Bluetooth: SMP: Fix not generating mackey and ltk when repairing
The change eed467b517e8 ("Bluetooth: fix passkey uninitialized when used")
introduced a goto that bypasses the creation of temporary mackey and ltk
which are later used by the likes of DHKey Check step.
Later ffee202a78c2 ("Bluetooth: Always request for user confirmation for
Just Works (LE SC)") which means confirm_hint is always set in case
JUST_WORKS so the branch checking for an existing LTK becomes pointless
as confirm_hint will always be set, so this just merge both cases of
malicious or legitimate devices to be confirmed before continuing with the
pairing procedure.
Link: https://github.com/bluez/bluez/issues/1622
Fixes: eed467b517e8 ("Bluetooth: fix passkey uninitialized when used")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 45512b2..3a1ce04 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -2136,7 +2136,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
struct smp_chan *smp = chan->data;
struct hci_conn *hcon = conn->hcon;
u8 *pkax, *pkbx, *na, *nb, confirm_hint;
- u32 passkey;
+ u32 passkey = 0;
int err;
bt_dev_dbg(hcon->hdev, "conn %p", conn);
@@ -2188,24 +2188,6 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd),
smp->prnd);
SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
-
- /* Only Just-Works pairing requires extra checks */
- if (smp->method != JUST_WORKS)
- goto mackey_and_ltk;
-
- /* If there already exists long term key in local host, leave
- * the decision to user space since the remote device could
- * be legitimate or malicious.
- */
- if (hci_find_ltk(hcon->hdev, &hcon->dst, hcon->dst_type,
- hcon->role)) {
- /* Set passkey to 0. The value can be any number since
- * it'll be ignored anyway.
- */
- passkey = 0;
- confirm_hint = 1;
- goto confirm;
- }
}
mackey_and_ltk:
@@ -2226,11 +2208,12 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
if (err)
return SMP_UNSPECIFIED;
- confirm_hint = 0;
-
-confirm:
- if (smp->method == JUST_WORKS)
- confirm_hint = 1;
+ /* Always require user confirmation for Just-Works pairing to prevent
+ * impersonation attacks, or in case of a legitimate device that is
+ * repairing use the confirmation as acknowledgment to proceed with the
+ * creation of new keys.
+ */
+ confirm_hint = smp->method == JUST_WORKS ? 1 : 0;
err = mgmt_user_confirm_request(hcon->hdev, &hcon->dst, hcon->type,
hcon->dst_type, passkey, confirm_hint);
