[PATCH v1] Bluetooth: Check for encryption key size on connect

[PATCH v1] Bluetooth: Check for encryption key size on connect

[Archie Pusaka]

From: Archie Pusaka <apusaka@chromium.org>

When receiving connection, we only check whether the link has been
encrypted, but not the encryption key size of the link.

This patch adds check for encryption key size, and reject L2CAP
connection which size is below the specified threshold (default 7)
with security block.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>

---

 net/bluetooth/l2cap_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ade83e224567..b4fc0ad38aaa 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4101,7 +4101,8 @@ static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn,
 
 	/* Check if the ACL is secure enough (if not SDP) */
 	if (psm != cpu_to_le16(L2CAP_PSM_SDP) &&
-	    !hci_conn_check_link_mode(conn->hcon)) {
+	    (!hci_conn_check_link_mode(conn->hcon) ||
+	    !l2cap_check_enc_key_size(conn->hcon))) {
 		conn->disc_reason = HCI_ERROR_AUTH_FAILURE;
 		result = L2CAP_CR_SEC_BLOCK;
 		goto response;
-- 
2.28.0.681.g6f77f65b4e-goog

Re: [PATCH v1] Bluetooth: Check for encryption key size on connect

[Marcel Holtmann]

Hi Archie,

> When receiving connection, we only check whether the link has been
> encrypted, but not the encryption key size of the link.
> 
> This patch adds check for encryption key size, and reject L2CAP
> connection which size is below the specified threshold (default 7)
> with security block.

please include btmon trace in the commit message to demonstrate this.

Regards

Marcel