l2cap_le_connect_rsp() obtains a channel via
__l2cap_get_chan_by_ident() but neither holds a reference nor uses
l2cap_chan_hold_unless_zero() before locking and operating on it.
A concurrent l2cap_chan_del() triggered by a remote disconnect can
free the channel between the lookup and l2cap_chan_lock(), causing
a use-after-free.
The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler
l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero()
to safely hold a reference, but l2cap_le_connect_rsp() was left
unprotected.
Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup
and l2cap_chan_put() on the exit path, consistent with other L2CAP
response handlers.
Fixes: f1496dee9c ("Bluetooth: Add initial code for LE L2CAP Connect Request")
Assisted-by: Claude:deepseek-v4-pro
Signed-off-by: Jiale Yao <yaojiale02@163.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Commit 6c3ea155e5 ("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: 6c3ea155e5 ("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 <stig@hornang.me>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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: 8ffb929098 ("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 <oss@fourdim.xyz>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
get_l2cap_conn() looks up an LE hci_conn under hdev protection, but
then drops that protection before reading hcon->l2cap_data and before
lowpan_control_write() later dereferences conn->hcon. A disconnect or
device close can tear down the same L2CAP connection in that window.
The buggy scenario involves two paths, with each column showing the order
within that path:
6LoWPAN control write: HCI disconnect/device close:
1. get_l2cap_conn() finds hcon 1. hci_disconn_cfm() dispatches
and hcon->l2cap_data. the L2CAP disconnect callback.
2. get_l2cap_conn() drops hdev 2. l2cap_conn_del() clears
protection and returns conn. hcon->l2cap_data and drops the
L2CAP connection reference.
3. lowpan_control_write() reads 3. hci_conn_del() removes and drops
conn->hcon. the HCI connection.
Take a reference to the L2CAP connection with
l2cap_conn_hold_unless_zero() while hdev is still locked, and drop that
reference after the debugfs command's last use of conn. This mirrors the
existing L2CAP ACL receive-side handoff and keeps the connection
dereferenceable after leaving hdev protection. Export the existing helper
so the bluetooth_6lowpan module can use the same lifetime primitive.
Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in lowpan_control_write+0x374/0x520
The buggy address belongs to the object at ffff888111b9d000 which belongs
to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of freed 1024-byte region
[ffff888111b9d000, ffff888111b9d400)
Read of size 8
Call trace:
dump_stack_lvl+0x66/0xa0
print_report+0xce/0x5f0
lowpan_control_write+0x374/0x520 (net/bluetooth/6lowpan.c:1131)
srso_alias_return_thunk+0x5/0xfbef5
__virt_addr_valid+0x19f/0x330
kasan_report+0xe0/0x110
__debugfs_file_get+0xf7/0x400
full_proxy_write+0x9e/0xd0
vfs_write+0x1b0/0x810
ksys_write+0xd2/0x170
dnotify_flush+0x32/0x220
do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Allocated by task stack:
kasan_save_stack+0x33/0x60
kasan_save_track+0x17/0x60
__kasan_kmalloc+0xaa/0xb0
l2cap_conn_add+0x45/0x520
l2cap_chan_connect+0xac6/0xd90
l2cap_sock_connect+0x216/0x350
__sys_connect+0x101/0x130
__x64_sys_connect+0x40/0x50
do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task stack:
kasan_save_stack+0x33/0x60
kasan_save_track+0x17/0x60
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x5f/0x80
kfree+0x313/0x590
hci_conn_hash_flush+0xc0/0x140
hci_dev_close_sync+0x41a/0xb00
hci_dev_close+0x12f/0x160
hci_sock_ioctl+0x157/0x570
sock_do_ioctl+0xf7/0x210
sock_ioctl+0x32f/0x490
__x64_sys_ioctl+0xc7/0x110
do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
entry_SYSCALL_64_after_hwframe+0x77/0x7f
kasan_record_aux_stack+0xa7/0xc0
insert_work+0x32/0x100
__queue_work+0x262/0xa60
queue_work_on+0xad/0xb0
l2cap_connect_cfm+0x4ef/0x670
hci_le_remote_feat_complete_evt+0x247/0x430
hci_event_packet+0x360/0x6f0
hci_rx_work+0x2ae/0x7a0
process_one_work+0x4fd/0xbc0
worker_thread+0x2d8/0x570
kthread+0x1ad/0x1f0
ret_from_fork+0x3c9/0x540
ret_from_fork_asm+0x1a/0x30
Fixes: 6b8d4a6a03 ("Bluetooth: 6LoWPAN: Use connected oriented channel instead of fixed one")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_get_conf_opt() derives the option length from the
attacker-controlled opt->len field and immediately dereferences
opt->val (as u8, get_unaligned_le16() or get_unaligned_le32(), or a
raw pointer for the default case) before any caller has confirmed
that opt->len bytes are present in the buffer. The callers
(l2cap_parse_conf_req(), l2cap_parse_conf_rsp() and
l2cap_conf_rfc_get()) only detect a malformed option afterwards, once
the running length has gone negative, by which point the
out-of-bounds read has already executed.
An existing post-hoc length check keeps the garbage value from being
consumed, so this is not a data leak in the current control flow. It
is still a validate-after-use ordering bug: up to 4 bytes are read
past the end of the buffer before it is known to contain them, and it
is fragile to future changes in the callers.
Fix it at the source. Pass the end of the buffer into
l2cap_get_conf_opt() and refuse to touch opt->val unless the full
option (header + value) fits. Each caller computes an end pointer
once before the loop and checks the return value directly instead of
inferring the error from a negative length.
