linux.git/net/bluetooth, branch v6.6

Bluetooth: hci_sock: Correctly bounds check and pad HCI_MON_NEW_INDEX name

2023-10-14T03:06:33+00:00

The code pattern of memcpy(dst, src, strlen(src)) is almost always
wrong. In this case it is wrong because it leaves memory uninitialized
if it is less than sizeof(ni->name), and overflows ni->name when longer.

Normally strtomem_pad() could be used here, but since ni->name is a
trailing array in struct hci_mon_new_index, compilers that don't support
-fstrict-flex-arrays=3 can't tell how large this array is via
__builtin_object_size(). Instead, open-code the helper and use sizeof()
since it will work correctly.

Additionally mark ni->name as __nonstring since it appears to not be a
%NUL terminated C string.

Cc: Luiz Augusto von Dentz 
Cc: Edward AD 
Cc: Marcel Holtmann 
Cc: Johan Hedberg 
Cc: "David S. Miller" 
Cc: Eric Dumazet 
Cc: Jakub Kicinski 
Cc: Paolo Abeni 
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Fixes: 18f547f3fc07 ("Bluetooth: hci_sock: fix slab oob read in create_monitor_event")
Link: https://lore.kernel.org/lkml/202310110908.F2639D3276@keescook/
Signed-off-by: Kees Cook 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: avoid memcmp() out of bounds warning

2023-10-14T03:04:45+00:00

bacmp() is a wrapper around memcpy(), which contain compile-time
checks for buffer overflow. Since the hci_conn_request_evt() also calls
bt_dev_dbg() with an implicit NULL pointer check, the compiler is now
aware of a case where 'hdev' is NULL and treats this as meaning that
zero bytes are available:

In file included from net/bluetooth/hci_event.c:32:
In function 'bacmp',
    inlined from 'hci_conn_request_evt' at net/bluetooth/hci_event.c:3276:7:
include/net/bluetooth/bluetooth.h:364:16: error: 'memcmp' specified bound 6 exceeds source size 0 [-Werror=stringop-overread]
  364 |         return memcmp(ba1, ba2, sizeof(bdaddr_t));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Add another NULL pointer check before the bacmp() to ensure the compiler
understands the code flow enough to not warn about it.  Since the patch
that introduced the warning is marked for stable backports, this one
should also go that way to avoid introducing build regressions.

Fixes: 1ffc6f8cc332 ("Bluetooth: Reject connection with the device which has same BD_ADDR")
Cc: Kees Cook 
Cc: "Lee, Chun-Yi" 
Cc: Luiz Augusto von Dentz 
Cc: Marcel Holtmann 
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann 
Reviewed-by: Kees Cook 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: hci_sock: fix slab oob read in create_monitor_event

2023-10-14T03:03:04+00:00

When accessing hdev->name, the actual string length should prevail

Reported-by: syzbot+c90849c50ed209d77689@syzkaller.appspotmail.com
Fixes: dcda165706b9 ("Bluetooth: hci_core: Fix build warnings")
Signed-off-by: Edward AD 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: hci_event: Fix coding style

2023-10-14T03:02:35+00:00

This fixes the following code style problem:

ERROR: that open brace { should be on the previous line
+	if (!bacmp(&hdev->bdaddr, &ev->bdaddr))
+	{

Fixes: 1ffc6f8cc332 ("Bluetooth: Reject connection with the device which has same BD_ADDR")
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: hci_event: Fix using memcmp when comparing keys

2023-10-14T03:00:25+00:00

memcmp is not consider safe to use with cryptographic secrets:

 'Do  not  use memcmp() to compare security critical data, such as
 cryptographic secrets, because the required CPU time depends on the
 number of equal bytes.'

While usage of memcmp for ZERO_KEY may not be considered a security
critical data, it can lead to more usage of memcmp with pairing keys
which could introduce more security problems.

Fixes: 455c2ff0a558 ("Bluetooth: Fix BR/EDR out-of-band pairing with only initiator data")
Fixes: 33155c4aae52 ("Bluetooth: hci_event: Ignore NULL link key")
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: Fix a refcnt underflow problem for hci_conn

2023-10-11T18:17:08+00:00

Syzbot reports a warning as follows:

WARNING: CPU: 1 PID: 26946 at net/bluetooth/hci_conn.c:619
hci_conn_timeout+0x122/0x210 net/bluetooth/hci_conn.c:619
...
Call Trace:
 
 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
 kthread+0x33c/0x440 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 

It is because the HCI_EV_SIMPLE_PAIR_COMPLETE event handler drops
hci_conn directly without check Simple Pairing whether be enabled. But
the Simple Pairing process can only be used if both sides have the
support enabled in the host stack.

Add hci_conn_ssp_enabled() for hci_conn in HCI_EV_IO_CAPA_REQUEST and
HCI_EV_SIMPLE_PAIR_COMPLETE event handlers to fix the problem.

