[PATCH] Bluetooth: Fix outgoing authentication requirement check

[PATCH] Bluetooth: Fix outgoing authentication requirement check

[johan.hedberg]

From: Johan Hedberg <johan.hedberg@intel.com>

The check for HIGH security level dates back to pre-mgmt times when a
raw L2CAP socket with HIGH security level was used to trigger dedicated
bonding. For legacy pairing checking for the security level was the only
way to catch the need to authenticate in all scenarios. With mgmt
however, the pair_device command does not use HIGH security but MEDIUM
security. Therefore, the existing code would never trigger
authentication for a non-SSP connection without an MITM requirement
(e.g. if user space provided a NoInputNoOutput IO capability). In such a
scenario the mgmt_pair_device command would return success without
actually triggering any kind of pairing.

This patch updates the authentication requirement check to also consider
MEDIUM security level, and thereby ensures that mgmt_pair_device will
always trigger authentication.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
This one should probably get a Cc: stable flag. It's also a
pre-requisite for the first mgmt-tester pairing test case that was
recently added to user space git.

 net/bluetooth/hci_event.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 5f812455a450..cfcce448957b 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1185,9 +1185,12 @@ static int hci_outgoing_auth_needed(struct hci_dev *hdev,
 		return 0;
 
 	/* Only request authentication for SSP connections or non-SSP
-	 * devices with sec_level HIGH or if MITM protection is requested */
+	 * devices with sec_level MEDIUM or HIGH or if MITM protection
+	 * is requested.
+	 */
 	if (!hci_conn_ssp_enabled(conn) && !(conn->auth_type & 0x01) &&
-	    conn->pending_sec_level != BT_SECURITY_HIGH)
+	    conn->pending_sec_level != BT_SECURITY_HIGH &&
+	    conn->pending_sec_level != BT_SECURITY_MEDIUM)
 		return 0;
 
 	return 1;
-- 
1.8.4.2

Re: [PATCH] Bluetooth: Fix outgoing authentication requirement check

[Marcel Holtmann]

Hi Johan,

> The check for HIGH security level dates back to pre-mgmt times when a
> raw L2CAP socket with HIGH security level was used to trigger dedicated
> bonding. For legacy pairing checking for the security level was the only
> way to catch the need to authenticate in all scenarios. With mgmt
> however, the pair_device command does not use HIGH security but MEDIUM
> security. Therefore, the existing code would never trigger
> authentication for a non-SSP connection without an MITM requirement
> (e.g. if user space provided a NoInputNoOutput IO capability). In such a
> scenario the mgmt_pair_device command would return success without
> actually triggering any kind of pairing.
> 
> This patch updates the authentication requirement check to also consider
> MEDIUM security level, and thereby ensures that mgmt_pair_device will
> always trigger authentication.
> 
> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
> ---
> This one should probably get a Cc: stable flag. It's also a
> pre-requisite for the first mgmt-tester pairing test case that was
> recently added to user space git.
> 
> net/bluetooth/hci_event.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)

patch has been applied to bluetooth-next tree.

I want to give this some time to get tested via bluetooth-next before we mark this as to be backported to stable.

Regards

Marcel