Fixes: 7c9cbd0b5e ("Bluetooth: Verify that l2cap_get_conf_opt provides large enough buffer")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for
pending_rx_work. process_pending_rx() takes the same mutex, so teardown
can deadlock against the worker it is flushing.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the l2cap_conn_ready() -> queue_work(...,
&conn->pending_rx_work) submit path, the l2cap_conn_del() ->
cancel_work_sync(&conn->pending_rx_work) teardown path, and the
process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep
reported:
WARNING: possible circular locking dependency detected
process_pending_rx+0x21/0x2a [vuln_msv]
l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]
*** DEADLOCK ***
Cancel pending_rx_work before taking conn->lock, matching the existing
lock-before-drain ordering used for the two delayed works in the same
teardown path. The pending_rx queue is still purged after the work has
been cancelled and conn->lock has been acquired.
Fixes: 7ab56c3a6e ("Bluetooth: Fix deadlock in l2cap_conn_del()")
Cc: stable@vger.kernel.org
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Connectionless L2CAP frames carry a two-byte PSM at the start of the
payload. l2cap_recv_frame() currently reads that PSM unconditionally
after validating only the outer L2CAP length.
A malformed connectionless frame with a zero- or one-byte payload can
therefore make the parser read beyond the advertised skb payload and use
tailroom bytes as part of the PSM. A VHCI-backed QEMU reproducer
injected a one-byte connectionless payload and reached the unchecked
read.
Reject connectionless frames that cannot contain the PSM before reading
or pulling it. This preserves all valid connectionless frames while
dropping only structurally incomplete packets.
Assisted-by: Codex:gpt-5.5-cyber-preview
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_chan_timeout() runs asynchronously and accesses chan->conn. If
the connection is torn down while the timer is running or pending,
chan->conn can be freed, leading to a use-after-free when the timer
worker attempts to lock conn->lock:
| BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
| BUG: KASAN: slab-use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]
| BUG: KASAN: slab-use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]
| BUG: KASAN: slab-use-after-free in mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318
| Write of size 8 at addr ffff8881298d9550 by task kworker/2:1/83
|
| CPU: 2 UID: 0 PID: 83 Comm: kworker/2:1 Not tainted 7.1.0-rc6-next-20260601-dirty #6 PREEMPT(full)
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
| Workqueue: events l2cap_chan_timeout
| Call Trace:
| <TASK>
| instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
| atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]
| __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]
| mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318
| l2cap_chan_timeout+0x5d/0x1b0 net/bluetooth/l2cap_core.c:422
| process_one_work kernel/workqueue.c:3326 [inline]
| process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409
| worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490
| kthread+0x346/0x430 kernel/kthread.c:436
| ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
| </TASK>
|
| Allocated by task 320:
| l2cap_conn_add+0xa7/0x820 net/bluetooth/l2cap_core.c:7075
| l2cap_connect_cfm+0xdb/0xd70 net/bluetooth/l2cap_core.c:7452
| hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
| hci_remote_features_evt+0x52f/0x9f0 net/bluetooth/hci_event.c:3760
| hci_event_func net/bluetooth/hci_event.c:7796 [inline]
| hci_event_packet+0x561/0xa70 net/bluetooth/hci_event.c:7847
| hci_rx_work+0x370/0x890 net/bluetooth/hci_core.c:4040
| process_one_work kernel/workqueue.c:3326 [inline]
| process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409
| worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490
| kthread+0x346/0x430 kernel/kthread.c:436
| ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
|
| Freed by task 322:
| hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
| hci_conn_hash_flush+0x101/0x1f0 net/bluetooth/hci_conn.c:2736
| hci_dev_close_sync+0x889/0xde0 net/bluetooth/hci_sync.c:5405
| hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]
| hci_unregister_dev+0x1f7/0x370 net/bluetooth/hci_core.c:2679
| vhci_release+0x12a/0x180 drivers/bluetooth/hci_vhci.c:690
| __fput+0x369/0x890 fs/file_table.c:510
| task_work_run+0x160/0x1d0 kernel/task_work.c:233
| get_signal+0xf5b/0x1120 kernel/signal.c:2810
| arch_do_signal_or_restart+0x4d/0x600 arch/x86/kernel/signal.c:337
| __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
| exit_to_user_mode_loop+0x85/0x510 kernel/entry/common.c:98
| do_syscall_64+0x263/0x3d0 arch/x86/entry/syscall_64.c:100
| entry_SYSCALL_64_after_hwframe+0x77/0x7f
|
| The buggy address belongs to the object at ffff8881298d9400
| which belongs to the cache kmalloc-512 of size 512
| The buggy address is located 336 bytes inside of
| freed 512-byte region [ffff8881298d9400, ffff8881298d9600)
Fix it by having chan->conn hold a reference to l2cap_conn (via
l2cap_conn_get) when the channel is added to the connection, and
releasing it in the channel destructor. This ensures the l2cap_conn
remains alive as long as the channel exists.
A new FLAG_DEL channel flag is introduced to indicate that the channel
has been deleted from its connection. l2cap_chan_del() atomically sets
this flag using test_and_set_bit() instead of setting chan->conn to
NULL. All asynchronous workers (l2cap_chan_timeout, l2cap_ack_timeout,
l2cap_monitor_timeout, l2cap_retrans_timeout) and l2cap_chan_send()
check FLAG_DEL to determine whether the channel has been torn down,
rather than testing chan->conn for NULL.
Fixes: 8c8e620467 ("Bluetooth: L2CAP: use chan timer to close channels in cleanup_listen()")
Cc: <stable@vger.kernel.org>
Cc: Siwei Zhang <oss@fourdim.xyz>
Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Assisted-by: Gemini:gemini-3.1-pro-preview
Reported-by: https://sashiko.dev/#/patchset/20260521021249.3258069-1-oss%40fourdim.xyz
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Many bluetooth source files are missing SPDX-License-Identifier
lines. Add appropriate IDs to these files, and remove other
license lines from the headers.
Leave the warranty disclaimer in files where the license ID is
GPL-2.0 but the wording of the disclaimer is slightly different
from that of the GPL v2 disclaimer.
