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authorYing Xue <ying.xue@windriver.com>2014-04-21 10:55:52 +0800
committerDavid S. Miller <davem@davemloft.net>2014-04-22 21:17:53 -0400
commita8b9b96e959f3c035af20b1bd2ba67b0b7269b19 (patch)
tree02d52832745176ee6d63579f50d375caddd1fc62 /net/tipc/discover.c
parent28dd94187afd660a350d01d6bad4a915a6d570b8 (diff)
downloadlinux-a8b9b96e959f3c035af20b1bd2ba67b0b7269b19.tar.bz2
tipc: fix race in disc create/delete
Commit a21a584d6720ce349b05795b9bcfab3de8e58419 (tipc: fix neighbor detection problem after hw address change) introduces a race condition involving tipc_disc_delete() and tipc_disc_add/remove_dest that can cause TIPC to dereference the pointer to the bearer discovery request structure after it has been freed since a stray pointer is left in the bearer structure. In order to fix the issue, the process of resetting the discovery request handler is optimized: the discovery request handler and request buffer are just reset instead of being freed, allocated and initialized. As the request point is always valid and the request's lock is taken while the request handler is reset, the race doesn't happen any more. Reported-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/discover.c')
-rw-r--r--net/tipc/discover.c53
1 files changed, 35 insertions, 18 deletions
diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index 3a8f211f08c7..ada42e436f5e 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -71,22 +71,19 @@ struct tipc_link_req {
* @type: message type (request or response)
* @b_ptr: ptr to bearer issuing message
*/
-static struct sk_buff *tipc_disc_init_msg(u32 type, struct tipc_bearer *b_ptr)
+static void tipc_disc_init_msg(struct sk_buff *buf, u32 type,
+ struct tipc_bearer *b_ptr)
{
- struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE);
struct tipc_msg *msg;
u32 dest_domain = b_ptr->domain;
- if (buf) {
- msg = buf_msg(buf);
- tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
- msg_set_non_seq(msg, 1);
- msg_set_node_sig(msg, tipc_random);
- msg_set_dest_domain(msg, dest_domain);
- msg_set_bc_netid(msg, tipc_net_id);
- b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
- }
- return buf;
+ msg = buf_msg(buf);
+ tipc_msg_init(msg, LINK_CONFIG, type, INT_H_SIZE, dest_domain);
+ msg_set_non_seq(msg, 1);
+ msg_set_node_sig(msg, tipc_random);
+ msg_set_dest_domain(msg, dest_domain);
+ msg_set_bc_netid(msg, tipc_net_id);
+ b_ptr->media->addr2msg(&b_ptr->addr, msg_media_addr(msg));
}
/**
@@ -241,8 +238,9 @@ void tipc_disc_rcv(struct sk_buff *buf, struct tipc_bearer *b_ptr)
link_fully_up = link_working_working(link);
if ((type == DSC_REQ_MSG) && !link_fully_up) {
- rbuf = tipc_disc_init_msg(DSC_RESP_MSG, b_ptr);
+ rbuf = tipc_buf_acquire(INT_H_SIZE);
if (rbuf) {
+ tipc_disc_init_msg(rbuf, DSC_RESP_MSG, b_ptr);
tipc_bearer_send(b_ptr->identity, rbuf, &media_addr);
kfree_skb(rbuf);
}
@@ -349,12 +347,11 @@ int tipc_disc_create(struct tipc_bearer *b_ptr, struct tipc_media_addr *dest)
if (!req)
return -ENOMEM;
- req->buf = tipc_disc_init_msg(DSC_REQ_MSG, b_ptr);
- if (!req->buf) {
- kfree(req);
- return -ENOMSG;
- }
+ req->buf = tipc_buf_acquire(INT_H_SIZE);
+ if (!req->buf)
+ return -ENOMEM;
+ tipc_disc_init_msg(req->buf, DSC_REQ_MSG, b_ptr);
memcpy(&req->dest, dest, sizeof(*dest));
req->bearer_id = b_ptr->identity;
req->domain = b_ptr->domain;
@@ -379,3 +376,23 @@ void tipc_disc_delete(struct tipc_link_req *req)
kfree_skb(req->buf);
kfree(req);
}
+
+/**
+ * tipc_disc_reset - reset object to send periodic link setup requests
+ * @b_ptr: ptr to bearer issuing requests
+ * @dest_domain: network domain to which links can be established
+ */
+void tipc_disc_reset(struct tipc_bearer *b_ptr)
+{
+ struct tipc_link_req *req = b_ptr->link_req;
+
+ spin_lock_bh(&req->lock);
+ tipc_disc_init_msg(req->buf, DSC_REQ_MSG, b_ptr);
+ req->bearer_id = b_ptr->identity;
+ req->domain = b_ptr->domain;
+ req->num_nodes = 0;
+ req->timer_intv = TIPC_LINK_REQ_INIT;
+ k_start_timer(&req->timer, req->timer_intv);
+ tipc_bearer_send(req->bearer_id, req->buf, &req->dest);
+ spin_unlock_bh(&req->lock);
+}