[PATCH v2 0/3] Bluetooth: Various L2CAP fixes

[PATCH v2 0/3] Bluetooth: Various L2CAP fixes

[johan.hedberg]

Hi,

This one contains a fix for the locking bug spotted by Lizardo in patch
3/3 as well as the minor coding style issue in the same patch.

Johan

----------------------------------------------------------------
Johan Hedberg (3):
      Bluetooth: Fix L2CAP Disconnect response for unknown CID
      Bluetooth: Fix responding to invalid L2CAP signaling commands
      Bluetooth: Fix waiting for clearing of BT_SK_SUSPEND flag

 include/net/bluetooth/bluetooth.h |  1 +
 net/bluetooth/af_bluetooth.c      | 39 +++++++++++++++++++++++++++++++++++++
 net/bluetooth/l2cap_core.c        | 10 +++++++++-
 net/bluetooth/l2cap_sock.c        |  6 ++++++
 net/bluetooth/rfcomm/sock.c       |  9 +++++++--
 5 files changed, 62 insertions(+), 3 deletions(-)

[PATCH v2 1/3] Bluetooth: Fix L2CAP Disconnect response for unknown CID

[johan.hedberg]

From: Johan Hedberg <johan.hedberg@intel.com>

If we receive an L2CAP Disconnect Request for an unknown CID we should
not just silently drop it but reply with a proper Command Reject
response. This patch fixes this by ensuring that the disconnect handler
returns a proper error instead of 0 and will cause the function caller
to send the right response.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
v2: no changes

 net/bluetooth/l2cap_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index b3bb7bc..ea3792f 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4206,7 +4206,7 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn,
 	chan = __l2cap_get_chan_by_scid(conn, dcid);
 	if (!chan) {
 		mutex_unlock(&conn->chan_lock);
-		return 0;
+		return -EINVAL;
 	}
 
 	l2cap_chan_lock(chan);
-- 
1.8.4.rc3

[PATCH v2 2/3] Bluetooth: Fix responding to invalid L2CAP signaling commands

[johan.hedberg]

From: Johan Hedberg <johan.hedberg@intel.com>

When we have an LE link we should not respond to any data on the BR/EDR
L2CAP signaling channel (0x0001) and vice-versa when we have a BR/EDR
link we should not respond to LE L2CAP (CID 0x0005) signaling commands.
This patch fixes this issue by checking for a valid link type and
ignores data if it is wrong.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
v2: no changes

 net/bluetooth/l2cap_core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ea3792f..1d03644 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -5297,6 +5297,7 @@ static inline int l2cap_le_sig_cmd(struct l2cap_conn *conn,
 static inline void l2cap_le_sig_channel(struct l2cap_conn *conn,
 					struct sk_buff *skb)
 {
+	struct hci_conn *hcon = conn->hcon;
 	u8 *data = skb->data;
 	int len = skb->len;
 	struct l2cap_cmd_hdr cmd;
@@ -5304,6 +5305,9 @@ static inline void l2cap_le_sig_channel(struct l2cap_conn *conn,
 
 	l2cap_raw_recv(conn, skb);
 
+	if (hcon->type != LE_LINK)
+		return;
+
 	while (len >= L2CAP_CMD_HDR_SIZE) {
 		u16 cmd_len;
 		memcpy(&cmd, data, L2CAP_CMD_HDR_SIZE);
@@ -5342,6 +5346,7 @@ static inline void l2cap_le_sig_channel(struct l2cap_conn *conn,
 static inline void l2cap_sig_channel(struct l2cap_conn *conn,
 				     struct sk_buff *skb)
 {
+	struct hci_conn *hcon = conn->hcon;
 	u8 *data = skb->data;
 	int len = skb->len;
 	struct l2cap_cmd_hdr cmd;
@@ -5349,6 +5354,9 @@ static inline void l2cap_sig_channel(struct l2cap_conn *conn,
 
 	l2cap_raw_recv(conn, skb);
 
+	if (hcon->type != ACL_LINK)
+		return;
+
 	while (len >= L2CAP_CMD_HDR_SIZE) {
 		u16 cmd_len;
 		memcpy(&cmd, data, L2CAP_CMD_HDR_SIZE);
-- 
1.8.4.rc3

[PATCH v2 3/3] Bluetooth: Fix waiting for clearing of BT_SK_SUSPEND flag

[johan.hedberg]

From: Johan Hedberg <johan.hedberg@intel.com>

In the case of blocking sockets we should not proceed with sendmsg() if
the socket has the BT_SK_SUSPEND flag set. So far the code was only
ensuring that POLLOUT doesn't get set for non-blocking sockets using
poll() but there was no code in place to ensure that blocking sockets do
the right thing when writing to them.