It is not different enough to cause licensing conflicts, but is
kept to honor the original contributors' legal intent.
Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
net/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR
signaling packets up to the channel MTU and dispatches each command
without enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer
within radio range can send a fixed-channel CID 0x0001 packet that is
larger than MTUsig and contains many L2CAP_ECHO_REQ commands before
pairing. In a real-radio stock-kernel run, one 681-byte signaling
packet containing 168 zero-length ECHO_REQ commands made the target
transmit 168 ECHO_RSP frames over about 220 ms.
Impact: a Bluetooth BR/EDR peer within radio range, before pairing, can
force 168 ECHO_RSP frames from one 681-byte fixed-channel signaling
packet containing packed ECHO_REQ commands.
Define Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and
reject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP
carrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched.
The Bluetooth Core spec wording for MTUExceeded says the reject
identifier shall match the first request command in the packet, and
that packets containing only responses shall be silently discarded.
Linux intentionally deviates from that prescription: silently
discarding desynchronizes the peer because the remote stack never
learns its responses were dropped, and locating the first request
command requires walking command headers past MTUsig, i.e. processing
bytes from a packet we have already decided is too large to process.
We therefore always emit one reject and use the identifier from the
first command header, a single fixed-offset byte read.
The unrestricted BR/EDR signaling parser and ECHO_REQ response path both
trace to the initial git import; no later introducing commit is
available for a Fixes tag.
Cc: stable@vger.kernel.org
Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Link: https://lore.kernel.org/r/20260518002800.1361430-1-michael.bommarito@gmail.com
Link: https://lore.kernel.org/r/20260520135034.1060859-1-michael.bommarito@gmail.com
Link: https://lore.kernel.org/r/20260521000555.3712030-1-michael.bommarito@gmail.com
Assisted-by: Claude:claude-opus-4-7
Assisted-by: Codex:gpt-5-5-xhigh
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
If dcid is received for an already-assigned destination CID the spec
requires that both channels to be discarded, but calling l2cap_chan_del
may invalidate the tmp cursor created by list_for_each_entry_safe and
in fact it is the wrong procedure as the chan->dcid may be assigned
previously it really needs to be disconnected.
Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so
instead schedule l2cap_chan_timeout with delay 0 to close the channel
asynchronously.
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_ecred_reconf_rsp() returns early on success without clearing
chan->ident. Every other L2CAP response handler (l2cap_ecred_conn_rsp,
l2cap_le_connect_rsp, l2cap_config_rsp) clears chan->ident after a
successful transaction to prevent the channel from matching subsequent
responses with the recycled ident value.
A remote attacker that completed a reconfiguration as the peer can
replay a failure response with the stale ident, causing the kernel to
match and destroy the already-established channel via
l2cap_chan_del(chan, ECONNRESET).
Clear chan->ident for all matching channels on success, and harden the
failure path by using l2cap_chan_hold_unless_zero() consistent with
other L2CAP handlers (l2cap_le_command_rej, __l2cap_get_chan_by_ident).
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Zhenghang Xiao <kipreyyy@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
__set_chan_timer() takes a l2cap_chan reference via l2cap_chan_hold()
before scheduling the delayed work. The normal path in
l2cap_chan_timeout() drops this reference with l2cap_chan_put() at the
end, but the early return when chan->conn is NULL skips the put,
leaking the reference.
Add the missing l2cap_chan_put() before the early return.
Fixes: adf0398cee ("Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout")
Cc: stable@vger.kernel.org
Signed-off-by: Siwei Zhang <oss@fourdim.xyz>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Commit 1c08108f30 ("Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end
warnings") converted the on-stack request PDU in l2cap_ecred_reconfigure()
from an explicit packed struct to DEFINE_RAW_FLEX(), but did not adjust the
size and source-pointer arguments to l2cap_send_cmd():
- struct {
- struct l2cap_ecred_reconf_req req;
- __le16 scid;
- } pdu;
+ DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
...
l2cap_send_cmd(conn, chan->ident, L2CAP_ECRED_RECONF_REQ,
sizeof(pdu), &pdu);
After the conversion, DEFINE_RAW_FLEX() expands to declare an anonymous
union pdu_u plus a local pointer "pdu" pointing at it. Therefore:
- sizeof(pdu) is now sizeof(struct l2cap_ecred_reconf_req *) = 8 on
64-bit (4 on 32-bit), not the 6 bytes of (mtu, mps, scid[1]).
- &pdu is the address of the local pointer's stack storage, not the
address of the request payload.
l2cap_send_cmd() forwards (data, count) to l2cap_build_cmd(), which calls
skb_put_data(skb, data, count). The L2CAP_ECRED_RECONFIGURE_REQ packet
body therefore contains 8 bytes copied from the kernel stack starting at
&pdu -- the 8 bytes overlap the pdu pointer's value, leaking a kernel
stack address to the paired Bluetooth peer. The intended (mtu, mps, scid)
fields are not transmitted at all, so the peer rejects the request as
malformed and the L2CAP_ECRED_RECONFIGURE feature itself has been broken
for the local-side initiator since the introducing commit landed.
The sibling site l2cap_ecred_conn_req() in the same commit was converted
correctly (sizeof(*pdu) + len, pdu); only this site was missed.
Restore the original semantics: pass the full flex-struct size via
struct_size(pdu, scid, 1) and the pdu pointer (the struct address) as
the source.
Validated on a stock 7.0-based host kernel via the real call path:
setsockopt(SOL_BLUETOOTH, BT_RCVMTU, ...) on a BT_CONNECTED
L2CAP_MODE_EXT_FLOWCTL socket emits an L2CAP_ECRED_RECONFIGURE_REQ
whose body is 8 bytes (the on-stack pdu local's value) rather than
the expected 6. Three captures from fresh socket / fresh hciemu peer
on the same host -- low bytes vary per call, high 0xffff confirms a
kernel virtual address (KASLR-randomised stack slot, not a fixed
string):
RECONF_REQ body (ident=0x02 len=8): 42 fb 54 af 0e ca ff ff
RECONF_REQ body (ident=0x02 len=8): 52 3d 2e af 0e ca ff ff
RECONF_REQ body (ident=0x02 len=8): b2 fc 5b af 0e ca ff ff
After this patch the body is 6 bytes carrying the expected
little-endian (mtu, mps, scid).
