linux-stable.git/net, branch v6.12.97

Bluetooth: L2CAP: fix tx ident leak for commands without a response

2026-07-24T14:11:56+00:00

commit 6e1930ece855a4c256f1c7e6632d634cfb9888b5 upstream.

Commit 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding
TX ident") changed ident allocation to use an IDA, releasing idents in
l2cap_put_ident() when the matching response command is received.

But identifiers allocated for commands that have no response defined
are never released. In particular L2CAP_LE_CREDITS is sent repeatedly for
the lifetime of an LE CoC channel, so a peer streaming data to the
host exhausts the 1-255 ident range after 254 credit packets. From
then on l2cap_get_ident() fails:

    kernel: Bluetooth: Unable to allocate ident: -28

and every subsequent L2CAP_LE_CREDITS packet is sent with ident 0,
which is invalid (Core Spec, Vol 3, Part A, Section 4: "Signaling
identifier 0x00 is an invalid identifier and shall never be used in
any command"). Remote stacks that validate the ident drop these
commands, never receive new credits, and the channel stalls
permanently. With default socket buffers this happens after roughly 0.5 MB
of received data (the exact amount depends on the socket receive buffer):

  < ACL Data TX: Handle 2048 flags 0x00 dlen 12
        LE L2CAP: LE Flow Control Credit (0x16) ident 0 len 4
          Source CID: 64
          Credits: 1

Release the ident immediately after sending L2CAP_LE_CREDITS since no
response will ever release it. Use a local variable instead of
chan->ident so that an ident that an EXT_FLOWCTL channel may be waiting on
(e.g. a pending reconfigure) is not overwritten by a credit packet.

Also add the missing L2CAP_LE_CONN_RSP case to l2cap_put_ident() so
idents allocated for outgoing L2CAP_LE_CONN_REQ commands are released
when the response arrives.

Fixes: 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221629
Assisted-by: Claude:claude-opus-4.8
Assisted-by: Fable:5
Signed-off-by: Stig Hornang 
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: 6lowpan: Fix using chan->conn as indication to no remote netdev

2026-07-24T14:11:56+00:00

commit d38eaf611839b85ade3dd3db309dbc8aaaaf0095 upstream.

b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding
conn ref") don't reset the chan->conn to NULL anymore making the bt#
netdev not be remove once the last l2cap_chan_del is removed.

Instead of restoring the original behavior this remove the logic of
keeping the interface after the last channel is removed because it
never worked as intended and the l2cap_chan_del always detach its
l2cap_conn which results in always removing the channel anyway.

Fixes: b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref")
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: L2CAP: Fix regressions caused by reusing ident

2026-07-24T14:11:56+00:00

commit 761fb8ec8778f0caf2bba5a41e3cff1ea86974f3 upstream.

This attempt to fix regressions caused by reusing ident which apparently
is not handled well on certain stacks causing the stack to not respond to
requests, so instead of simple returning the first unallocated id this
stores the last used tx_ident and then attempt to use the next until all
available ids are exausted and then cycle starting over to 1.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=221120
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221177
Fixes: 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident")
Signed-off-by: Luiz Augusto von Dentz 
Tested-by: Christian Eggers 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: hci_sync: Fix attempting to send HCI_Disconnect to BIS handle

2026-07-24T14:11:56+00:00

commit 314d30b1508682e27c8a324096262c66f23455d9 upstream.

BIS/PA connections do have their own cleanup proceedure which are
performed by hci_conn_cleanup/bis_cleanup.

Fixes: 23205562ffc8 ("Bluetooth: separate CIS_LINK and BIS_LINK link types")
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Greg Kroah-Hartman

dibs: loopback: validate offset and size in move_data()

2026-07-24T14:11:55+00:00

commit 78237e3c0720fcc6eb9b87e90fd70f63eeca886f upstream.

The loopback move_data() performs a memcpy into the registered DMB
without checking whether offset + size exceeds the DMB length.  Unlike
real ISM hardware, which enforces memory region bounds natively, the
software loopback has no such protection.