Fixes: 0493684ed239 ("[Bluetooth] Disable disconnect timer during Simple Pairing")
Signed-off-by: Ziyang Xuan 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: hci_sync: always check if connection is alive before deleting

2023-10-11T18:16:46+00:00

In hci_abort_conn_sync it is possible that conn is deleted concurrently
by something else, also e.g. when waiting for hdev->lock.  This causes
double deletion of the conn, so UAF or conn_hash.list corruption.

Fix by having all code paths check that the connection is still in
conn_hash before deleting it, while holding hdev->lock which prevents
any races.

Log (when powering off while BAP streaming, occurs rarely):
=======================================================================
kernel BUG at lib/list_debug.c:56!
...
 ? __list_del_entry_valid (lib/list_debug.c:56)
 hci_conn_del (net/bluetooth/hci_conn.c:154) bluetooth
 hci_abort_conn_sync (net/bluetooth/hci_sync.c:5415) bluetooth
 ? __pfx_hci_abort_conn_sync+0x10/0x10 [bluetooth]
 ? lock_release+0x1d5/0x3c0
 ? hci_disconnect_all_sync.constprop.0+0xb2/0x230 [bluetooth]
 ? __pfx_lock_release+0x10/0x10
 ? __kmem_cache_free+0x14d/0x2e0
 hci_disconnect_all_sync.constprop.0+0xda/0x230 [bluetooth]
 ? __pfx_hci_disconnect_all_sync.constprop.0+0x10/0x10 [bluetooth]
 ? hci_clear_adv_sync+0x14f/0x170 [bluetooth]
 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth]
 hci_set_powered_sync+0x293/0x450 [bluetooth]
=======================================================================

Fixes: 94d9ba9f9888 ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync")
Signed-off-by: Pauli Virtanen 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: Reject connection with the device which has same BD_ADDR

2023-10-11T18:16:24+00:00

This change is used to relieve CVE-2020-26555. The description of
the CVE:

Bluetooth legacy BR/EDR PIN code pairing in Bluetooth Core Specification
1.0B through 5.2 may permit an unauthenticated nearby device to spoof
the BD_ADDR of the peer device to complete pairing without knowledge
of the PIN. [1]

The detail of this attack is in IEEE paper:
BlueMirror: Reflections on Bluetooth Pairing and Provisioning Protocols
[2]

It's a reflection attack. The paper mentioned that attacker can induce
the attacked target to generate null link key (zero key) without PIN
code. In BR/EDR, the key generation is actually handled in the controller
which is below HCI.

A condition of this attack is that attacker should change the
BR_ADDR of his hacking device (Host B) to equal to the BR_ADDR with
the target device being attacked (Host A).

Thus, we reject the connection with device which has same BD_ADDR
both on HCI_Create_Connection and HCI_Connection_Request to prevent
the attack. A similar implementation also shows in btstack project.
[3][4]

Cc: stable@vger.kernel.org
Link: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26555 [1]
Link: https://ieeexplore.ieee.org/abstract/document/9474325/authors#authors [2]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3523 [3]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L7297 [4]
Signed-off-by: Lee, Chun-Yi 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: hci_event: Ignore NULL link key

2023-10-11T18:16:02+00:00

This change is used to relieve CVE-2020-26555. The description of the
CVE:

Bluetooth legacy BR/EDR PIN code pairing in Bluetooth Core Specification
1.0B through 5.2 may permit an unauthenticated nearby device to spoof
the BD_ADDR of the peer device to complete pairing without knowledge
of the PIN. [1]

The detail of this attack is in IEEE paper:
BlueMirror: Reflections on Bluetooth Pairing and Provisioning Protocols
[2]

It's a reflection attack. The paper mentioned that attacker can induce
the attacked target to generate null link key (zero key) without PIN
code. In BR/EDR, the key generation is actually handled in the controller
which is below HCI.

Thus, we can ignore null link key in the handler of "Link Key Notification
event" to relieve the attack. A similar implementation also shows in
btstack project. [3]

v3: Drop the connection when null link key be detected.

v2:
- Used Link: tag instead of Closes:
- Used bt_dev_dbg instead of BT_DBG
- Added Fixes: tag

Cc: stable@vger.kernel.org
Fixes: 55ed8ca10f35 ("Bluetooth: Implement link key handling for the management interface")
Link: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26555 [1]
Link: https://ieeexplore.ieee.org/abstract/document/9474325/authors#authors [2]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3722 [3]
Signed-off-by: Lee, Chun-Yi 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: ISO: Fix invalid context error

2023-10-11T18:15:40+00:00

This moves the hci_le_terminate_big_sync call from rx_work
to cmd_sync_work, to avoid calling sleeping function from
an invalid context.

Reported-by: syzbot+c715e1bd8dfbcb1ab176@syzkaller.appspotmail.com
Fixes: a0bfde167b50 ("Bluetooth: ISO: Add support for connecting multiple BISes")
Signed-off-by: Iulia Tanasescu 
Signed-off-by: Luiz Augusto von Dentz