Cc: stable@vger.kernel.org
Fixes: 1c08108f30 ("Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings")
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
When a BLE peripheral sends an L2CAP Connection Parameter Update Request
the processing path is:
process_pending_rx() [takes conn->lock]
l2cap_le_sig_channel()
l2cap_conn_param_update_req()
hci_le_conn_update() [takes hdev->lock]
Meanwhile other code paths take the locks in the opposite order:
l2cap_chan_connect() [takes hdev->lock]
...
mutex_lock(&conn->lock)
l2cap_conn_ready() [hdev->lock via hci_cb_list_lock]
...
mutex_lock(&conn->lock)
This is a classic AB/BA deadlock which lockdep reports as a circular
locking dependency when connecting a BLE MIDI keyboard (Carry-On FC-49).
Fix this by making hci_le_conn_update() defer the HCI command through
hci_cmd_sync_queue() so it no longer needs to take hdev->lock in the
caller context. The sync callback uses __hci_cmd_sync_status_sk() to
wait for the HCI_EV_LE_CONN_UPDATE_COMPLETE event, then updates the
stored connection parameters (hci_conn_params) and notifies userspace
(mgmt_new_conn_param) only after the controller has confirmed the update.
A reference on hci_conn is held via hci_conn_get()/hci_conn_put() for
the lifetime of the queued work to prevent use-after-free, and
hci_conn_valid() is checked before proceeding in case the connection was
removed while the work was pending. The hci_dev_lock is held across
hci_conn_valid() and all conn field accesses to prevent a concurrent
disconnect from invalidating the connection mid-use.
Fixes: f044eb0524 ("Bluetooth: Store latency and supervision timeout in connection params")
Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
The L2CAP specification states that if more than one channel is being
reconfigured, the MPS shall not be decreased. The current check has
two issues:
1) The comparison uses >= (greater-than-or-equal), which incorrectly
rejects reconfiguration requests where the MPS stays the same.
Since the spec says MPS "shall be greater than or equal to the
current MPS", only a strict decrease (remote_mps > mps) should be
rejected. Keeping the same MPS is valid.
2) The multi-channel guard uses `&& i` (loop index) to approximate
"more than one channel", but this incorrectly allows MPS decrease
for the first channel (i==0) even when multiple channels are being
reconfigured. Replace with `&& num_scid > 1` which correctly
checks whether the request covers more than one channel.
Fixes: 7accb1c432 ("Bluetooth: L2CAP: Fix invalid response to L2CAP_ECRED_RECONF_REQ")
Signed-off-by: Dudu Lu <phx0fer@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_ecred_reconf_rsp() calls l2cap_chan_del() without holding
l2cap_chan_lock(). Every other l2cap_chan_del() caller in the file
acquires the lock first. A remote BLE device can send a crafted
L2CAP ECRED reconfiguration response to corrupt the channel list
while another thread is iterating it.
Add l2cap_chan_hold() and l2cap_chan_lock() before l2cap_chan_del(),
and l2cap_chan_unlock() and l2cap_chan_put() after, matching the
pattern used in l2cap_ecred_conn_rsp() and l2cap_conn_del().
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Dudu Lu <phx0fer@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Core 6.0, Vol 3, Part A, 3.4.3:
"... If the payload size of any K-frame exceeds the receiver's MPS, the
receiver shall disconnect the channel..."
This fixes L2CAP/LE/CFC/BV-27-C (running together with 'l2test -r -P
0x0027 -V le_public -I 100').
Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Christian Eggers <ceggers@arri.de>
l2cap_config_req() processes CONFIG_REQ for channels in BT_CONNECTED
state to support L2CAP reconfiguration (e.g. MTU changes). However,
since both CONF_INPUT_DONE and CONF_OUTPUT_DONE are already set from
the initial configuration, the reconfiguration path falls through to
l2cap_ertm_init(), which re-initializes tx_q, srej_q, srej_list, and
retrans_list without freeing the previous allocations and sets
chan->sdu to NULL without freeing the existing skb. This leaks all
previously allocated ERTM resources.
Additionally, l2cap_parse_conf_req() does not validate the minimum
value of remote_mps derived from the RFC max_pdu_size option. A zero
value propagates to l2cap_segment_sdu() where pdu_len becomes zero,
causing the while loop to never terminate since len is never
decremented, exhausting all available memory.
Fix the double-init by skipping l2cap_ertm_init() and
l2cap_chan_ready() when the channel is already in BT_CONNECTED state,
while still allowing the reconfiguration parameters to be updated
through l2cap_parse_conf_req(). Also add a pdu_len zero check in
l2cap_segment_sdu() as a safeguard.
Fixes: 96298f6401 ("Bluetooth: L2CAP: handle l2cap config request during open state")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_conn_del() calls cancel_delayed_work_sync() for both info_timer
and id_addr_timer while holding conn->lock. However, the work functions
l2cap_info_timeout() and l2cap_conn_update_id_addr() both acquire
conn->lock, creating a potential AB-BA deadlock if the work is already
executing when l2cap_conn_del() takes the lock.
Move the work cancellations before acquiring conn->lock and use
disable_delayed_work_sync() to additionally prevent the works from
being rearmed after cancellation, consistent with the pattern used in
hci_conn_del().
Fixes: ab4eedb790 ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
When the L2CAP channel mode is L2CAP_MODE_ERTM/L2CAP_MODE_STREAMING,
l2cap_publish_rx_avail will be called and le flow credits will be sent in
l2cap_chan_rx_avail, even though the link type is ACL.
