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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: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Mike Christie 2011-06-24 15:11:54 -05:00 committed by James Bottomley
parent f457a46f17
commit 03adb5f912
1 changed files with 41 additions and 20 deletions
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61
drivers/scsi/iscsi_tcp.c
View File

@ -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