From b02b69c8a403859ec72090742727e853d606a325 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Tue, 17 Aug 2010 11:00:07 +0000 Subject: [PATCH] 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 Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller --- net/tipc/link.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/net/tipc/link.c b/net/tipc/link.c index a3616b99529b..9d18c9b7638b 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -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))) -- 2.30.2