The logs in question as follows:
> ACL Data RX: Handle 129 flags 0x02 dlen 12
L2CAP: Unknown (0x16) ident 4 len 4
40 00 ed 05
< ACL Data TX: Handle 129 flags 0x00 dlen 10
L2CAP: Command Reject (0x01) ident 4 len 2
Reason: Command not understood (0x0000)
Bluetooth: Unknown BR/EDR signaling command 0x16
Bluetooth: Wrong link type (-22)
Fixes: ce60b9231b ("Bluetooth: compute LE flow credits based on recvbuf space")
Signed-off-by: Zhang Chen <zhangchen01@kylinos.cn>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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: 6c3ea155e5 ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Christian Eggers <ceggers@arri.de>
l2cap_ecred_data_rcv() reads the SDU length field from skb->data using
get_unaligned_le16() without first verifying that skb contains at least
L2CAP_SDULEN_SIZE (2) bytes. When skb->len is less than 2, this reads
past the valid data in the skb.
The ERTM reassembly path correctly calls pskb_may_pull() before reading
the SDU length (l2cap_reassemble_sdu, L2CAP_SAR_START case). Apply the
same validation to the Enhanced Credit Based Flow Control data path.
Fixes: aac23bf636 ("Bluetooth: Implement LE L2CAP reassembly")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Syzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd()
that is triggered by a malformed Enhanced Credit Based Connection Request.
The vulnerability stems from l2cap_ecred_conn_req(). The function allocates
a local stack buffer (`pdu`) designed to hold a maximum of 5 Source Channel
IDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more
than 5 SCIDs, the function calculates `rsp_len` based on this unvalidated
`cmd_len` before checking if the number of SCIDs exceeds
L2CAP_ECRED_MAX_CID.
If the SCID count is too high, the function correctly jumps to the
`response` label to reject the packet, but `rsp_len` retains the
attacker's oversized value. Consequently, l2cap_send_cmd() is instructed
to read past the end of the 18-byte `pdu` buffer, triggering a
KASAN panic.
Fix this by moving the assignment of `rsp_len` to after the `num_scid`
boundary check. If the packet is rejected, `rsp_len` will safely
remain 0, and the error response will only read the 8-byte base header
from the stack.
Fixes: c28d2bff70 ("Bluetooth: L2CAP: Fix result of L2CAP_ECRED_CONN_RSP when MTU is too short")
Reported-by: syzbot+b7f3e7d9a596bf6a63e3@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b7f3e7d9a596bf6a63e3
Tested-by: syzbot+b7f3e7d9a596bf6a63e3@syzkaller.appspotmail.com
Signed-off-by: Minseo Park <jacob.park.9436@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_information_rsp() checks that cmd_len covers the fixed
l2cap_info_rsp header (type + result, 4 bytes) but then reads
rsp->data without verifying that the payload is present:
- L2CAP_IT_FEAT_MASK calls get_unaligned_le32(rsp->data), which reads
4 bytes past the header (needs cmd_len >= 8).
- L2CAP_IT_FIXED_CHAN reads rsp->data[0], 1 byte past the header
(needs cmd_len >= 5).
A truncated L2CAP_INFO_RSP with result == L2CAP_IR_SUCCESS triggers an
out-of-bounds read of adjacent skb data.
Guard each data access with the required payload length check. If the
payload is too short, skip the read and let the state machine complete
with safe defaults (feat_mask and remote_fixed_chan remain zero from
kzalloc), so the info timer cleanup and l2cap_conn_start() still run
and the connection is not stalled.
Fixes: 4e8402a3f8 ("[Bluetooth] Retrieve L2CAP features mask on connection setup")
Cc: stable@vger.kernel.org
Signed-off-by: Lukas Johannes Möller <research@johannes-moeller.dev>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_ecred_reconf_rsp() casts the incoming data to struct
l2cap_ecred_conn_rsp (the ECRED *connection* response, 8 bytes with
result at offset 6) instead of struct l2cap_ecred_reconf_rsp (2 bytes
with result at offset 0).
This causes two problems:
- The sizeof(*rsp) length check requires 8 bytes instead of the
correct 2, so valid L2CAP_ECRED_RECONF_RSP packets are rejected
with -EPROTO.
- rsp->result reads from offset 6 instead of offset 0, returning
wrong data when the packet is large enough to pass the check.
Fix by using the correct type. Also pass the already byte-swapped
result variable to BT_DBG instead of the raw __le16 field.
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Cc: stable@vger.kernel.org
Signed-off-by: Lukas Johannes Möller <research@johannes-moeller.dev>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Currently the code attempts to accept requests regardless of the
command identifier which may cause multiple requests to be marked
as pending (FLAG_DEFER_SETUP) which can cause more than
L2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer
causing an overflow.
The spec is quite clear that the same identifier shall not be used on
subsequent requests:
'Within each signaling channel a different Identifier shall be used
for each successive request or indication.'
https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d
So this attempts to check if there are any channels pending with the
same identifier and rejects if any are found.
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
After commit ab4eedb790 ("Bluetooth: L2CAP: Fix corrupted list in
hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to
conn->users. However, l2cap_register_user() and l2cap_unregister_user()
don't use conn->lock, creating a race condition where these functions can
access conn->users and conn->hchan concurrently with l2cap_conn_del().
This can lead to use-after-free and list corruption bugs, as reported
by syzbot.
Fix this by changing l2cap_register_user() and l2cap_unregister_user()
to use conn->lock instead of hci_dev_lock(), ensuring consistent locking
for the l2cap_conn structure.
Reported-by: syzbot+14b6d57fb728e27ce23c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=14b6d57fb728e27ce23c
Fixes: ab4eedb790 ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del")
Signed-off-by: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Core 6.0, Vol 3, Part A, 3.4.3:
"... If the sum of the payload sizes for the K-frames exceeds the
specified SDU length, the receiver shall disconnect the channel."
