[SCTP]: Set assoc_id correctly during INIT collision.

During the INIT/COOKIE-ACK collision cases, it's possible to get
into a situation where the association id is not yet set at the time
of the user event generation.  As a result, user events have an
association id set to 0 which will confuse applications.

This happens if we hit case B of duplicate cookie processing.
In the particular example found and provided by Oscar Isaula
<Oscar.Isaula@motorola.com>, flow looks like this:
A				B
---- INIT------->  (lost)
	    <---------INIT------
---- INIT-ACK--->
	    <------ Cookie ECHO

When the Cookie Echo is received, we end up trying to update the
association that was created on A as a result of the (lost) INIT,
but that association doesn't have the ID set yet.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 13 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index be783a3761c4..8d18f570c2e6 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1939,7 +1939,6 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
          * association.
          */
         if (!asoc->temp) {
-                int assoc_id;
                 int error;
 
                 asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
@@ -1947,19 +1946,9 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
                 if (!asoc->ssnmap)
                         goto clean_up;
 
-        retry:
-                if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
+                error = sctp_assoc_set_id(asoc, gfp);
+                if (error)
                         goto clean_up;
-                spin_lock_bh(&sctp_assocs_id_lock);
-                error = idr_get_new_above(&sctp_assocs_id, (void *)asoc, 1,
-                                          &assoc_id);
-                spin_unlock_bh(&sctp_assocs_id_lock);
-                if (error == -EAGAIN)
-                        goto retry;
-                else if (error)
-                        goto clean_up;
-
-                asoc->assoc_id = (sctp_assoc_t) assoc_id;
         }
 
         /* ADDIP Section 4.1 ASCONF Chunk Procedures