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scsi: libiscsi: Teardown iscsi_cls_conn gracefully

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Commit 1b8d0300a3 ("scsi: libiscsi: Fix UAF in
iscsi_conn_get_param()/iscsi_conn_teardown()") fixed an UAF in
iscsi_conn_get_param() and introduced 2 tmp_xxx varibles.

We can gracefully fix this UAF with the help of device_del(). Calling
iscsi_remove_conn() at the beginning of iscsi_conn_teardown would make
userspace unable to see iscsi_cls_conn. This way we we can free memory
safely.

Remove iscsi_destroy_conn() since it is no longer used.

Link: https://lore.kernel.org/r/20220310015759.3296841-4-haowenchao@huawei.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
Signed-off-by: Wu Bo <wubo40@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Wenchao Hao 2022-03-09 20:57:59 -05:00 committed by Martin K. Petersen
parent 7dae459f5e
commit 8709c32309
3 changed files with 10 additions and 28 deletions
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10
drivers/scsi/libiscsi.c
View File

@ -3107,8 +3107,8 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
{
struct iscsi_conn *conn = cls_conn->dd_data;
struct iscsi_session *session = conn->session;
char *tmp_persistent_address = conn->persistent_address;
char *tmp_local_ipaddr = conn->local_ipaddr;
iscsi_remove_conn(cls_conn);
del_timer_sync(&conn->transport_timer);
@ -3130,6 +3130,8 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
spin_lock_bh(&session->frwd_lock);
free_pages((unsigned long) conn->data,
get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
kfree(conn->persistent_address);
kfree(conn->local_ipaddr);
/* regular RX path uses back_lock */
spin_lock_bh(&session->back_lock);
kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
@ -3140,9 +3142,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
spin_unlock_bh(&session->frwd_lock);
mutex_unlock(&session->eh_mutex);
iscsi_destroy_conn(cls_conn);
kfree(tmp_persistent_address);
kfree(tmp_local_ipaddr);
iscsi_put_conn(cls_conn);
}
EXPORT_SYMBOL_GPL(iscsi_conn_teardown);

27
drivers/scsi/scsi_transport_iscsi.c
View File

@ -2137,7 +2137,11 @@ static int iscsi_iter_destroy_conn_fn(struct device *dev, void *data)
{
if (!iscsi_is_conn_dev(dev))
return 0;
return iscsi_destroy_conn(iscsi_dev_to_conn(dev));
iscsi_remove_conn(iscsi_dev_to_conn(dev));
iscsi_put_conn(iscsi_dev_to_conn(dev));
return 0;
}
void iscsi_remove_session(struct iscsi_cls_session *session)
@ -2414,27 +2418,6 @@ void iscsi_remove_conn(struct iscsi_cls_conn *conn)
}
EXPORT_SYMBOL_GPL(iscsi_remove_conn);
/**
* iscsi_destroy_conn - destroy iscsi class connection
* @conn: iscsi cls session
*
* This can be called from a LLD or iscsi_transport.
*/
int iscsi_destroy_conn(struct iscsi_cls_conn *conn)
{
unsigned long flags;
spin_lock_irqsave(&connlock, flags);
list_del(&conn->conn_list);
spin_unlock_irqrestore(&connlock, flags);
transport_unregister_device(&conn->dev);
ISCSI_DBG_TRANS_CONN(conn, "Completing conn destruction\n");
device_unregister(&conn->dev);
return 0;
}
EXPORT_SYMBOL_GPL(iscsi_destroy_conn);
void iscsi_put_conn(struct iscsi_cls_conn *conn)
{
put_device(&conn->dev);

1
include/scsi/scsi_transport_iscsi.h
View File

@ -448,7 +448,6 @@ extern int iscsi_add_conn(struct iscsi_cls_conn *conn);
extern void iscsi_remove_conn(struct iscsi_cls_conn *conn);
extern void iscsi_put_conn(struct iscsi_cls_conn *conn);
extern void iscsi_get_conn(struct iscsi_cls_conn *conn);
extern int iscsi_destroy_conn(struct iscsi_cls_conn *conn);
extern void iscsi_unblock_session(struct iscsi_cls_session *session);
extern void iscsi_block_session(struct iscsi_cls_session *session);
extern struct iscsi_endpoint *iscsi_create_endpoint(int dd_size);