A peer-supplied out-of-bounds offset or oversized write would result in
an OOB write past the allocated kernel buffer.  Add an explicit bounds
check before the memcpy to reject such requests with -EINVAL.

Fixes: f7a22071dbf3 ("net/smc: implement DMB-related operations of loopback-ism")
Cc: stable@vger.kernel.org
Reported-by: Federico Kirschbaum 
Signed-off-by: Dust Li 
Reported-by: Baul Lee 
Link: https://patch.msgid.link/20260707074318.1448662-1-dust.li@linux.alibaba.com
Signed-off-by: Paolo Abeni 
[backport for smc_loopback instead of dibs_loopback]
Signed-off-by: Dust Li 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

2026-07-24T14:11:50+00:00

[ Upstream commit 6fef032af0092ed5ccb767239a9ac1bc38c08a40 ]

l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after
release_sock(parent). Once the parent lock is dropped the newly
enqueued child socket sk is reachable via the accept queue, so another
task can accept and free it before the callback dereferences sk,
resulting in a use-after-free.

Rework the ->new_connection() op so the core, rather than the callback,
owns the child channel's lifetime. The op now receives a pre-allocated
new_chan and returns an errno instead of allocating and returning a
channel. l2cap_new_connection() allocates the child channel and links
it into the conn list via __l2cap_chan_add() before invoking the
callback, so the conn-list reference keeps the channel alive once
release_sock(parent) exposes the socket to other tasks.

Channel configuration that was duplicated in l2cap_sock_init() and the
various new_connection callbacks is consolidated into
l2cap_chan_set_defaults(), which now inherits from the parent channel
when one is supplied.

Fixes: 8ffb929098a5 ("Bluetooth: Remove parent socket usage from l2cap_core.c")
Cc: stable@kernel.org
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Siwei Zhang 
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: 6lowpan: fix cyclic locking warning on netdev unregister

2026-07-24T14:11:50+00:00

[ Upstream commit 9707a015fe8f3ba8ec7c270f3b2b8efb38823d6b ]

6lowpan.c has theoretically conflicting lock orderings, which lockdep
complains about:

    a) rtnl_lock > hdev->workqueue

    from 6lowpan.c:delete_netdev -> rtnl_lock -> device_del
    -> put_device(parent) -> hci_release_dev -> destroy_workqueue

    b) hdev->workqueue > l2cap_conn->lock > chan->lock > rtnl_lock

    from hci_rx_work -> 6lowpan.c:chan_ready_cb
    -> lowpan_register_netdev, ifup -> rtnl_lock

Actual deadlock appears not possible, as hci_rx_work is disabled and
l2cap_conn flushed already on hdev unregister. Hence, do minimal thing
to make lockdep happy by breaking chain a) by holding hdev refcount
until after netdev put in 6lowpan.c.

Fixes the lockdep complaint:
WARNING: possible circular locking dependency detected.
kworker/0:1/11 is trying to acquire lock:
ffff8880023b3940 ((wq_completion)hci0#2){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x8b/0x130
but task is already holding lock:
ffffffff95e4f9c0 (rtnl_mutex){+.+.}-{4:4}, at: lowpan_unregister_netdev+0xd/0x30
Workqueue: events delete_netdev

Signed-off-by: Pauli Virtanen 
Signed-off-by: Luiz Augusto von Dentz 
Stable-dep-of: 6fef032af009 ("Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()

2026-07-24T14:11:50+00:00

[ Upstream commit 12917f591cea1af36087dba5b9ec888652f0b42a ]

hci_abort_conn() read hci_skb_event(hdev->sent_cmd) when a connection
was pending, but hdev->sent_cmd can be NULL while req_status is still
HCI_REQ_PEND, leading to a NULL pointer dereference and a general
protection fault from the hci_rx_work() receive path.