This patch adds a new bt_sock_wait_unsuspend helper function to sleep in
the sendmsg call if the BT_SK_SUSPEND flag is set, and wake up as soon
as it is unset. It also updates the L2CAP and RFCOMM sendmsg callbacks
to take advantage of this new helper function.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
---
v2: Fix missing release_sock() in rfcomm_sock_sendmsg()

 include/net/bluetooth/bluetooth.h |  1 +
 net/bluetooth/af_bluetooth.c      | 39 +++++++++++++++++++++++++++++++++++++++
 net/bluetooth/l2cap_sock.c        |  6 ++++++
 net/bluetooth/rfcomm/sock.c       |  9 +++++++--
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 10d43d8..3299d42 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -249,6 +249,7 @@ int  bt_sock_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 uint bt_sock_poll(struct file *file, struct socket *sock, poll_table *wait);
 int  bt_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
 int  bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo);
+int  bt_sock_wait_unsuspend(struct sock *sk, unsigned long flags);
 
 void bt_accept_enqueue(struct sock *parent, struct sock *sk);
 void bt_accept_unlink(struct sock *sk);
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 9096137..6081e78 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -525,6 +525,45 @@ int bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo)
 }
 EXPORT_SYMBOL(bt_sock_wait_state);
 
+int bt_sock_wait_unsuspend(struct sock *sk, unsigned long flags)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	unsigned long timeo;
+	int err = 0;
+
+	BT_DBG("sk %p", sk);
+
+	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (test_bit(BT_SK_SUSPEND, &bt_sk(sk)->flags)) {
+		if (!timeo) {
+			err = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			err = sock_intr_errno(timeo);
+			break;
+		}
+
+		release_sock(sk);
+		timeo = schedule_timeout(timeo);
+		lock_sock(sk);
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		err = sock_error(sk);
+		if (err)
+			break;
+	}
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(sk_sleep(sk), &wait);
+
+	return err;
+}
+EXPORT_SYMBOL(bt_sock_wait_unsuspend);
+
 #ifdef CONFIG_PROC_FS
 struct bt_seq_state {
 	struct bt_sock_list *l;
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 0098af8..1ddbc1a 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -777,6 +777,12 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 	if (sk->sk_state != BT_CONNECTED)
 		return -ENOTCONN;
 
+	lock_sock(sk);
+	err = bt_sock_wait_unsuspend(sk, msg->msg_flags);
+	release_sock(sk);
+	if (err)
+		return err;
+
 	l2cap_chan_lock(chan);
 	err = l2cap_chan_send(chan, msg, len, sk->sk_priority);
 	l2cap_chan_unlock(chan);
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 30b3721..7a48cfb 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -544,7 +544,7 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 	struct sock *sk = sock->sk;
 	struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
 	struct sk_buff *skb;
-	int sent = 0;
+	int err, sent = 0;
 
 	if (test_bit(RFCOMM_DEFER_SETUP, &d->flags))
 		return -ENOTCONN;
@@ -559,9 +559,14 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 
 	lock_sock(sk);
 
+	err = bt_sock_wait_unsuspend(sk, msg->msg_flags);
+	if (err) {
+		release_sock(sk);
+		return err;
+	}
+
 	while (len) {
 		size_t size = min_t(size_t, len, d->mtu);
-		int err;
 
 		skb = sock_alloc_send_skb(sk, size + RFCOMM_SKB_RESERVE,
 				msg->msg_flags & MSG_DONTWAIT, &err);
-- 
1.8.4.rc3