This fixes L2CAP/LE/CFC/BV-27-C (running together with 'l2test -r -P
0x0027 -V le_public').
Fixes: aac23bf636 ("Bluetooth: Implement LE L2CAP reassembly")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Core 6.0, Vol 3, Part A, 3.4.3:
"If the SDU length field value exceeds the receiver's MTU, the receiver
shall disconnect the channel..."
This fixes L2CAP/LE/CFC/BV-26-C (running together with 'l2test -r -P
0x0027 -V le_public -I 100').
Fixes: aac23bf636 ("Bluetooth: Implement LE L2CAP reassembly")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This adds a check for encryption key size upon receiving
L2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which
expects L2CAP_CR_LE_BAD_KEY_SIZE.
Link: https://lore.kernel.org/linux-bluetooth/5782243.rdbgypaU67@n9w6sw14/
Fixes: 27e2d4c8d2 ("Bluetooth: Add basic LE L2CAP connect request receiving support")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Christian Eggers <ceggers@arri.de>
Upon receiving L2CAP_ECRED_CONN_REQ the given MTU shall be checked
against the suggested MTU of the listening socket as that is required
by the likes of PTS L2CAP/ECFC/BV-27-C test which expects
L2CAP_CR_LE_UNACCEPT_PARAMS if the MTU is lowers than socket omtu.
In order to be able to set chan->omtu the code now allows setting
setsockopt(BT_SNDMTU), but it is only allowed when connection has not
been stablished since there is no procedure to reconfigure the output
MTU.
Link: https://github.com/bluez/bluez/issues/1895
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Similar to 03dba9cea7 ("Bluetooth: L2CAP: Fix not responding with
L2CAP_CR_LE_ENCRYPTION") the result code L2CAP_CR_LE_ENCRYPTION shall
be used when BT_SECURITY_MEDIUM is set since that means security mode 2
which mean it doesn't require authentication which results in
qualification test L2CAP/ECFC/BV-32-C failing.
Link: https://github.com/bluez/bluez/issues/1871
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Test L2CAP/ECFC/BV-26-C expect the response to L2CAP_ECRED_CONN_REQ with
and MTU value < L2CAP_ECRED_MIN_MTU (64) to be L2CAP_CR_LE_INVALID_PARAMS
rather than L2CAP_CR_LE_UNACCEPT_PARAMS.
Also fix not including the correct number of CIDs in the response since
the spec requires all CIDs being rejected to be included in the
response.
Link: https://github.com/bluez/bluez/issues/1868
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This fixes responding with an invalid result caused by checking the
wrong size of CID which should have been (cmd_len - sizeof(*req)) and
on top of it the wrong result was use L2CAP_CR_LE_INVALID_PARAMS which
is invalid/reserved for reconf when running test like L2CAP/ECFC/BI-03-C:
> ACL Data RX: Handle 64 flags 0x02 dlen 14
LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
MTU: 64
MPS: 64
Source CID: 64
< ACL Data TX: Handle 64 flags 0x00 dlen 10
LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
! Result: Reserved (0x000c)
Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003)
Fiix L2CAP/ECFC/BI-04-C which expects L2CAP_RECONF_INVALID_MPS (0x0002)
when more than one channel gets its MPS reduced:
> ACL Data RX: Handle 64 flags 0x02 dlen 16
LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 8
MTU: 264
MPS: 99
Source CID: 64
! Source CID: 65
< ACL Data TX: Handle 64 flags 0x00 dlen 10
LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
! Result: Reconfiguration successful (0x0000)
Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)
Fix L2CAP/ECFC/BI-05-C when SCID is invalid (85 unconnected):
> ACL Data RX: Handle 64 flags 0x02 dlen 14
LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
MTU: 65
MPS: 64
! Source CID: 85
< ACL Data TX: Handle 64 flags 0x00 dlen 10
LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
! Result: Reconfiguration successful (0x0000)
Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003)
Fix L2CAP/ECFC/BI-06-C when MPS < L2CAP_ECRED_MIN_MPS (64):
> ACL Data RX: Handle 64 flags 0x02 dlen 14
LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
MTU: 672
! MPS: 63
Source CID: 64
< ACL Data TX: Handle 64 flags 0x00 dlen 10
LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
! Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)
Result: Reconfiguration failed - other unacceptable parameters (0x0004)
Fix L2CAP/ECFC/BI-07-C when MPS reduced for more than one channel:
> ACL Data RX: Handle 64 flags 0x02 dlen 16
LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 3 len 8
MTU: 84
! MPS: 71
Source CID: 64
! Source CID: 65
< ACL Data TX: Handle 64 flags 0x00 dlen 10
LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
! Result: Reconfiguration successful (0x0000)
Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)
Link: https://github.com/bluez/bluez/issues/1865
Fixes: 15f02b9105 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
This attempts to proper track outstanding request by using struct ida
and allocating from it in l2cap_get_ident using ida_alloc_range which
would reuse ids as they are free, then upon completion release
the id using ida_free.
This fixes the qualification test case L2CAP/COS/CED/BI-29-C which
attempts to check if the host stack is able to work after 256 attempts
to connect which requires Ident field to use the full range of possible
values in order to pass the test.
Link: https://github.com/bluez/bluez/issues/1829
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't
ensure hci_conn* is not concurrently modified/deleted. This locking
appears to be leftover from before conn_hash started using RCU
commit bf4c632524 ("Bluetooth: convert conn hash to RCU")
and not clear if it had purpose since then.
Currently, there are code paths that delete hci_conn* from elsewhere
than the ordered hdev->workqueue where the RX work runs in. E.g.
commit 5af1f84ed1 ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync")
introduced some of these, and there probably were a few others before
it. It's better to do the locking so that even if these run
concurrently no UAF is possible.
