[Bluetooth] Enforce security for outgoing RFCOMM connections

Recent tests with various Bluetooth headsets have shown that some of
them don't enforce authentication and encryption when connecting. All
of them leave it up to the host stack to enforce it. Non of them should
allow unencrypted connections, but that is how it is. So in case the
link mode settings require authentication and/or encryption it will now
also be enforced on outgoing RFCOMM connections. Previously this was
only done for incoming connections.

This support has a small drawback from a protocol level point of view
since the host stack can't really tell with 100% certainty if a remote
side is already authenticated or not. So if both sides are configured
to enforce authentication it will be requested twice. Most Bluetooth
chips are caching this information and thus no extra authentication
procedure has to be triggered over-the-air, but it can happen.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/include/net/bluetooth/rfcomm.h b/include/net/bluetooth/rfcomm.h
index 98ec7a3206899cb7aff544cc69a355a592436698..8c54ff37ad4fb5a50b7c68d5e0817a9de5938317 100644 (file)
--- a/include/net/bluetooth/rfcomm.h
+++ b/include/net/bluetooth/rfcomm.h
@@ -181,6 +181,7 @@ struct rfcomm_dlc {
        u8            priority;
        u8            v24_sig;
        u8            mscex;
+       u8            out;
 
        u32           link_mode;
 

diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index 0c2c93735e935417314e30eddbadc017222612ba..1f92f9ab495935f89476da32e06119abd9695a85 100644 (file)
--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -53,7 +53,7 @@
 #define BT_DBG(D...)
 #endif
 
-#define VERSION "1.8"
+#define VERSION "1.9"
 
 static int disable_cfc = 0;
 static int channel_mtu = -1;
@@ -230,6 +230,21 @@ static int rfcomm_l2sock_create(struct socket **sock)
        return err;
 }
 
+static inline int rfcomm_check_link_mode(struct rfcomm_dlc *d)
+{
+       struct sock *sk = d->session->sock->sk;
+
+       if (d->link_mode & (RFCOMM_LM_ENCRYPT | RFCOMM_LM_SECURE)) {
+               if (!hci_conn_encrypt(l2cap_pi(sk)->conn->hcon))
+                       return 1;
+       } else if (d->link_mode & RFCOMM_LM_AUTH) {
+               if (!hci_conn_auth(l2cap_pi(sk)->conn->hcon))
+                       return 1;
+       }
+
+       return 0;
+}
+
 /* ---- RFCOMM DLCs ---- */
 static void rfcomm_dlc_timeout(unsigned long arg)
 {
@@ -371,15 +386,23 @@ static int __rfcomm_dlc_open(struct rfcomm_dlc *d, bdaddr_t *src, bdaddr_t *dst,
        d->addr     = __addr(s->initiator, dlci);
        d->priority = 7;
 
-       d->state    = BT_CONFIG;
+       d->state = BT_CONFIG;
        rfcomm_dlc_link(s, d);
 
+       d->out = 1;
+
        d->mtu = s->mtu;
        d->cfc = (s->cfc == RFCOMM_CFC_UNKNOWN) ? 0 : s->cfc;
 
-       if (s->state == BT_CONNECTED)
-               rfcomm_send_pn(s, 1, d);
+       if (s->state == BT_CONNECTED) {
+               if (rfcomm_check_link_mode(d))
+                       set_bit(RFCOMM_AUTH_PENDING, &d->flags);
+               else
+                       rfcomm_send_pn(s, 1, d);
+       }
+
        rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
+
        return 0;
 }
 
@@ -1146,21 +1169,6 @@ static int rfcomm_recv_disc(struct rfcomm_session *s, u8 dlci)
        return 0;
 }
 
