40ed215de188c'/>
<id>8e2758cc25891d2b76717aaf89b40ed215de188c</id>
<content type='text'>
[ Upstream commit 7e74aa53a68bf60f6019bd5d9a9a1406ec4d4865 ]

If we received HCI_EV_IO_CAPA_REQUEST while
HCI_OP_READ_REMOTE_EXT_FEATURES is yet to be responded assume the remote
does support SSP since otherwise this event shouldn't be generated.

Link: https://lore.kernel.org/linux-bluetooth/CABBYNZ+9UdG1cMZVmdtN3U2aS16AKMCyTARZZyFX7xTEDWcMOw@mail.gmail.com/T/#t
Fixes: c7f59461f5a7 ("Bluetooth: Fix a refcnt underflow problem for hci_conn")
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 7e74aa53a68bf60f6019bd5d9a9a1406ec4d4865 ]

If we received HCI_EV_IO_CAPA_REQUEST while
HCI_OP_READ_REMOTE_EXT_FEATURES is yet to be responded assume the remote
does support SSP since otherwise this event shouldn't be generated.

Link: https://lore.kernel.org/linux-bluetooth/CABBYNZ+9UdG1cMZVmdtN3U2aS16AKMCyTARZZyFX7xTEDWcMOw@mail.gmail.com/T/#t
Fixes: c7f59461f5a7 ("Bluetooth: Fix a refcnt underflow problem for hci_conn")
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: hci_event: Fix wrongly recorded wakeup BD_ADDR</title>
<updated>2024-03-06T14:53:50+00:00</updated>
<author>
<name>Zijun Hu</name>
<email>quic_zijuhu@quicinc.com</email>
</author>
<published>2024-01-09T11:03:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ffb06f543c4a5719edddd210913a3b76936fe240'/>
<id>ffb06f543c4a5719edddd210913a3b76936fe240</id>
<content type='text'>
[ Upstream commit 61a5ab72edea7ebc3ad2c6beea29d966f528ebfb ]

hci_store_wake_reason() wrongly parses event HCI_Connection_Request
as HCI_Connection_Complete and HCI_Connection_Complete as
HCI_Connection_Request, so causes recording wakeup BD_ADDR error and
potential stability issue, fix it by using the correct field.

Fixes: 2f20216c1d6f ("Bluetooth: Emit controller suspend and resume events")
Signed-off-by: Zijun Hu &lt;quic_zijuhu@quicinc.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 61a5ab72edea7ebc3ad2c6beea29d966f528ebfb ]

hci_store_wake_reason() wrongly parses event HCI_Connection_Request
as HCI_Connection_Complete and HCI_Connection_Complete as
HCI_Connection_Request, so causes recording wakeup BD_ADDR error and
potential stability issue, fix it by using the correct field.

Fixes: 2f20216c1d6f ("Bluetooth: Emit controller suspend and resume events")
Signed-off-by: Zijun Hu &lt;quic_zijuhu@quicinc.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: hci_sync: Fix accept_list when attempting to suspend</title>
<updated>2024-03-06T14:53:50+00:00</updated>
<author>
<name>Luiz Augusto von Dentz</name>
<email>luiz.von.dentz@intel.com</email>
</author>
<published>2024-01-05T15:43:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c985d7bf40e4946acbcbc33940f1696ca3f058f9'/>
<id>c985d7bf40e4946acbcbc33940f1696ca3f058f9</id>
<content type='text'>
[ Upstream commit e5469adb2a7e930d96813316592302d9f8f1df4e ]

During suspend, only wakeable devices can be in acceptlist, so if the
device was previously added it needs to be removed otherwise the device
can end up waking up the system prematurely.

Fixes: 3b42055388c3 ("Bluetooth: hci_sync: Fix attempting to suspend with unfiltered passive scan")
Signed-off-by: Clancy Shang &lt;clancy.shang@quectel.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Reviewed-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&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 e5469adb2a7e930d96813316592302d9f8f1df4e ]

During suspend, only wakeable devices can be in acceptlist, so if the
device was previously added it needs to be removed otherwise the device
can end up waking up the system prematurely.

Fixes: 3b42055388c3 ("Bluetooth: hci_sync: Fix attempting to suspend with unfiltered passive scan")
Signed-off-by: Clancy Shang &lt;clancy.shang@quectel.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Reviewed-by: Paul Menzel &lt;pmenzel@molgen.mpg.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: Avoid potential use-after-free in hci_error_reset</title>
<updated>2024-03-06T14:53:50+00:00</updated>
<author>
<name>Ying Hsu</name>
<email>yinghsu@chromium.org</email>
</author>
<published>2024-01-04T11:56:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dd594cdc24f2e48dab441732e6dfcafd6b0711d1'/>
<id>dd594cdc24f2e48dab441732e6dfcafd6b0711d1</id>
<content type='text'>
[ Upstream commit 2449007d3f73b2842c9734f45f0aadb522daf592 ]

While handling the HCI_EV_HARDWARE_ERROR event, if the underlying
BT controller is not responding, the GPIO reset mechanism would
free the hci_dev and lead to a use-after-free in hci_error_reset.