Move the lookup of hci_conn and associated socket-specific conn to
protocol recv handlers, and do them within a single critical section
to cover hci_conn* usage and lookup.
syzkaller has reported a crash that appears to be this issue:
[Task hdev->workqueue] [Task 2]
hci_disconnect_all_sync
l2cap_recv_acldata(hcon)
hci_conn_get(hcon)
hci_abort_conn_sync(hcon)
hci_dev_lock
hci_dev_lock
hci_conn_del(hcon)
v-------------------------------- hci_dev_unlock
hci_conn_put(hcon)
conn = hcon->l2cap_data (UAF)
Fixes: 5af1f84ed1 ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync")
Reported-by: syzbot+d32d77220b92eddd89ad@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d32d77220b92eddd89ad
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_chan_put() is exported, so export also l2cap_chan_hold() for
modules.
l2cap_chan_hold() has use case in net/bluetooth/6lowpan.c
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This reverts commit c9d84da18d. It
replaces in L2CAP calls to msecs_to_jiffies() to secs_to_jiffies()
and updates the constants accordingly. But the constants are also
used in LCAP Configure Request and L2CAP Configure Response which
expect values in milliseconds.
This may prevent correct usage of L2CAP channel.
To fix it, keep those constants in milliseconds and so revert this
change.
Fixes: c9d84da18d ("Bluetooth: L2CAP: convert timeouts to secs_to_jiffies()")
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Configuration request only configure the incoming direction of the peer
initiating the request, so using the MTU is the other direction shall
not be used, that said the spec allows the peer responding to adjust:
Bluetooth Core 6.1, Vol 3, Part A, Section 4.5
'Each configuration parameter value (if any is present) in an
L2CAP_CONFIGURATION_RSP packet reflects an ‘adjustment’ to a
configuration parameter value that has been sent (or, in case of
default values, implied) in the corresponding
L2CAP_CONFIGURATION_REQ packet.'
That said adjusting the MTU in the response shall be limited to ERTM
channels only as for older modes the remote stack may not be able to
detect the adjustment causing it to silently drop packets.
Link: https://github.com/bluez/bluez/issues/1422
Link: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/149
Link: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4793
Fixes: 042bb9603c ("Bluetooth: L2CAP: Fix L2CAP MTU negotiation")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
OBEX download from iPhone is currently slow due to small packet size
used to transfer data which doesn't follow the MTU negotiated during
L2CAP connection, i.e. 672 bytes instead of 32767:
< ACL Data TX: Handle 11 flags 0x00 dlen 12
L2CAP: Connection Request (0x02) ident 18 len 4
PSM: 4103 (0x1007)
Source CID: 72
> ACL Data RX: Handle 11 flags 0x02 dlen 16
L2CAP: Connection Response (0x03) ident 18 len 8
Destination CID: 14608
Source CID: 72
Result: Connection successful (0x0000)
Status: No further information available (0x0000)
< ACL Data TX: Handle 11 flags 0x00 dlen 27
L2CAP: Configure Request (0x04) ident 20 len 19
Destination CID: 14608
Flags: 0x0000
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 32767
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 63
Max transmit: 3
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
> ACL Data RX: Handle 11 flags 0x02 dlen 26
L2CAP: Configure Request (0x04) ident 72 len 18
Destination CID: 72
Flags: 0x0000
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 32
Max transmit: 255
Retransmission timeout: 0
Monitor timeout: 0
Maximum PDU size: 65527
Option: Frame Check Sequence (0x05) [mandatory]
FCS: 16-bit FCS (0x01)
< ACL Data TX: Handle 11 flags 0x00 dlen 29
L2CAP: Configure Response (0x05) ident 72 len 21
Source CID: 14608
Flags: 0x0000
Result: Success (0x0000)
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 672
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 32
Max transmit: 255
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
> ACL Data RX: Handle 11 flags 0x02 dlen 32
L2CAP: Configure Response (0x05) ident 20 len 24
Source CID: 72
Flags: 0x0000
Result: Success (0x0000)
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 32767
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 63
Max transmit: 3
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
Option: Frame Check Sequence (0x05) [mandatory]
FCS: 16-bit FCS (0x01)
...
> ACL Data RX: Handle 11 flags 0x02 dlen 680
Channel: 72 len 676 ctrl 0x0202 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8}
I-frame: Unsegmented TxSeq 1 ReqSeq 2
< ACL Data TX: Handle 11 flags 0x00 dlen 13
Channel: 14608 len 9 ctrl 0x0204 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8}
I-frame: Unsegmented TxSeq 2 ReqSeq 2
> ACL Data RX: Handle 11 flags 0x02 dlen 680
Channel: 72 len 676 ctrl 0x0304 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8}
I-frame: Unsegmented TxSeq 2 ReqSeq 3
The MTUs are negotiated for each direction. In this traces 32767 for
iPhone->localhost and no MTU for localhost->iPhone, which based on
'4.4 L2CAP_CONFIGURATION_REQ' (Core specification v5.4, Vol. 3, Part
A):
The only parameters that should be included in the
L2CAP_CONFIGURATION_REQ packet are those that require different
values than the default or previously agreed values.
...
Any missing configuration parameters are assumed to have their
most recently explicitly or implicitly accepted values.
and '5.1 Maximum transmission unit (MTU)':
If the remote device sends a positive L2CAP_CONFIGURATION_RSP
packet it should include the actual MTU to be used on this channel
for traffic flowing into the local device.
...
The default value is 672 octets.
is set by BlueZ to 672 bytes.
It seems that the iPhone used the lowest negotiated value to transfer
data to the localhost instead of the negotiated one for the incoming
direction.
This could be fixed by using the MTU negotiated for the other
direction, if exists, in the L2CAP_CONFIGURATION_RSP.
