Bluetooth: Implement deferred sco socket setup

In order to authenticate and configure an incoming SCO connection, the
BT_DEFER_SETUP option was added. This option is intended to defer reply
to Connect Request on SCO sockets.
When a connection is requested, the listening socket is unblocked but
the effective connection setup happens only on first recv. Any send
between accept and recv fails with -ENOTCONN.

Signed-off-by: Frédéric Dalleau <frederic.dalleau@linux.intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

1 files changed, 32 insertions, 3 deletions

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index c6678f2bffc9..eea17cdcaf7f 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -397,6 +397,7 @@ static void sco_sock_init(struct sock *sk, struct sock *parent)
 
         if (parent) {
                 sk->sk_type = parent->sk_type;
+                bt_sk(sk)->flags = bt_sk(parent)->flags;
                 security_sk_clone(parent, sk);
         }
 }
@@ -662,6 +663,28 @@ static int sco_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
         return err;
 }
 
+static int sco_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
+                            struct msghdr *msg, size_t len, int flags)
+{
+        struct sock *sk = sock->sk;
+        struct sco_pinfo *pi = sco_pi(sk);
+
+        lock_sock(sk);
+
+        if (sk->sk_state == BT_CONNECT2 &&
+            test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {
+                hci_conn_accept(pi->conn->hcon, 0);
+                sk->sk_state = BT_CONFIG;
+
+                release_sock(sk);
+                return 0;
+        }
+
+        release_sock(sk);
+
+        return bt_sock_recvmsg(iocb, sock, msg, len, flags);
+}
+
 static int sco_sock_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
 {
         struct sock *sk = sock->sk;
@@ -906,7 +929,10 @@ static void sco_conn_ready(struct sco_conn *conn)
                 hci_conn_hold(conn->hcon);
                 __sco_chan_add(conn, sk, parent);
 
-                sk->sk_state = BT_CONNECTED;
+                if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
+                        sk->sk_state = BT_CONNECT2;
+                else
+                        sk->sk_state = BT_CONNECTED;
 
                 /* Wake up parent */
                 parent->sk_data_ready(parent, 1);
@@ -919,7 +945,7 @@ done:
 }
 
 /* ----- SCO interface with lower layer (HCI) ----- */
-int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr)
+int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
 {
         struct sock *sk;
         struct hlist_node *node;
@@ -936,6 +962,9 @@ int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr)
                 if (!bacmp(&bt_sk(sk)->src, &hdev->bdaddr) ||
                     !bacmp(&bt_sk(sk)->src, BDADDR_ANY)) {
                         lm |= HCI_LM_ACCEPT;
+
+                        if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags))
+                                *flags |= HCI_PROTO_DEFER;
                         break;
                 }
         }
@@ -1024,7 +1053,7 @@ static const struct proto_ops sco_sock_ops = {
         .accept         = sco_sock_accept,
         .getname        = sco_sock_getname,
         .sendmsg        = sco_sock_sendmsg,
-        .recvmsg        = bt_sock_recvmsg,
+        .recvmsg        = sco_sock_recvmsg,
         .poll           = bt_sock_poll,
         .ioctl          = bt_sock_ioctl,
         .mmap           = sock_no_mmap,