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tipc: Check for disabled bearer when processing incoming messages 

Add a check to tipc_recv_msg() to ensure it discards messages
arriving on a newly disabled bearer.  This is needed to deal with a
race condition that can arise if the bearer is in the midst of being
disabled when it receives a message.  Performing the check after
tipc_net_lock has been taken ensures that TIPC's bearers are in a
stable state while the message is being processed.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Allan Stephens 2010-08-17 11:00:07 +00:00 committed by David S. Miller
parent f662c07058
commit b02b69c8a4
1 changed files with 14 additions and 0 deletions
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14
net/tipc/link.c
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@ -1802,6 +1802,15 @@ static int link_recv_buf_validate(struct sk_buff *buf)
return pskb_may_pull(buf, hdr_size);
}
/**
* tipc_recv_msg - process TIPC messages arriving from off-node
* @head: pointer to message buffer chain
* @tb_ptr: pointer to bearer message arrived on
*
* Invoked with no locks held. Bearer pointer must point to a valid bearer
* structure (i.e. cannot be NULL), but bearer can be inactive.
*/
void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
{
read_lock_bh(&tipc_net_lock);
@ -1819,6 +1828,11 @@ void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *tb_ptr)
head = head->next;
/* Ensure bearer is still enabled */
if (unlikely(!b_ptr->active))
goto cont;
/* Ensure message is well-formed */
if (unlikely(!link_recv_buf_validate(buf)))