Instead of inspecting hdev->sent_cmd, track the in-flight create
connection command with a new per-connection HCI_CONN_CREATE flag and
route all cancellation through hci_cancel_connect_sync(), which
dispatches to a dedicated per-type cancel function. The create command
is in exactly one of two states: still queued, or in flight. The cancel
function holds cmd_sync_work_lock across the whole decision: the worker
takes this lock to dequeue every entry, so while it is held a queued
command cannot start running and an in-flight command cannot complete
and let the next command become pending. This keeps the flag test and
hci_cmd_sync_cancel() atomic with respect to the worker, so a queued
command is simply dequeued, and an in-flight command owned by this
connection is cancelled without the risk of cancelling an unrelated
command that became pending in the meantime. CIS uses the same flag
mechanism via HCI_CONN_CREATE_CIS but cannot be dequeued per-connection.

hci_acl_create_conn_sync() and hci_le_create_conn_sync() clear
HCI_CONN_CREATE after the create command completes, but the command
status handler can free conn via hci_conn_del() (for example when the
controller rejects the connection) while the worker is still blocked on
the connection complete event. Hold a reference on conn across the
create command so the flag can be cleared without a use-after-free.

Fixes: a13f316e90fd ("Bluetooth: hci_conn: Consolidate code for aborting connections")
Cc: stable@vger.kernel.org
Suggested-by: XIAO WU 
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Siwei Zhang 
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: separate CIS_LINK and BIS_LINK link types

2026-07-24T14:11:50+00:00

[ Upstream commit 23205562ffc8de20f57afdd984858cab29e77968 ]

Use separate link type id for unicast and broadcast ISO connections.
These connection types are handled with separate HCI commands, socket
API is different, and hci_conn has union fields that are different in
the two cases, so they shall not be mixed up.

Currently in most places it is attempted to distinguish ucast by
bacmp(&c->dst, BDADDR_ANY) but it is wrong as dst is set for bcast sink
hci_conn in iso_conn_ready(). Additionally checking sync_handle might be
OK, but depends on details of bcast conn configuration flow.

To avoid complicating it, use separate link types.

Fixes: f764a6c2c1e4 ("Bluetooth: ISO: Add broadcast support")
Signed-off-by: Pauli Virtanen 
Signed-off-by: Luiz Augusto von Dentz 
Stable-dep-of: 12917f591cea ("Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: hci_core: Enable buffer flow control for SCO/eSCO

2026-07-24T14:11:50+00:00

[ Upstream commit 13218453521d75916dfed55efb8e809bfc03cb4b ]

This enables buffer flow control for SCO/eSCO
(see: Bluetooth Core 6.0 spec: 6.22. Synchronous Flow Control Enable),
recently this has caused the following problem and is actually a nice
addition for the likes of Socket TX complete:

< HCI Command: Read Buffer Size (0x04|0x0005) plen 0
> HCI Event: Command Complete (0x0e) plen 11
      Read Buffer Size (0x04|0x0005) ncmd 1
        Status: Success (0x00)
        ACL MTU: 1021 ACL max packet: 5
        SCO MTU: 240  SCO max packet: 8
...
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
< SCO Data TX: Handle 257 flags 0x00 dlen 120
> HCI Event: Hardware Error (0x10) plen 1
        Code: 0x0a

To fix the code will now attempt to enable buffer flow control when
HCI_QUIRK_SYNC_FLOWCTL_SUPPORTED is set by the driver:

< HCI Command: Write Sync Fl.. (0x03|0x002f) plen 1
        Flow control: Enabled (0x01)
> HCI Event: Command Complete (0x0e) plen 4
      Write Sync Flow Control Enable (0x03|0x002f) ncmd 1
        Status: Success (0x00)

On success then HCI_SCO_FLOWCTL would be set which indicates sco_cnt
shall be used for flow contro.

Fixes: 7fedd3bb6b77 ("Bluetooth: Prioritize SCO traffic")
Signed-off-by: Luiz Augusto von Dentz 
Tested-by: Pauli Virtanen 
Stable-dep-of: 12917f591cea ("Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman