Commit Graph

5248 Commits

Author SHA1 Message Date
Bastien Nocera 7835fcfd13 Bluetooth: Fix TOCTOU in HCI debugfs implementation
struct hci_dev members conn_info_max_age, conn_info_min_age,
le_conn_max_interval, le_conn_min_interval, le_adv_max_interval,
and le_adv_min_interval can be modified from the HCI core code, as well
through debugfs.

The debugfs implementation, that's only available to privileged users,
will check for boundaries, making sure that the minimum value being set
is strictly above the maximum value that already exists, and vice-versa.

However, as both minimum and maximum values can be changed concurrently
to us modifying them, we need to make sure that the value we check is
the value we end up using.

For example, with ->conn_info_max_age set to 10, conn_info_min_age_set()
gets called from vfs handlers to set conn_info_min_age to 8.

In conn_info_min_age_set(), this goes through:
	if (val == 0 || val > hdev->conn_info_max_age)
		return -EINVAL;

Concurrently, conn_info_max_age_set() gets called to set to set the
conn_info_max_age to 7:
	if (val == 0 || val > hdev->conn_info_max_age)
		return -EINVAL;
That check will also pass because we used the old value (10) for
conn_info_max_age.

After those checks that both passed, the struct hci_dev access
is mutex-locked, disabling concurrent access, but that does not matter
because the invalid value checks both passed, and we'll end up with
conn_info_min_age = 8 and conn_info_max_age = 7

To fix this problem, we need to lock the structure access before so the
check and assignment are not interrupted.

This fix was originally devised by the BassCheck[1] team, and
considered the problem to be an atomicity one. This isn't the case as
there aren't any concerns about the variable changing while we check it,
but rather after we check it parallel to another change.

This patch fixes CVE-2024-24858 and CVE-2024-24857.

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

Co-developed-by: Gui-Dong Han <2045gemini@gmail.com>
Signed-off-by: Gui-Dong Han <2045gemini@gmail.com>
Link: https://lore.kernel.org/linux-bluetooth/20231222161317.6255-1-2045gemini@gmail.com/
Link: https://nvd.nist.gov/vuln/detail/CVE-2024-24858
Link: https://lore.kernel.org/linux-bluetooth/20231222162931.6553-1-2045gemini@gmail.com/
Link: https://lore.kernel.org/linux-bluetooth/20231222162310.6461-1-2045gemini@gmail.com/
Link: https://nvd.nist.gov/vuln/detail/CVE-2024-24857
Fixes: 31ad169148 ("Bluetooth: Add conn info lifetime parameters to debugfs")
Fixes: 729a1051da ("Bluetooth: Expose default LE advertising interval via debugfs")
Fixes: 71c3b60ec6 ("Bluetooth: Move BR/EDR debugfs file creation into hci_debugfs.c")
Signed-off-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-29 09:48:37 -04:00
Hui Wang c569242cd4 Bluetooth: hci_event: set the conn encrypted before conn establishes
We have a BT headset (Lenovo Thinkplus XT99), the pairing and
connecting has no problem, once this headset is paired, bluez will
remember this device and will auto re-connect it whenever the device
is powered on. The auto re-connecting works well with Windows and
Android, but with Linux, it always fails. Through debugging, we found
at the rfcomm connection stage, the bluetooth stack reports
"Connection refused - security block (0x0003)".

For this device, the re-connecting negotiation process is different
from other BT headsets, it sends the Link_KEY_REQUEST command before
the CONNECT_REQUEST completes, and it doesn't send ENCRYPT_CHANGE
command during the negotiation. When the device sends the "connect
complete" to hci, the ev->encr_mode is 1.

So here in the conn_complete_evt(), if ev->encr_mode is 1, link type
is ACL and HCI_CONN_ENCRYPT is not set, we set HCI_CONN_ENCRYPT to
this conn, and update conn->enc_key_size accordingly.

After this change, this BT headset could re-connect with Linux
successfully. This is the btmon log after applying the patch, after
receiving the "Connect Complete" with "Encryption: Enabled", will send
the command to read encryption key size:
> HCI Event: Connect Request (0x04) plen 10
        Address: 8C:3C:AA:D8:11:67 (OUI 8C-3C-AA)
        Class: 0x240404
          Major class: Audio/Video (headset, speaker, stereo, video, vcr)
          Minor class: Wearable Headset Device
          Rendering (Printing, Speaker)
          Audio (Speaker, Microphone, Headset)
        Link type: ACL (0x01)
...
> HCI Event: Link Key Request (0x17) plen 6
        Address: 8C:3C:AA:D8:11:67 (OUI 8C-3C-AA)
< HCI Command: Link Key Request Reply (0x01|0x000b) plen 22
        Address: 8C:3C:AA:D8:11:67 (OUI 8C-3C-AA)
        Link key: ${32-hex-digits-key}
...
> HCI Event: Connect Complete (0x03) plen 11
        Status: Success (0x00)
        Handle: 256
        Address: 8C:3C:AA:D8:11:67 (OUI 8C-3C-AA)
        Link type: ACL (0x01)
        Encryption: Enabled (0x01)
< HCI Command: Read Encryption Key... (0x05|0x0008) plen 2
        Handle: 256
< ACL Data TX: Handle 256 flags 0x00 dlen 10
      L2CAP: Information Request (0x0a) ident 1 len 2
        Type: Extended features supported (0x0002)
> HCI Event: Command Complete (0x0e) plen 7
      Read Encryption Key Size (0x05|0x0008) ncmd 1
        Status: Success (0x00)
        Handle: 256
        Key size: 16

Cc: stable@vger.kernel.org
Link: https://github.com/bluez/bluez/issues/704
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-29 09:48:37 -04:00
Luiz Augusto von Dentz 6946b9c99b Bluetooth: hci_sync: Fix not checking error on hci_cmd_sync_cancel_sync
hci_cmd_sync_cancel_sync shall check the error passed to it since it
will be propagated using req_result which is __u32 it needs to be
properly set to a positive value if it was passed as negative othertise
IS_ERR will not trigger as -(errno) would be converted to a positive
value.

Fixes: 63298d6e75 ("Bluetooth: hci_core: Cancel request on command timeout")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reported-and-tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Closes: https://lore.kernel.org/all/08275279-7462-4f4a-a0ee-8aa015f829bc@leemhuis.info/
2024-03-29 09:48:37 -04:00
Johan Hovold 39646f29b1 Bluetooth: add quirk for broken address properties
Some Bluetooth controllers lack persistent storage for the device
address and instead one can be provided by the boot firmware using the
'local-bd-address' devicetree property.

The Bluetooth devicetree bindings clearly states that the address should
be specified in little-endian order, but due to a long-standing bug in
the Qualcomm driver which reversed the address some boot firmware has
been providing the address in big-endian order instead.

Add a new quirk that can be set on platforms with broken firmware and
use it to reverse the address when parsing the property so that the
underlying driver bug can be fixed.

Fixes: 5c0a1001c8 ("Bluetooth: hci_qca: Add helper to set device address")
Cc: stable@vger.kernel.org      # 5.1
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-29 09:48:37 -04:00
Luiz Augusto von Dentz 3d1c16e920 Bluetooth: hci_sync: Fix UAF in hci_acl_create_conn_sync
This fixes the following error caused by hci_conn being freed while
hcy_acl_create_conn_sync is pending:

==================================================================
BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0xa7/0x2e0
Write of size 2 at addr ffff888002ae0036 by task kworker/u3:0/848

CPU: 0 PID: 848 Comm: kworker/u3:0 Not tainted 6.8.0-rc6-g2ab3e8d67fc1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38
04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x21/0x70
 print_report+0xce/0x620
 ? preempt_count_sub+0x13/0xc0
 ? __virt_addr_valid+0x15f/0x310
 ? hci_acl_create_conn_sync+0xa7/0x2e0
 kasan_report+0xdf/0x110
 ? hci_acl_create_conn_sync+0xa7/0x2e0
 hci_acl_create_conn_sync+0xa7/0x2e0
 ? __pfx_hci_acl_create_conn_sync+0x10/0x10
 ? __pfx_lock_release+0x10/0x10
 ? __pfx_hci_acl_create_conn_sync+0x10/0x10
 hci_cmd_sync_work+0x138/0x1c0
 process_one_work+0x405/0x800
 ? __pfx_lock_acquire+0x10/0x10
 ? __pfx_process_one_work+0x10/0x10
 worker_thread+0x37b/0x670
 ? __pfx_worker_thread+0x10/0x10
 kthread+0x19b/0x1e0
 ? kthread+0xfe/0x1e0
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x2f/0x50
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 847:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 __kasan_kmalloc+0x8f/0xa0
 hci_conn_add+0xc6/0x970
 hci_connect_acl+0x309/0x410
 pair_device+0x4fb/0x710
 hci_sock_sendmsg+0x933/0xef0
 sock_write_iter+0x2c3/0x2d0
 do_iter_readv_writev+0x21a/0x2e0
 vfs_writev+0x21c/0x7b0
 do_writev+0x14a/0x180
 do_syscall_64+0x77/0x150
 entry_SYSCALL_64_after_hwframe+0x6c/0x74

Freed by task 847:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3b/0x60
 __kasan_slab_free+0xfa/0x150
 kfree+0xcb/0x250
 device_release+0x58/0xf0
 kobject_put+0xbb/0x160
 hci_conn_del+0x281/0x570
 hci_conn_hash_flush+0xfc/0x130
 hci_dev_close_sync+0x336/0x960
 hci_dev_close+0x10e/0x140
 hci_sock_ioctl+0x14a/0x5c0
 sock_ioctl+0x58a/0x5d0
 __x64_sys_ioctl+0x480/0xf60
 do_syscall_64+0x77/0x150
 entry_SYSCALL_64_after_hwframe+0x6c/0x74

Fixes: 45340097ce ("Bluetooth: hci_conn: Only do ACL connections sequentially")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-08 11:06:14 -05:00
Frédéric Danis 2ab3e8d67f Bluetooth: Fix eir name length
According to Section 1.2 of Core Specification Supplement Part A the
complete or short name strings are defined as utf8s, which should not
include the trailing NULL for variable length array as defined in Core
Specification Vol1 Part E Section 2.9.3.

Removing the trailing NULL allows PTS to retrieve the random address based
on device name, e.g. for SM/PER/KDU/BV-02-C, SM/PER/KDU/BV-08-C or
GAP/BROB/BCST/BV-03-C.

Fixes: f61851f64b ("Bluetooth: Fix append max 11 bytes of name to scan rsp data")
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-08 10:22:17 -05:00
Luiz Augusto von Dentz 42ed95de82 Bluetooth: ISO: Align broadcast sync_timeout with connection timeout
This aligns broadcast sync_timeout with existing connection timeouts
which are 20 seconds long.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-07 11:58:17 -05:00
Vinicius Peixoto 48201a3b3f Bluetooth: Add new quirk for broken read key length on ATS2851
The ATS2851 controller erroneously reports support for the "Read
Encryption Key Length" HCI command. This makes it unable to connect
to any devices, since this command is issued by the kernel during the
connection process in response to an "Encryption Change" HCI event.

Add a new quirk (HCI_QUIRK_BROKEN_ENC_KEY_SIZE) to hint that the command
is unsupported, preventing it from interrupting the connection process.

This is the error log from btmon before this patch:

> HCI Event: Encryption Change (0x08) plen 4
        Status: Success (0x00)
        Handle: 2048 Address: ...
        Encryption: Enabled with E0 (0x01)
< HCI Command: Read Encryption Key Size (0x05|0x0008) plen 2
        Handle: 2048 Address: ...
> HCI Event: Command Status (0x0f) plen 4
      Read Encryption Key Size (0x05|0x0008) ncmd 1
        Status: Unknown HCI Command (0x01)

Signed-off-by: Vinicius Peixoto <nukelet64@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:27:14 -05:00
Roman Smirnov a310d74dce Bluetooth: mgmt: remove NULL check in add_ext_adv_params_complete()
Remove the cmd pointer NULL check in add_ext_adv_params_complete()
because it occurs earlier in add_ext_adv_params(). This check is
also unnecessary because the pointer is dereferenced just before it.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:27:13 -05:00
Roman Smirnov 3237da12a3 Bluetooth: mgmt: remove NULL check in mgmt_set_connectable_complete()
Remove the cmd pointer NULL check in mgmt_set_connectable_complete()
because it occurs earlier in set_connectable(). This check is also
unnecessary because the pointer is dereferenced just before it.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:27:12 -05:00
Dan Carpenter 18d88f0fd8 Bluetooth: ISO: Clean up returns values in iso_connect_ind()
This function either returns 0 or HCI_LM_ACCEPT.  Make it clearer which
returns are which and delete the "lm" variable because it is no longer
required.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:27:09 -05:00
Pauli Virtanen 947ec0d002 Bluetooth: fix use-after-free in accessing skb after sending it
hci_send_cmd_sync first sends skb and then tries to clone it.  However,
the driver may have already freed the skb at that point.

Fix by cloning the sent_cmd cloned just above, instead of the original.

Log:
================================================================
BUG: KASAN: slab-use-after-free in __copy_skb_header+0x1a/0x240
...
Call Trace: ..
 __skb_clone+0x59/0x2c0
 hci_cmd_work+0x3b3/0x3d0 [bluetooth]
 process_one_work+0x459/0x900
...
Allocated by task 129: ...
 __alloc_skb+0x1ae/0x220
 __hci_cmd_sync_sk+0x44c/0x7a0 [bluetooth]
 __hci_cmd_sync_status+0x24/0xb0 [bluetooth]
 set_cig_params_sync+0x778/0x7d0 [bluetooth]
...
Freed by task 0: ...
 kmem_cache_free+0x157/0x3c0
 __usb_hcd_giveback_urb+0x11e/0x1e0
 usb_giveback_urb_bh+0x1ad/0x2a0
 tasklet_action_common.isra.0+0x259/0x4a0
 __do_softirq+0x15b/0x5a7
================================================================

Fixes: 2615fd9a7c ("Bluetooth: hci_sync: Fix overwriting request callback")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:58 -05:00
Luiz Augusto von Dentz f7b94bdc1e Bluetooth: af_bluetooth: Fix deadlock
Attemting to do sock_lock on .recvmsg may cause a deadlock as shown
bellow, so instead of using sock_sock this uses sk_receive_queue.lock
on bt_sock_ioctl to avoid the UAF:

INFO: task kworker/u9:1:121 blocked for more than 30 seconds.
      Not tainted 6.7.6-lemon #183
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __schedule+0x37d/0xa00
 schedule+0x32/0xe0
 __lock_sock+0x68/0xa0
 ? __pfx_autoremove_wake_function+0x10/0x10
 lock_sock_nested+0x43/0x50
 l2cap_sock_recv_cb+0x21/0xa0
 l2cap_recv_frame+0x55b/0x30a0
 ? psi_task_switch+0xeb/0x270
 ? finish_task_switch.isra.0+0x93/0x2a0
 hci_rx_work+0x33a/0x3f0
 process_one_work+0x13a/0x2f0
 worker_thread+0x2f0/0x410
 ? __pfx_worker_thread+0x10/0x10
 kthread+0xe0/0x110
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x2c/0x50
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1b/0x30
 </TASK>

Fixes: 2e07e8348e ("Bluetooth: af_bluetooth: Fix Use-After-Free in bt_sock_recvmsg")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:25 -05:00
Luiz Augusto von Dentz 0f0639b4d6 Bluetooth: bnep: Fix out-of-bound access
This fixes attempting to access past ethhdr.h_source, although it seems
intentional to copy also the contents of h_proto this triggers
out-of-bound access problems with the likes of static analyzer, so this
instead just copy ETH_ALEN and then proceed to use put_unaligned to copy
h_proto separetely.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:24 -05:00
Luiz Augusto von Dentz a6e06258f4 Bluetooth: msft: Fix memory leak
Fix leaking buffer allocated to send MSFT_OP_LE_MONITOR_ADVERTISEMENT.

Fixes: 9e14606d8f ("Bluetooth: msft: Extended monitor tracking by address filter")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:23 -05:00
Luiz Augusto von Dentz 81137162bf Bluetooth: hci_core: Fix possible buffer overflow
struct hci_dev_info has a fixed size name[8] field so in the event that
hdev->name is bigger than that strcpy would attempt to write past its
size, so this fixes this problem by switching to use strscpy.

Fixes: dcda165706 ("Bluetooth: hci_core: Fix build warnings")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:22 -05:00
Luiz Augusto von Dentz 2615fd9a7c Bluetooth: hci_sync: Fix overwriting request callback
In a few cases the stack may generate commands as responses to events
which would happen to overwrite the sent_cmd, so this attempts to store
the request in req_skb so even if sent_cmd is replaced with a new
command the pending request will remain in stored in req_skb.

Fixes: 6a98e3836f ("Bluetooth: Add helper for serialized HCI command execution")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:20 -05:00
Luiz Augusto von Dentz 22cbf4f84c Bluetooth: hci_sync: Use QoS to determine which PHY to scan
This used the hci_conn QoS to determine which PHY to scan when creating
a PA Sync.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:20 -05:00
Luiz Augusto von Dentz bba71ef13b Bluetooth: hci_sync: Use address filtering when HCI_PA_SYNC is set
If HCI_PA_SYNC flag is set it means there is a Periodic Advertising
Synchronization pending, so this attempts to locate the address passed
to HCI_OP_LE_PA_CREATE_SYNC and program it in the accept list so only
reports with that address are processed.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:19 -05:00
Iulia Tanasescu 168d9bf9c7 Bluetooth: ISO: Reassemble PA data for bcast sink
This adds support to reassemble PA data for a Broadcast Sink
listening socket. This is needed in case the BASE is received
fragmented in multiple PA reports.

PA data is first reassembled inside the hcon, before the BASE
is extracted and stored inside the socket. The length of the
le_per_adv_data hcon array has been raised to 1650, to accommodate
the maximum PA data length that can come fragmented, according to
spec.

Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:19 -05:00
Iulia Tanasescu 02171da6e8 Bluetooth: ISO: Add hcon for listening bis sk
This creates a hcon instance at bis listen, before the PA sync
procedure is started.

Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:26:18 -05:00
Luiz Augusto von Dentz f7cbce60a3 Bluetooth: hci_sync: Fix UAF on create_le_conn_complete
While waiting for hci_dev_lock the hci_conn object may be cleanup
causing the following trace:

BUG: KASAN: slab-use-after-free in hci_connect_le_scan_cleanup+0x29/0x350
Read of size 8 at addr ffff888001a50a30 by task kworker/u3:1/111

CPU: 0 PID: 111 Comm: kworker/u3:1 Not tainted
6.8.0-rc2-00701-g8179b15ab3fd-dirty #6418
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38
04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x21/0x70
 print_report+0xce/0x620
 ? preempt_count_sub+0x13/0xc0
 ? __virt_addr_valid+0x15f/0x310
 ? hci_connect_le_scan_cleanup+0x29/0x350
 kasan_report+0xdf/0x110
 ? hci_connect_le_scan_cleanup+0x29/0x350
 hci_connect_le_scan_cleanup+0x29/0x350
 create_le_conn_complete+0x25c/0x2c0

Fixes: 881559af5f ("Bluetooth: hci_sync: Attempt to dequeue connection attempt")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:25:21 -05:00
Luiz Augusto von Dentz 7453847fb2 Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync
Fixes the following trace where hci_acl_create_conn_sync attempts to
call hci_abort_conn_sync after timeout:

BUG: KASAN: slab-use-after-free in hci_abort_conn_sync
(net/bluetooth/hci_sync.c:5439)
Read of size 2 at addr ffff88800322c032 by task kworker/u3:2/36

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38
04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
<TASK>
dump_stack_lvl (./arch/x86/include/asm/irqflags.h:26
./arch/x86/include/asm/irqflags.h:67 ./arch/x86/include/asm/irqflags.h:127
lib/dump_stack.c:107)
print_report (mm/kasan/report.c:378 mm/kasan/report.c:488)
? preempt_count_sub (kernel/sched/core.c:5889)
? __virt_addr_valid (./arch/x86/include/asm/preempt.h:103 (discriminator 1)
./include/linux/rcupdate.h:865 (discriminator 1)
./include/linux/mmzone.h:2026 (discriminator 1)
arch/x86/mm/physaddr.c:65 (discriminator 1))
? hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
kasan_report (mm/kasan/report.c:603)
? hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
hci_abort_conn_sync (net/bluetooth/hci_sync.c:5439)
? __pfx_hci_abort_conn_sync (net/bluetooth/hci_sync.c:5433)
hci_acl_create_conn_sync (net/bluetooth/hci_sync.c:6681)

Fixes: 45340097ce ("Bluetooth: hci_conn: Only do ACL connections sequentially")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:24:28 -05:00
Ricardo B. Marliere 412b894a18 Bluetooth: constify the struct device_type usage
Since commit aed65af1cc ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the bt_type and
bnep_type variables to be constant structures as well, placing it into
read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:24:07 -05:00
Luiz Augusto von Dentz 881559af5f Bluetooth: hci_sync: Attempt to dequeue connection attempt
If connection is still queued/pending in the cmd_sync queue it means no
command has been generated and it should be safe to just dequeue the
callback when it is being aborted.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:24:06 -05:00
Luiz Augusto von Dentz 505ea2b295 Bluetooth: hci_sync: Add helper functions to manipulate cmd_sync queue
This adds functions to queue, dequeue and lookup into the cmd_sync
list.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:24:05 -05:00
Luiz Augusto von Dentz 5f641f03ab Bluetooth: hci_conn: Fix UAF Write in __hci_acl_create_connection_sync
This fixes the UAF on __hci_acl_create_connection_sync caused by
connection abortion, it uses the same logic as to LE_LINK which uses
hci_cmd_sync_cancel to prevent the callback to run if the connection is
abort prematurely.

Reported-by: syzbot+3f0a39be7a2035700868@syzkaller.appspotmail.com
Fixes: 45340097ce ("Bluetooth: hci_conn: Only do ACL connections sequentially")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:23:52 -05:00
Luiz Augusto von Dentz bf98feea5b Bluetooth: hci_conn: Always use sk_timeo as conn_timeout
This aligns the use socket sk_timeo as conn_timeout when initiating a
connection and then use it when scheduling the resulting HCI command,
that way the command is actually aborted synchronously thus not
blocking commands generated by hci_abort_conn_sync to inform the
controller the connection is to be aborted.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:41 -05:00
Lukas Bulwahn f4b0c2b4cd Bluetooth: hci_event: Remove code to removed CONFIG_BT_HS
Commit cec9f3c5561d ("Bluetooth: Remove BT_HS") removes config BT_HS, but
misses two "ifdef BT_HS" blocks in hci_event.c.

Remove this dead code from this removed config option.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:41 -05:00
Jonas Dreßler 4aa42119d9 Bluetooth: Remove pending ACL connection attempts
With the last commit we moved to using the hci_sync queue for "Create
Connection" requests, removing the need for retrying the paging after
finished/failed "Create Connection" requests and after the end of
inquiries.

hci_conn_check_pending() was used to trigger this retry, we can remove it
now.

Note that we can also remove the special handling for COMMAND_DISALLOWED
errors in the completion handler of "Create Connection", because "Create
Connection" requests are now always serialized.

This is somewhat reverting commit 4c67bc74f0 ("[Bluetooth] Support
concurrent connect requests").

With this, the BT_CONNECT2 state of ACL hci_conn objects should now be
back to meaning only one thing: That we received a "Connection Request"
from another device (see hci_conn_request_evt), but the response to that
is going to be deferred.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:40 -05:00
Jonas Dreßler 45340097ce Bluetooth: hci_conn: Only do ACL connections sequentially
Pretty much all bluetooth chipsets only support paging a single device at
a time, and if they don't reject a secondary "Create Connection" request
while another is still ongoing, they'll most likely serialize those
requests in the firware.

With commit 4c67bc74f0 ("[Bluetooth] Support concurrent connect
requests") we started adding some serialization of our own in case the
adapter returns "Command Disallowed" HCI error.

This commit was using the BT_CONNECT2 state for the serialization, this
state is also used for a few more things (most notably to indicate we're
waiting for an inquiry to cancel) and therefore a bit unreliable. Also
not all BT firwares would respond with "Command Disallowed" on too many
connection requests, some will also respond with "Hardware Failure"
(BCM4378), and others will error out later and send a "Connect Complete"
event with error "Rejected Limited Resources" (Marvell 88W8897).

We can clean things up a bit and also make the serialization more reliable
by using our hci_sync machinery to always do "Create Connection" requests
in a sequential manner.

This is very similar to what we're already doing for establishing LE
connections, and it works well there.

Note that this causes a test failure in mgmt-tester (test "Pair Device
- Power off 1") because the hci_abort_conn_sync() changes the error we
return on timeout of the "Create Connection". We'll fix this on the
mgmt-tester side by adjusting the expected error for the test.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:40 -05:00
Luiz Augusto von Dentz eeda1bf97b Bluetooth: hci_event: Fix not indicating new connection for BIG Sync
BIG Sync (aka. Broadcast sink) requires to inform that the device is
connected when a data path is active otherwise userspace could attempt
to free resources allocated to the device object while scanning.

Fixes: 1d11d70d1f ("Bluetooth: ISO: Pass BIG encryption info through QoS")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:39 -05:00
Luiz Augusto von Dentz e7b02296fb Bluetooth: Remove BT_HS
High Speed, Alternate MAC and PHY (AMP) extension, has been removed from
Bluetooth Core specification on 5.3:

https://www.bluetooth.com/blog/new-core-specification-v5-3-feature-enhancements/

Fixes: 244bc37759 ("Bluetooth: Add BT_HS config option")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:39 -05:00
Christophe JAILLET 9c16d0c8d9 Bluetooth: Remove usage of the deprecated ida_simple_xx() API
ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. So a -1 has been added when needed.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:38 -05:00
Luiz Augusto von Dentz 63298d6e75 Bluetooth: hci_core: Cancel request on command timeout
If command has timed out call __hci_cmd_sync_cancel to notify the
hci_req since it will inevitably cause a timeout.

This also rework the code around __hci_cmd_sync_cancel since it was
wrongly assuming it needs to cancel timer as well, but sometimes the
timers have not been started or in fact they already had timed out in
which case they don't need to be cancel yet again.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:38 -05:00
Jonas Dreßler 79c0868ad6 Bluetooth: hci_event: Use HCI error defines instead of magic values
We have error defines already, so let's use them.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:38 -05:00
Jonas Dreßler 78e3639fc8 Bluetooth: Remove superfluous call to hci_conn_check_pending()
The "pending connections" feature was originally introduced with commit
4c67bc74f0 ("[Bluetooth] Support concurrent connect requests") and
6bd5741612 ("[Bluetooth] Handling pending connect attempts after
inquiry") to handle controllers supporting only a single connection request
at a time. Later things were extended to also cancel ongoing inquiries on
connect() with commit 89e65975fe ("Bluetooth: Cancel Inquiry before
Create Connection").

With commit a9de924806 ("[Bluetooth] Switch from OGF+OCF to using only
opcodes"), hci_conn_check_pending() was introduced as a helper to
consolidate a few places where we check for pending connections (indicated
by the BT_CONNECT2 flag) and then try to connect.

This refactoring commit also snuck in two more calls to
hci_conn_check_pending():

- One is in the failure callback of hci_cs_inquiry(), this one probably
makes sense: If we send an "HCI Inquiry" command and then immediately
after a "Create Connection" command, the "Create Connection" command might
fail before the "HCI Inquiry" command, and then we want to retry the
"Create Connection" on failure of the "HCI Inquiry".

- The other added call to hci_conn_check_pending() is in the event handler
for the "Remote Name" event, this seems unrelated and is possibly a
copy-paste error, so remove that one.

Fixes: a9de924806 ("[Bluetooth] Switch from OGF+OCF to using only opcodes")
Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:37 -05:00
Jonas Dreßler d77433cdd2 Bluetooth: Disconnect connected devices before rfkilling adapter
On a lot of platforms (at least the MS Surface devices, M1 macbooks, and
a few ThinkPads) firmware doesn't do its job when rfkilling a device
and the bluetooth adapter is not actually shut down properly on rfkill.
This leads to connected devices remaining in connected state and the
bluetooth connection eventually timing out after rfkilling an adapter.

Use the rfkill hook in the HCI driver to go through the full power-off
sequence (including stopping scans and disconnecting devices) before
rfkilling it, just like MGMT_OP_SET_POWERED would do.

In case anything during the larger power-off sequence fails, make sure
the device is still closed and the rfkill ends up being effective in
the end.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:37 -05:00
Jonas Dreßler b14202aff5 Bluetooth: Add new state HCI_POWERING_DOWN
Add a new state HCI_POWERING_DOWN that indicates that the device is
currently powering down, this will be useful for the next commit.

Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:37 -05:00
Jonas Dreßler fee054b757 Bluetooth: mgmt: Remove leftover queuing of power_off work
Queuing of power_off work was introduced in these functions with commits
8b064a3ad3 ("Bluetooth: Clean up HCI state when doing power off") and
c9910d0fb4 ("Bluetooth: Fix disconnecting connections in non-connected
states") in an effort to clean up state and do things like disconnecting
devices before actually powering off the device.

After that, commit a3172b7eb4 ("Bluetooth: Add timer to force power off")
introduced a timeout to ensure that the device actually got powered off,
even if some of the cleanup work would never complete.

This code later got refactored with commit cf75ad8b41 ("Bluetooth:
hci_sync: Convert MGMT_SET_POWERED"), which made powering off the device
synchronous and removed the need for initiating the power_off work from
other places. The timeout mentioned above got removed too, because we now
also made use of the command timeout during power on/off.

These days the power_off work still exists, but it only seems to only be
used for HCI_AUTO_OFF functionality, which is why we never noticed
those two leftover places where we queue power_off work. So let's remove
that code.

Fixes: cf75ad8b41 ("Bluetooth: hci_sync: Convert MGMT_SET_POWERED")
Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-03-06 17:22:37 -05:00
Kai-Heng Feng e4b019515f Bluetooth: Enforce validation on max value of connection interval
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 c49a8682fc ("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: 68d19d7d99 ("Revert "Bluetooth: validate BLE connection interval updates"")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:44:11 -05:00
Luiz Augusto von Dentz 7e74aa53a6 Bluetooth: hci_event: Fix handling of HCI_EV_IO_CAPA_REQUEST
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: c7f59461f5 ("Bluetooth: Fix a refcnt underflow problem for hci_conn")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:43:49 -05:00
Frédéric Danis 0bd1fb5862 Bluetooth: mgmt: Fix limited discoverable off timeout
LIMITED_DISCOVERABLE flag is not reset from Class of Device and
advertisement on limited discoverable timeout. This prevents to pass PTS
test GAP/DISC/LIMM/BV-02-C

Calling set_discoverable_sync as when the limited discovery is set
correctly update the Class of Device and advertisement.

Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:43:20 -05:00
Zijun Hu 61a5ab72ed Bluetooth: hci_event: Fix wrongly recorded wakeup BD_ADDR
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: 2f20216c1d ("Bluetooth: Emit controller suspend and resume events")
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:42:54 -05:00
Yuxuan Hu 2535b848fa Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security
During our fuzz testing of the connection and disconnection process at the
RFCOMM layer, we discovered this bug. By comparing the packets from a
normal connection and disconnection process with the testcase that
triggered a KASAN report. We analyzed the cause of this bug as follows:

1. In the packets captured during a normal connection, the host sends a
`Read Encryption Key Size` type of `HCI_CMD` packet
(Command Opcode: 0x1408) to the controller to inquire the length of
encryption key.After receiving this packet, the controller immediately
replies with a Command Completepacket (Event Code: 0x0e) to return the
Encryption Key Size.

2. In our fuzz test case, the timing of the controller's response to this
packet was delayed to an unexpected point: after the RFCOMM and L2CAP
layers had disconnected but before the HCI layer had disconnected.

3. After receiving the Encryption Key Size Response at the time described
in point 2, the host still called the rfcomm_check_security function.
However, by this time `struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;`
had already been released, and when the function executed
`return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);`,
specifically when accessing `conn->hcon`, a null-ptr-deref error occurred.