Here's the call trace observed on a ChromeOS device with Intel AX201:
   queue_work_on+0x3e/0x6c
   __hci_cmd_sync_sk+0x2ee/0x4c0 [bluetooth &lt;HASH:3b4a6&gt;]
   ? init_wait_entry+0x31/0x31
   __hci_cmd_sync+0x16/0x20 [bluetooth &lt;HASH:3b4a 6&gt;]
   hci_error_reset+0x4f/0xa4 [bluetooth &lt;HASH:3b4a 6&gt;]
   process_one_work+0x1d8/0x33f
   worker_thread+0x21b/0x373
   kthread+0x13a/0x152
   ? pr_cont_work+0x54/0x54
   ? kthread_blkcg+0x31/0x31
    ret_from_fork+0x1f/0x30

This patch holds the reference count on the hci_dev while processing
a HCI_EV_HARDWARE_ERROR event to avoid potential crash.

Fixes: c7741d16a57c ("Bluetooth: Perform a power cycle when receiving hardware error event")
Signed-off-by: Ying Hsu &lt;yinghsu@chromium.org&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 2449007d3f73b2842c9734f45f0aadb522daf592 ]

While handling the HCI_EV_HARDWARE_ERROR event, if the underlying
BT controller is not responding, the GPIO reset mechanism would
free the hci_dev and lead to a use-after-free in hci_error_reset.

Here's the call trace observed on a ChromeOS device with Intel AX201:
   queue_work_on+0x3e/0x6c
   __hci_cmd_sync_sk+0x2ee/0x4c0 [bluetooth &lt;HASH:3b4a6&gt;]
   ? init_wait_entry+0x31/0x31
   __hci_cmd_sync+0x16/0x20 [bluetooth &lt;HASH:3b4a 6&gt;]
   hci_error_reset+0x4f/0xa4 [bluetooth &lt;HASH:3b4a 6&gt;]
   process_one_work+0x1d8/0x33f
   worker_thread+0x21b/0x373
   kthread+0x13a/0x152
   ? pr_cont_work+0x54/0x54
   ? kthread_blkcg+0x31/0x31
    ret_from_fork+0x1f/0x30

This patch holds the reference count on the hci_dev while processing
a HCI_EV_HARDWARE_ERROR event to avoid potential crash.

Fixes: c7741d16a57c ("Bluetooth: Perform a power cycle when receiving hardware error event")
Signed-off-by: Ying Hsu &lt;yinghsu@chromium.org&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: hci_sync: Check the correct flag before starting a scan</title>
<updated>2024-03-06T14:53:50+00:00</updated>
<author>
<name>Jonas Dreßler</name>
<email>verdre@v0yd.nl</email>
</author>
<published>2024-01-02T18:08:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c660f14f224467cb6954465c9f9f7b828ebba4e3'/>
<id>c660f14f224467cb6954465c9f9f7b828ebba4e3</id>
<content type='text'>
[ Upstream commit 6b3899be24b16ff8ee0cb25f0bd59b01b15ba1d1 ]

There's a very confusing mistake in the code starting a HCI inquiry: We're
calling hci_dev_test_flag() to test for HCI_INQUIRY, but hci_dev_test_flag()
checks hdev-&gt;dev_flags instead of hdev-&gt;flags. HCI_INQUIRY is a bit that's
set on hdev-&gt;flags, not on hdev-&gt;dev_flags though.

HCI_INQUIRY equals the integer 7, and in hdev-&gt;dev_flags, 7 means
HCI_BONDABLE, so we were actually checking for HCI_BONDABLE here.

The mistake is only present in the synchronous code for starting an inquiry,
not in the async one. Also devices are typically bondable while doing an
inquiry, so that might be the reason why nobody noticed it so far.

Fixes: abfeea476c68 ("Bluetooth: hci_sync: Convert MGMT_OP_START_DISCOVERY")
Signed-off-by: Jonas Dreßler &lt;verdre@v0yd.nl&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 6b3899be24b16ff8ee0cb25f0bd59b01b15ba1d1 ]

There's a very confusing mistake in the code starting a HCI inquiry: We're
calling hci_dev_test_flag() to test for HCI_INQUIRY, but hci_dev_test_flag()
checks hdev-&gt;dev_flags instead of hdev-&gt;flags. HCI_INQUIRY is a bit that's
set on hdev-&gt;flags, not on hdev-&gt;dev_flags though.

