Bluetooth: Fix SMP error and response to be mutually exclusive

Returning failure from the SMP data parsing function will cause an
immediate disconnect, making any attempts to send a response PDU futile.
This patch updates the function to always either send a response or
return an error, but never both at the same time:

* In the case that HCI_LE_ENABLED is not set we want to send a Pairing Not
  Supported response but it is not required to force a disconnection, so
  do not set the error return in this case.

* If we get garbage SMP data we can just fail with the handler function
  instead of also trying to send an SMP Failure PDU.

* There's no reason to force a disconnection if we receive an unknown SMP
  command. Instead simply send a proper Command Not Supported SMP
  response.

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

1 files changed, 5 insertions, 8 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 496584921fdc..16c181181775 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -1430,7 +1430,6 @@ static int smp_sig_channel(struct l2cap_chan *chan, struct sk_buff *skb)
                 return -EILSEQ;
 
         if (!test_bit(HCI_LE_ENABLED, &hcon->hdev->dev_flags)) {
-                err = -EOPNOTSUPP;
                 reason = SMP_PAIRING_NOTSUPP;
                 goto done;
         }
@@ -1447,7 +1446,6 @@ static int smp_sig_channel(struct l2cap_chan *chan, struct sk_buff *skb)
         if (code != SMP_CMD_PAIRING_REQ && code != SMP_CMD_SECURITY_REQ &&
             !test_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags)) {
                 BT_ERR("Unexpected SMP command 0x%02x. Disconnecting.", code);
-                reason = SMP_CMD_NOTSUPP;
                 err = -EOPNOTSUPP;
                 goto done;
         }
@@ -1459,7 +1457,6 @@ static int smp_sig_channel(struct l2cap_chan *chan, struct sk_buff *skb)
 
         case SMP_CMD_PAIRING_FAIL:
                 smp_failure(conn, 0);
-                reason = 0;
                 err = -EPERM;
                 break;
 
@@ -1501,17 +1498,17 @@ static int smp_sig_channel(struct l2cap_chan *chan, struct sk_buff *skb)
 
         default:
                 BT_DBG("Unknown command code 0x%2.2x", code);
-
                 reason = SMP_CMD_NOTSUPP;
-                err = -EOPNOTSUPP;
                 goto done;
         }
 
 done:
-        if (reason)
-                smp_failure(conn, reason);
-        if (!err)
+        if (!err) {
+                if (reason)
+                        smp_failure(conn, reason);
                 kfree_skb(skb);
+        }
+
         return err;
 }