1 files changed, 52 insertions, 2 deletions

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 07d0ba35b9a..5f55aef63e2 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1022,8 +1022,44 @@ struct link_key *hci_find_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
         return NULL;
 }
 
-int hci_add_link_key(struct hci_dev *hdev, int new_key, bdaddr_t *bdaddr,
-                                                u8 *val, u8 type, u8 pin_len)
+static int hci_persistent_key(struct hci_dev *hdev, struct hci_conn *conn,
+                                                u8 key_type, u8 old_key_type)
+{
+        /* Legacy key */
+        if (key_type < 0x03)
+                return 1;
+
+        /* Debug keys are insecure so don't store them persistently */
+        if (key_type == HCI_LK_DEBUG_COMBINATION)
+                return 0;
+
+        /* Changed combination key and there's no previous one */
+        if (key_type == HCI_LK_CHANGED_COMBINATION && old_key_type == 0xff)
+                return 0;
+
+        /* Security mode 3 case */
+        if (!conn)
+                return 1;
+
+        /* Neither local nor remote side had no-bonding as requirement */
+        if (conn->auth_type > 0x01 && conn->remote_auth > 0x01)
+                return 1;
+
+        /* Local side had dedicated bonding as requirement */
+        if (conn->auth_type == 0x02 || conn->auth_type == 0x03)
+                return 1;
+
+        /* Remote side had dedicated bonding as requirement */
+        if (conn->remote_auth == 0x02 || conn->remote_auth == 0x03)
+                return 1;
+
+        /* If none of the above criteria match, then don't store the key
+         * persistently */
+        return 0;
+}
+
+int hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn, int new_key,
+                                bdaddr_t *bdaddr, u8 *val, u8 type, u8 pin_len)
 {
         struct link_key *key, *old_key;
         u8 old_key_type;
@@ -1042,6 +1078,20 @@ int hci_add_link_key(struct hci_dev *hdev, int new_key, bdaddr_t *bdaddr,
 
         BT_DBG("%s key for %s type %u", hdev->name, batostr(bdaddr), type);
 
+        /* Some buggy controller combinations generate a changed
+         * combination key for legacy pairing even when there's no
+         * previous key */
+        if (type == HCI_LK_CHANGED_COMBINATION &&
+                                        (!conn || conn->remote_auth == 0xff) &&
+                                        old_key_type == 0xff)
+                type = HCI_LK_COMBINATION;
+
+        if (new_key && !hci_persistent_key(hdev, conn, type, old_key_type)) {
+                list_del(&key->list);
+                kfree(key);
+                return 0;
+        }
+
         bacpy(&key->bdaddr, bdaddr);
         memcpy(key->val, val, 16);
         key->type = type;