HCI_INQUIRY equals the integer 7, and in hdev-&gt;dev_flags, 7 means
HCI_BONDABLE, so we were actually checking for HCI_BONDABLE here.

The mistake is only present in the synchronous code for starting an inquiry,
not in the async one. Also devices are typically bondable while doing an
inquiry, so that might be the reason why nobody noticed it so far.

Fixes: abfeea476c68 ("Bluetooth: hci_sync: Convert MGMT_OP_START_DISCOVERY")
Signed-off-by: Jonas Dreßler &lt;verdre@v0yd.nl&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: L2CAP: Fix possible multiple reject send</title>
<updated>2024-02-05T20:16:56+00:00</updated>
<author>
<name>Frédéric Danis</name>
<email>frederic.danis@collabora.com</email>
</author>
<published>2023-12-19T08:10:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d136385406676ff6f9021762bd66d6b387c5cf3e'/>
<id>d136385406676ff6f9021762bd66d6b387c5cf3e</id>
<content type='text'>
[ Upstream commit 96a3398b467ab8aada3df2f3a79f4b7835d068b8 ]

In case of an incomplete command or a command with a null identifier 2
reject packets will be sent, one with the identifier and one with 0.
Consuming the data of the command will prevent it.
This allows to send a reject packet for each corrupted command in a
multi-command packet.

Signed-off-by: Frédéric Danis &lt;frederic.danis@collabora.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 96a3398b467ab8aada3df2f3a79f4b7835d068b8 ]

In case of an incomplete command or a command with a null identifier 2
reject packets will be sent, one with the identifier and one with 0.
Consuming the data of the command will prevent it.
This allows to send a reject packet for each corrupted command in a
multi-command packet.

Signed-off-by: Frédéric Danis &lt;frederic.danis@collabora.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: hci_sync: fix BR/EDR wakeup bug</title>
<updated>2024-02-05T20:16:56+00:00</updated>
<author>
<name>clancy shang</name>
<email>clancy.shang@quectel.com</email>
</author>
<published>2023-12-18T10:24:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d5761e2f66b3ecea483147855935320590d22096'/>
<id>d5761e2f66b3ecea483147855935320590d22096</id>
<content type='text'>
[ Upstream commit d4b70ba1eab450eff9c5ef536f07c01d424b7eda ]

when Bluetooth set the event mask and enter suspend, the controller
has hci mode change event coming, it cause controller can not enter
sleep mode. so it should to set the hci mode change event mask before
enter suspend.

Signed-off-by: clancy shang &lt;clancy.shang@quectel.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 d4b70ba1eab450eff9c5ef536f07c01d424b7eda ]

when Bluetooth set the event mask and enter suspend, the controller
has hci mode change event coming, it cause controller can not enter
sleep mode. so it should to set the hci mode change event mask before
enter suspend.

Signed-off-by: clancy shang &lt;clancy.shang@quectel.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: ISO: Avoid creating child socket if PA sync is terminating</title>
<updated>2024-02-05T20:16:55+00:00</updated>
<author>
<name>Iulia Tanasescu</name>
<email>iulia.tanasescu@nxp.com</email>
</author>
<published>2023-12-05T16:11:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f291566ad1b10986ce5725ce9348a54e771e19ec'/>
<id>f291566ad1b10986ce5725ce9348a54e771e19ec</id>
<content type='text'>
[ Upstream commit 9f150019f176078144b02c4b9b9dbe7fd5a2fcc3 ]

When a PA sync socket is closed, the associated hcon is also unlinked
and cleaned up. If there are no other hcons marked with the
HCI_CONN_PA_SYNC flag, HCI_OP_LE_PA_TERM_SYNC is sent to controller.

Between the time of the command and the moment PA sync is terminated
in controller, residual BIGInfo reports might continue to come.
This causes a new PA sync hcon to be added, and a new socket to be
notified to user space.

This commit fixs this by adding a flag on a Broadcast listening
socket to mark when the PA sync child has been closed.

This flag is checked when BIGInfo reports are indicated in
iso_connect_ind, to avoid recreating a hcon and socket if
residual reports arrive before PA sync is terminated.

Signed-off-by: Iulia Tanasescu &lt;iulia.tanasescu@nxp.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.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 9f150019f176078144b02c4b9b9dbe7fd5a2fcc3 ]

When a PA sync socket is closed, the associated hcon is also unlinked
and cleaned up. If there are no other hcons marked with the
HCI_CONN_PA_SYNC flag, HCI_OP_LE_PA_TERM_SYNC is sent to controller.

Between the time of the command and the moment PA sync is terminated
in controller, residual BIGInfo reports might continue to come.
This causes a new PA sync hcon to be added, and a new socket to be
notified to user space.