To fix this bug, check if `sk->sk_state` is BT_CLOSED before calling
rfcomm_recv_frame in rfcomm_process_rx.

Signed-off-by: Yuxuan Hu <20373622@buaa.edu.cn>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:42:26 -05:00
Luiz Augusto von Dentz e5469adb2a Bluetooth: hci_sync: Fix accept_list when attempting to suspend
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: 3b42055388 ("Bluetooth: hci_sync: Fix attempting to suspend with unfiltered passive scan")
Signed-off-by: Clancy Shang <clancy.shang@quectel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
2024-02-28 09:42:02 -05:00
Ying Hsu 2449007d3f Bluetooth: Avoid potential use-after-free in hci_error_reset
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 <HASH:3b4a6>]
   ? init_wait_entry+0x31/0x31
   __hci_cmd_sync+0x16/0x20 [bluetooth <HASH:3b4a 6>]
   hci_error_reset+0x4f/0xa4 [bluetooth <HASH:3b4a 6>]
   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: c7741d16a5 ("Bluetooth: Perform a power cycle when receiving hardware error event")
Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:41:35 -05:00
Jonas Dreßler 6b3899be24 Bluetooth: hci_sync: Check the correct flag before starting a scan
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->dev_flags instead of hdev->flags. HCI_INQUIRY is a bit that's
set on hdev->flags, not on hdev->dev_flags though.

HCI_INQUIRY equals the integer 7, and in hdev->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: abfeea476c ("Bluetooth: hci_sync: Convert MGMT_OP_START_DISCOVERY")
Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2024-02-28 09:41:10 -05:00
Linus Torvalds bd736f38c0 TTY/Serial changes for 6.8-rc1
Here is the big set of tty and serial driver changes for 6.8-rc1.
 
 As usual, Jiri has a bunch of refactoring and cleanups for the tty core
 and drivers in here, along with the usual set of rs485 updates (someday
 this might work properly...)  Along with those, in here are changes for:
   - sc16is7xx serial driver updates
   - platform driver removal api updates
   - amba-pl011 driver updates
   - tty driver binding updates
   - other small tty/serial driver updates and changes
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial updates from Greg KH:
 "Here is the big set of tty and serial driver changes for 6.8-rc1.

  As usual, Jiri has a bunch of refactoring and cleanups for the tty
  core and drivers in here, along with the usual set of rs485 updates
  (someday this might work properly...)

  Along with those, in here are changes for:

   - sc16is7xx serial driver updates

   - platform driver removal api updates

   - amba-pl011 driver updates

   - tty driver binding updates

   - other small tty/serial driver updates and changes

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (197 commits)
  serial: sc16is7xx: refactor EFR lock
  serial: sc16is7xx: reorder code to remove prototype declarations
  serial: sc16is7xx: refactor FIFO access functions to increase commonality
  serial: sc16is7xx: drop unneeded MODULE_ALIAS
  serial: sc16is7xx: replace hardcoded divisor value with BIT() macro
  serial: sc16is7xx: add explicit return for some switch default cases
  serial: sc16is7xx: add macro for max number of UART ports
  serial: sc16is7xx: add driver name to struct uart_driver
  serial: sc16is7xx: use i2c_get_match_data()
  serial: sc16is7xx: use spi_get_device_match_data()
  serial: sc16is7xx: use DECLARE_BITMAP for sc16is7xx_lines bitfield
  serial: sc16is7xx: improve do/while loop in sc16is7xx_irq()
  serial: sc16is7xx: remove obsolete loop in sc16is7xx_port_irq()
  serial: sc16is7xx: set safe default SPI clock frequency
  serial: sc16is7xx: add check for unsupported SPI modes during probe
  serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error
  serial: 8250_exar: Set missing rs485_supported flag
  serial: omap: do not override settings for RS485 support
  serial: core, imx: do not set RS485 enabled if it is not supported
  serial: core: make sure RS485 cannot be enabled when it is not supported
  ...
2024-01-18 11:37:24 -08:00
Gui-Dong Han da9065caa5 Bluetooth: Fix atomicity violation in {min,max}_key_size_set
In min_key_size_set():
    if (val > hdev->le_max_key_size || val < SMP_MIN_ENC_KEY_SIZE)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev->le_min_key_size = val;
    hci_dev_unlock(hdev);

In max_key_size_set():
    if (val > SMP_MAX_ENC_KEY_SIZE || val < hdev->le_min_key_size)
        return -EINVAL;
    hci_dev_lock(hdev);
    hdev->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: 18f81241b7 ("Bluetooth: Move {min,max}_key_size debugfs ...")
Cc: stable@vger.kernel.org
Signed-off-by: Gui-Dong Han <2045gemini@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2023-12-22 13:00:36 -05:00