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[0/2] Bluetooth: ignore NULL link key and reject connection

Message ID 20231001074524.GA14361@linux-691t
Headers
Series Bluetooth: ignore NULL link key and reject connection |

Message

Lee, Chun-Yi Oct. 1, 2023, 7:45 a.m. UTC 
  with the device which has same BD_ADDR
 
This patch set 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. And, 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). So we reject
the connection with device which has same BD_ADDR both on HCI_Create_Connection
and HCI_Connection_Request to prevent the attack.

Similar implementations also show in btstack project. [3][4][5]

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]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3523 [4]
Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L7297 [5]

Lee, Chun-Yi (2):
  Bluetooth: hci_event: Ignore NULL link key
  Bluetooth: Reject connection with the device which has same BD_ADDR

 net/bluetooth/hci_conn.c  |  7 +++++++
 net/bluetooth/hci_event.c | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

Comments

Lee, Chun-Yi Oct. 1, 2023, 8:05 a.m. UTC | #1 
Hi experts,

On Sun, Oct 01, 2023 at 03:45:24PM +0800, Lee, Chun-Yi wrote:
> with the device which has same BD_ADDR
>  
> This patch set 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. And, 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). So we reject
> the connection with device which has same BD_ADDR both on HCI_Create_Connection
> and HCI_Connection_Request to prevent the attack.
> 
> Similar implementations also show in btstack project. [3][4][5]
> 
> 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]
> Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3523 [4]
> Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L7297 [5]
> 
> Lee, Chun-Yi (2):
>   Bluetooth: hci_event: Ignore NULL link key
>   Bluetooth: Reject connection with the device which has same BD_ADDR
> 
>  net/bluetooth/hci_conn.c  |  7 +++++++
>  net/bluetooth/hci_event.c | 16 ++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> -- 
> 2.35.3
> 
> >From 2c6cd3f353d21086a3163a9ad461789d203a7ee4 Mon Sep 17 00:00:00 2001
> From: "Lee, Chun-Yi" <jlee@suse.com>
> Date: Sat, 30 Sep 2023 16:56:56 +0800
> Subject: [PATCH 0/2] Bluetooth: ignore NULL link key and reject connection 
> with the device which has same BD_ADDR
>  

Please ignore this patch set because I used wrong mutt command to send out
patch. It causes that the mail has duplicate contents. I will send out a
new series.

Sorry for any inconvenience caused!

Joey Lee

> This patch set 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. And, 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). So we reject
> the connection with device which has same BD_ADDR both on HCI_Create_Connection
> and HCI_Connection_Request to prevent the attack.
> 
> Similar implementations also show in btstack project. [3][4][5]
> 
> 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]
> Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L3523 [4]
> Link: https://github.com/bluekitchen/btstack/blob/master/src/hci.c#L7297 [5]
> 
> Lee, Chun-Yi (2):
>   Bluetooth: hci_event: Ignore NULL link key
>   Bluetooth: Reject connection with the device which has same BD_ADDR
> 
>  net/bluetooth/hci_conn.c  |  7 +++++++
>  net/bluetooth/hci_event.c | 16 ++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> -- 
> 2.35.3