This commit fixs this by adding a flag on a Broadcast listening
socket to mark when the PA sync child has been closed.

This flag is checked when BIGInfo reports are indicated in
iso_connect_ind, to avoid recreating a hcon and socket if
residual reports arrive before PA sync is terminated.

Signed-off-by: Iulia Tanasescu &lt;iulia.tanasescu@nxp.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Bluetooth: Fix atomicity violation in {min,max}_key_size_set</title>
<updated>2024-01-25T23:45:15+00:00</updated>
<author>
<name>Gui-Dong Han</name>
<email>2045gemini@gmail.com</email>
</author>
<published>2023-12-22T15:12:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d1c6a77d6d48215ba723f910eaabdb6e60d21a37'/>
<id>d1c6a77d6d48215ba723f910eaabdb6e60d21a37</id>
<content type='text'>
commit da9065caa594d19b26e1a030fd0cc27bd365d685 upstream.

In min_key_size_set():
    if (val &gt; hdev-&gt;le_max_key_size || val &lt; SMP_MIN_ENC_KEY_SIZE)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev-&gt;le_min_key_size = val;
    hci_dev_unlock(hdev);

In max_key_size_set():
    if (val &gt; SMP_MAX_ENC_KEY_SIZE || val &lt; hdev-&gt;le_min_key_size)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev-&gt;le_max_key_size = val;
    hci_dev_unlock(hdev);

The atomicity violation occurs due to concurrent execution of set_min and
set_max funcs.Consider a scenario where setmin writes a new, valid 'min'
value, and concurrently, setmax writes a value that is greater than the
old 'min' but smaller than the new 'min'. In this case, setmax might check
against the old 'min' value (before acquiring the lock) but write its
value after the 'min' has been updated by setmin. This leads to a
situation where the 'max' value ends up being smaller than the 'min'
value, which is an inconsistency.

This possible bug is found by an experimental static analysis tool
developed by our team, BassCheck[1]. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations. The above
possible bug is reported when our tool analyzes the source code of
Linux 5.17.

To resolve this issue, it is suggested to encompass the validity checks
within the locked sections in both set_min and set_max funcs. The
modification ensures that the validation of 'val' against the
current min/max values is atomic, thus maintaining the integrity of the
settings. With this patch applied, our tool no longer reports the bug,
with the kernel configuration allyesconfig for x86_64. Due to the lack of
associated hardware, we cannot test the patch in runtime testing, and just
verify it according to the code logic.

[1] https://sites.google.com/view/basscheck/

Fixes: 18f81241b74f ("Bluetooth: Move {min,max}_key_size debugfs ...")
Cc: stable@vger.kernel.org
Signed-off-by: Gui-Dong Han &lt;2045gemini@gmail.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&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 da9065caa594d19b26e1a030fd0cc27bd365d685 upstream.

In min_key_size_set():
    if (val &gt; hdev-&gt;le_max_key_size || val &lt; SMP_MIN_ENC_KEY_SIZE)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev-&gt;le_min_key_size = val;
    hci_dev_unlock(hdev);

In max_key_size_set():
    if (val &gt; SMP_MAX_ENC_KEY_SIZE || val &lt; hdev-&gt;le_min_key_size)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev-&gt;le_max_key_size = val;
    hci_dev_unlock(hdev);

The atomicity violation occurs due to concurrent execution of set_min and
set_max funcs.Consider a scenario where setmin writes a new, valid 'min'
value, and concurrently, setmax writes a value that is greater than the
old 'min' but smaller than the new 'min'. In this case, setmax might check
against the old 'min' value (before acquiring the lock) but write its
value after the 'min' has been updated by setmin. This leads to a
situation where the 'max' value ends up being smaller than the 'min'
value, which is an inconsistency.

This possible bug is found by an experimental static analysis tool
developed by our team, BassCheck[1]. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations. The above
possible bug is reported when our tool analyzes the source code of
Linux 5.17.

To resolve this issue, it is suggested to encompass the validity checks
within the locked sections in both set_min and set_max funcs. The
modification ensures that the validation of 'val' against the
current min/max values is atomic, thus maintaining the integrity of the
settings. With this patch applied, our tool no longer reports the bug,
with the kernel configuration allyesconfig for x86_64. Due to the lack of
associated hardware, we cannot test the patch in runtime testing, and just
verify it according to the code logic.

[1] https://sites.google.com/view/basscheck/

Fixes: 18f81241b74f ("Bluetooth: Move {min,max}_key_size debugfs ...")
Cc: stable@vger.kernel.org
Signed-off-by: Gui-Dong Han &lt;2045gemini@gmail.com&gt;
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
