tipc: Fix race condition when creating socket or native port
This patch eliminates the (very remote) chance of a crash resulting
from a partially initialized socket or native port unexpectedly
receiving a message. Now, during the creation of a socket or native
port, the underlying generic port's lock is not released until all
initialization required to handle incoming messages has been done.
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/port.c b/net/tipc/port.c
index 2f58064..757de38 100644
--- a/net/tipc/port.c
+++ b/net/tipc/port.c
@@ -211,15 +211,18 @@
}
/**
- * tipc_createport_raw - create a native TIPC port
+ * tipc_createport_raw - create a generic TIPC port
*
- * Returns local port reference
+ * Returns port reference, or 0 if unable to create it
+ *
+ * Note: The newly created port is returned in the locked state.
*/
u32 tipc_createport_raw(void *usr_handle,
u32 (*dispatcher)(struct tipc_port *, struct sk_buff *),
void (*wakeup)(struct tipc_port *),
- const u32 importance)
+ const u32 importance,
+ struct tipc_port **tp_ptr)
{
struct port *p_ptr;
struct tipc_msg *msg;
@@ -237,7 +240,6 @@
return 0;
}
- tipc_port_lock(ref);
p_ptr->publ.usr_handle = usr_handle;
p_ptr->publ.max_pkt = MAX_PKT_DEFAULT;
p_ptr->publ.ref = ref;
@@ -262,7 +264,7 @@
INIT_LIST_HEAD(&p_ptr->port_list);
list_add_tail(&p_ptr->port_list, &ports);
spin_unlock_bh(&tipc_port_list_lock);
- tipc_port_unlock(p_ptr);
+ *tp_ptr = &p_ptr->publ;
return ref;
}
@@ -1053,6 +1055,7 @@
{
struct user_port *up_ptr;
struct port *p_ptr;
+ struct tipc_port *tp_ptr;
u32 ref;
up_ptr = kmalloc(sizeof(*up_ptr), GFP_ATOMIC);
@@ -1060,12 +1063,13 @@
warn("Port creation failed, no memory\n");
return -ENOMEM;
}
- ref = tipc_createport_raw(NULL, port_dispatcher, port_wakeup, importance);
- p_ptr = tipc_port_lock(ref);
- if (!p_ptr) {
+ ref = tipc_createport_raw(NULL, port_dispatcher, port_wakeup,
+ importance, &tp_ptr);
+ if (ref == 0) {
kfree(up_ptr);
return -ENOMEM;
}
+ p_ptr = (struct port *)tp_ptr;
p_ptr->user_port = up_ptr;
up_ptr->user_ref = user_ref;