Bluetooth: Update LTK lookup to correctly deal with SC LTKs

LTKs derived from Secure Connections based pairing are symmetric, i.e.
they should match both master and slave role. This patch updates the LTK
lookup functions to ignore the desired role when dealing with SC LTKs.

Furthermore, with Secure Connections the EDiv and Rand values are not
used and should always be set to zero. This patch updates the LTK lookup
to first use the bdaddr as key and then do the necessary verifications
of EDiv and Rand based on whether the found LTK is for SC or not.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 2586e405adb373abdd4b2682f7b463dcd6a52dc3..e091e8ffeb8eab69b99e08f9cb7f0c5085d16d14 100644 (file)
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3195,11 +3195,18 @@ struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, __le64 rand,
                if (k->ediv != ediv || k->rand != rand)
                        continue;
 
-               if (ltk_role(k->type) != role)
-                       continue;
+               if (smp_ltk_is_sc(k)) {
+                       if (k->type == SMP_LTK_P256_DEBUG &&
+                           !test_bit(HCI_KEEP_DEBUG_KEYS, &hdev->dev_flags))
+                               continue;
+                       rcu_read_unlock();
+                       return k;
+               }
 
-               rcu_read_unlock();
-               return k;
+               if (ltk_role(k->type) == role) {
+                       rcu_read_unlock();
+                       return k;
+               }
        }
        rcu_read_unlock();
 
@@ -3213,9 +3220,18 @@ struct smp_ltk *hci_find_ltk_by_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
 
        rcu_read_lock();
        list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
-               if (addr_type == k->bdaddr_type &&
-                   bacmp(bdaddr, &k->bdaddr) == 0 &&
-                   ltk_role(k->type) == role) {
+               if (addr_type != k->bdaddr_type || bacmp(bdaddr, &k->bdaddr))
+                       continue;
+
+               if (smp_ltk_is_sc(k)) {
+                       if (k->type == SMP_LTK_P256_DEBUG &&
+                           !test_bit(HCI_KEEP_DEBUG_KEYS, &hdev->dev_flags))
+                               continue;
+                       rcu_read_unlock();
+                       return k;
+               }
+
+               if (ltk_role(k->type) == role) {
                        rcu_read_unlock();
                        return k;
                }

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index f980fc46ea5e55edd65320d2ea0c029fa63e9a9a..0058b545c5edc7364ab2b305c3d895405ad0229d 100644 (file)
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4590,10 +4590,21 @@ static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
        if (conn == NULL)
                goto not_found;
 
-       ltk = hci_find_ltk(hdev, ev->ediv, ev->rand, conn->role);
-       if (ltk == NULL)
+       ltk = hci_find_ltk_by_addr(hdev, &conn->dst, conn->dst_type,
+                                  conn->role);
+       if (!ltk)
                goto not_found;
 
+       if (smp_ltk_is_sc(ltk)) {
+               /* With SC both EDiv and Rand are set to zero */
+               if (ev->ediv || ev->rand)
+                       goto not_found;
+       } else {
+               /* For non-SC keys check that EDiv and Rand match */
+               if (ev->ediv != ltk->ediv || ev->rand != ltk->rand)
+                       goto not_found;
+       }
+
        memcpy(cp.ltk, ltk->val, sizeof(ltk->val));
        cp.handle = cpu_to_le16(conn->handle);