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Commit 03adb5f9 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
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[SCSI] iscsi_tcp: fix locking around iscsi sk user data 



iscsi_sw_tcp_conn_restore_callbacks could have set
the sk_user_data field to NULL then iscsi_sw_tcp_data_ready
could read that and try to access the NULL pointer. This
adds some checks for NULL sk_user_data in the sk
callback functions and it uses the sk_callback_lock to
set/get that sk_user_data field.

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent f457a46f

drivers/scsi/iscsi_tcp.c

+41 −20
Original line number Diff line number Diff line
@@ -107,10 +107,12 @@ static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, 
 * If the socket is in CLOSE or CLOSE_WAIT we should

 * not close the connection if there is still some

 * data pending.

 *

 * Must be called with sk_callback_lock.

 */

static inline int iscsi_sw_sk_state_check(struct sock *sk)

{

	struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;

	struct iscsi_conn *conn = sk->sk_user_data;



	if ((sk->sk_state == TCP_CLOSE_WAIT || sk->sk_state == TCP_CLOSE) &&

	    !atomic_read(&sk->sk_rmem_alloc)) {
@@ -123,11 +125,17 @@ static inline int iscsi_sw_sk_state_check(struct sock *sk) 


static void iscsi_sw_tcp_data_ready(struct sock *sk, int flag)

{

	struct iscsi_conn *conn = sk->sk_user_data;

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	struct iscsi_conn *conn;

	struct iscsi_tcp_conn *tcp_conn;

	read_descriptor_t rd_desc;



	read_lock(&sk->sk_callback_lock);

	conn = sk->sk_user_data;

	if (!conn) {

		read_unlock(&sk->sk_callback_lock);

		return;

	}

	tcp_conn = conn->dd_data;



	/*

	 * Use rd_desc to pass 'conn' to iscsi_tcp_recv.
@@ -141,11 +149,10 @@ static void iscsi_sw_tcp_data_ready(struct sock *sk, int flag) 


	iscsi_sw_sk_state_check(sk);



	read_unlock(&sk->sk_callback_lock);



	/* If we had to (atomically) map a highmem page,

	 * unmap it now. */

	iscsi_tcp_segment_unmap(&tcp_conn->in.segment);

	read_unlock(&sk->sk_callback_lock);

}



static void iscsi_sw_tcp_state_change(struct sock *sk)
@@ -157,8 +164,11 @@ static void iscsi_sw_tcp_state_change(struct sock *sk) 
	void (*old_state_change)(struct sock *);



	read_lock(&sk->sk_callback_lock);



	conn = (struct iscsi_conn*)sk->sk_user_data;

	conn = sk->sk_user_data;

	if (!conn) {

		read_unlock(&sk->sk_callback_lock);

		return;

	}

	session = conn->session;



	iscsi_sw_sk_state_check(sk);
@@ -178,11 +188,25 @@ static void iscsi_sw_tcp_state_change(struct sock *sk) 
 **/

static void iscsi_sw_tcp_write_space(struct sock *sk)

{

	struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;

	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

	struct iscsi_sw_tcp_conn *tcp_sw_conn = tcp_conn->dd_data;

	struct iscsi_conn *conn;

	struct iscsi_tcp_conn *tcp_conn;

	struct iscsi_sw_tcp_conn *tcp_sw_conn;

	void (*old_write_space)(struct sock *);



	read_lock_bh(&sk->sk_callback_lock);

	conn = sk->sk_user_data;

	if (!conn) {

		read_unlock_bh(&sk->sk_callback_lock);

		return;

	}



	tcp_conn = conn->dd_data;

	tcp_sw_conn = tcp_conn->dd_data;

	old_write_space = tcp_sw_conn->old_write_space;

	read_unlock_bh(&sk->sk_callback_lock);



	old_write_space(sk);



	tcp_sw_conn->old_write_space(sk);

	ISCSI_SW_TCP_DBG(conn, "iscsi_write_space\n");

	iscsi_conn_queue_work(conn);

}
@@ -592,20 +616,17 @@ static void iscsi_sw_tcp_conn_stop(struct iscsi_cls_conn *cls_conn, int flag) 
	/* userspace may have goofed up and not bound us */

	if (!sock)

		return;

	/*

	 * Make sure our recv side is stopped.

	 * Older tools called conn stop before ep_disconnect

	 * so IO could still be coming in.

	 */

	write_lock_bh(&tcp_sw_conn->sock->sk->sk_callback_lock);

	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);

	write_unlock_bh(&tcp_sw_conn->sock->sk->sk_callback_lock);



	sock->sk->sk_err = EIO;

	wake_up_interruptible(sk_sleep(sock->sk));



	iscsi_conn_stop(cls_conn, flag);

	/* stop xmit side */

	iscsi_suspend_tx(conn);



	/* stop recv side and release socket */

	iscsi_sw_tcp_release_conn(conn);



	iscsi_conn_stop(cls_conn, flag);

}



static int