-static inline int rfcomm_check_link_mode(struct rfcomm_dlc *d)
-{
-       struct sock *sk = d->session->sock->sk;
-
-       if (d->link_mode & (RFCOMM_LM_ENCRYPT | RFCOMM_LM_SECURE)) {
-               if (!hci_conn_encrypt(l2cap_pi(sk)->conn->hcon))
-                       return 1;
-       } else if (d->link_mode & RFCOMM_LM_AUTH) {
-               if (!hci_conn_auth(l2cap_pi(sk)->conn->hcon))
-                       return 1;
-       }
-
-       return 0;
-}
-
 static void rfcomm_dlc_accept(struct rfcomm_dlc *d)
 {
        struct sock *sk = d->session->sock->sk;
@@ -1205,10 +1213,8 @@ static int rfcomm_recv_sabm(struct rfcomm_session *s, u8 dlci)
                        if (rfcomm_check_link_mode(d)) {
                                set_bit(RFCOMM_AUTH_PENDING, &d->flags);
                                rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
-                               return 0;
-                       }
-
-                       rfcomm_dlc_accept(d);
+                       } else
+                               rfcomm_dlc_accept(d);
                }
                return 0;
        }
@@ -1223,10 +1229,8 @@ static int rfcomm_recv_sabm(struct rfcomm_session *s, u8 dlci)
                if (rfcomm_check_link_mode(d)) {
                        set_bit(RFCOMM_AUTH_PENDING, &d->flags);
                        rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
-                       return 0;
-               }
-
-               rfcomm_dlc_accept(d);
+               } else
+                       rfcomm_dlc_accept(d);
        } else {
                rfcomm_send_dm(s, dlci);
        }
@@ -1636,7 +1640,11 @@ static void rfcomm_process_connect(struct rfcomm_session *s)
                d = list_entry(p, struct rfcomm_dlc, list);
                if (d->state == BT_CONFIG) {
                        d->mtu = s->mtu;
-                       rfcomm_send_pn(s, 1, d);
+                       if (rfcomm_check_link_mode(d)) {
+                               set_bit(RFCOMM_AUTH_PENDING, &d->flags);
+                               rfcomm_dlc_set_timer(d, RFCOMM_AUTH_TIMEOUT);
+                       } else
+                               rfcomm_send_pn(s, 1, d);
                }
        }
 }
@@ -1709,7 +1717,11 @@ static inline void rfcomm_process_dlcs(struct rfcomm_session *s)
 
                if (test_and_clear_bit(RFCOMM_AUTH_ACCEPT, &d->flags)) {
                        rfcomm_dlc_clear_timer(d);
-                       rfcomm_dlc_accept(d);
+                       if (d->out) {
+                               rfcomm_send_pn(s, 1, d);
+                               rfcomm_dlc_set_timer(d, RFCOMM_CONN_TIMEOUT);
+                       } else
+                               rfcomm_dlc_accept(d);
                        if (d->link_mode & RFCOMM_LM_SECURE) {
                                struct sock *sk = s->sock->sk;
                                hci_conn_change_link_key(l2cap_pi(sk)->conn->hcon);
@@ -1717,7 +1729,10 @@ static inline void rfcomm_process_dlcs(struct rfcomm_session *s)
                        continue;
                } else if (test_and_clear_bit(RFCOMM_AUTH_REJECT, &d->flags)) {
                        rfcomm_dlc_clear_timer(d);
-                       rfcomm_send_dm(s, d->dlci);
+                       if (!d->out)
+                               rfcomm_send_dm(s, d->dlci);
+                       else
+                               d->state = BT_CLOSED;
                        __rfcomm_dlc_close(d, ECONNREFUSED);
                        continue;
                }
@@ -1726,7 +1741,7 @@ static inline void rfcomm_process_dlcs(struct rfcomm_session *s)
                        continue;
 
                if ((d->state == BT_CONNECTED || d->state == BT_DISCONN) &&
-                               d->mscex == RFCOMM_MSCEX_OK)
+                                               d->mscex == RFCOMM_MSCEX_OK)
                        rfcomm_process_tx(d);
        }
 }

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 5083adcbfae5b57fbf912ade3bb4e122b4c7d759..cacb1ab51f997e105c2495f9222140a5fc2ffd67 100644 (file)
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -309,13 +309,13 @@ static struct sock *rfcomm_sock_alloc(struct net *net, struct socket *sock, int
        sk->sk_destruct = rfcomm_sock_destruct;
        sk->sk_sndtimeo = RFCOMM_CONN_TIMEOUT;
 
-       sk->sk_sndbuf   = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
-       sk->sk_rcvbuf   = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
+       sk->sk_sndbuf = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
+       sk->sk_rcvbuf = RFCOMM_MAX_CREDITS * RFCOMM_DEFAULT_MTU * 10;
 
        sock_reset_flag(sk, SOCK_ZAPPED);
 
        sk->sk_protocol = proto;
-       sk->sk_state    = BT_OPEN;
+       sk->sk_state    = BT_OPEN;
 
        bt_sock_link(&rfcomm_sk_list, sk);
 
@@ -413,6 +413,8 @@ static int rfcomm_sock_connect(struct socket *sock, struct sockaddr *addr, int a
        bacpy(&bt_sk(sk)->dst, &sa->rc_bdaddr);
        rfcomm_pi(sk)->channel = sa->rc_channel;
 
+       d->link_mode = rfcomm_pi(sk)->link_mode;
+
        err = rfcomm_dlc_open(d, &bt_sk(sk)->src, &sa->rc_bdaddr, sa->rc_channel);
        if (!err)
                err = bt_sock_wait_state(sk, BT_CONNECTED,