This allows to use segmented packets as in the following traces:
< ACL Data TX: Handle 11 flags 0x00 dlen 12
L2CAP: Connection Request (0x02) ident 22 len 4
PSM: 4103 (0x1007)
Source CID: 72
< ACL Data TX: Handle 11 flags 0x00 dlen 27
L2CAP: Configure Request (0x04) ident 24 len 19
Destination CID: 2832
Flags: 0x0000
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 32767
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 63
Max transmit: 3
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
> ACL Data RX: Handle 11 flags 0x02 dlen 26
L2CAP: Configure Request (0x04) ident 15 len 18
Destination CID: 72
Flags: 0x0000
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 32
Max transmit: 255
Retransmission timeout: 0
Monitor timeout: 0
Maximum PDU size: 65527
Option: Frame Check Sequence (0x05) [mandatory]
FCS: 16-bit FCS (0x01)
< ACL Data TX: Handle 11 flags 0x00 dlen 29
L2CAP: Configure Response (0x05) ident 15 len 21
Source CID: 2832
Flags: 0x0000
Result: Success (0x0000)
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 32767
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 32
Max transmit: 255
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
> ACL Data RX: Handle 11 flags 0x02 dlen 32
L2CAP: Configure Response (0x05) ident 24 len 24
Source CID: 72
Flags: 0x0000
Result: Success (0x0000)
Option: Maximum Transmission Unit (0x01) [mandatory]
MTU: 32767
Option: Retransmission and Flow Control (0x04) [mandatory]
Mode: Enhanced Retransmission (0x03)
TX window size: 63
Max transmit: 3
Retransmission timeout: 2000
Monitor timeout: 12000
Maximum PDU size: 1009
Option: Frame Check Sequence (0x05) [mandatory]
FCS: 16-bit FCS (0x01)
...
> ACL Data RX: Handle 11 flags 0x02 dlen 1009
Channel: 72 len 1005 ctrl 0x4202 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8}
I-frame: Start (len 21884) TxSeq 1 ReqSeq 2
> ACL Data RX: Handle 11 flags 0x02 dlen 1009
Channel: 72 len 1005 ctrl 0xc204 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8}
I-frame: Continuation TxSeq 2 ReqSeq 2
This has been tested with kernel 5.4 and BlueZ 5.77.
Cc: stable@vger.kernel.org
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Depending on the security set the response to L2CAP_LE_CONN_REQ shall be
just L2CAP_CR_LE_ENCRYPTION if only encryption when BT_SECURITY_MEDIUM
is selected since that means security mode 2 which doesn't require
authentication which is something that is covered in the qualification
test L2CAP/LE/CFC/BV-25-C.
Link: https://github.com/bluez/bluez/issues/1270
Fixes: 27e2d4c8d2 ("Bluetooth: Add basic LE L2CAP connect request receiving support")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
l2cap_check_enc_key_size shall check the security level of the
l2cap_chan rather than the hci_conn since for incoming connection
request that may be different as hci_conn may already been
encrypted using a different security level.
Fixes: 522e9ed157 ("Bluetooth: l2cap: Check encryption key size on incoming connection")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Copy timestamp too when allocating new skb for received fragment.
Fixes missing RX timestamps with fragmentation.
Fixes: 4d7ea8ee90 ("Bluetooth: L2CAP: Fix handling fragmented length")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This is required for passing PTS test cases:
- L2CAP/COS/CED/BI-14-C
Multiple Signaling Command in one PDU, Data Truncated, BR/EDR,
Connection Request
- L2CAP/COS/CED/BI-15-C
Multiple Signaling Command in one PDU, Data Truncated, BR/EDR,
Disconnection Request
The test procedure defined in L2CAP.TS.p39 for both tests is:
1. The Lower Tester sends a C-frame to the IUT with PDU Length set
to 8 and Channel ID set to the correct signaling channel for the
logical link. The Information payload contains one L2CAP_ECHO_REQ
packet with Data Length set to 0 with 0 octets of echo data and
one command packet and Data Length set as specified in Table 4.6
and the correct command data.
2. The IUT sends an L2CAP_ECHO_RSP PDU to the Lower Tester.
3. Perform alternative 3A, 3B, 3C, or 3D depending on the IUT’s
response.
Alternative 3A (IUT terminates the link):
3A.1 The IUT terminates the link.
3A.2 The test ends with a Pass verdict.
Alternative 3B (IUT discards the frame):
3B.1 The IUT does not send a reply to the Lower Tester.
Alternative 3C (IUT rejects PDU):
3C.1 The IUT sends an L2CAP_COMMAND_REJECT_RSP PDU to the
Lower Tester.
Alternative 3D (Any other IUT response):
3D.1 The Upper Tester issues a warning and the test ends.
4. The Lower Tester sends a C-frame to the IUT with PDU Length set
to 4 and Channel ID set to the correct signaling channel for the
logical link. The Information payload contains Data Length set to
0 with an L2CAP_ECHO_REQ packet with 0 octets of echo data.
5. The IUT sends an L2CAP_ECHO_RSP PDU to the Lower Tester.
With expected outcome:
In Steps 2 and 5, the IUT responds with an L2CAP_ECHO_RSP.
In Step 3A.1, the IUT terminates the link.
In Step 3B.1, the IUT does not send a reply to the Lower Tester.
In Step 3C.1, the IUT rejects the PDU.
In Step 3D.1, the IUT sends any valid response.
Currently PTS fails with the following logs:
Failed to receive ECHO RESPONSE.
And HCI logs:
> ACL Data RX: Handle 11 flags 0x02 dlen 20
L2CAP: Information Response (0x0b) ident 2 len 12
Type: Fixed channels supported (0x0003)
Result: Success (0x0000)
Channels: 0x000000000000002e
L2CAP Signaling (BR/EDR)
Connectionless reception
AMP Manager Protocol
L2CAP Signaling (LE)
> ACL Data RX: Handle 11 flags 0x02 dlen 13
frame too long
08 01 00 00 08 02 01 00 aa .........
Cc: stable@vger.kernel.org
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
