sctp: hold the chunks only after the chunk is enqueued in outq

When a msg is sent, sctp will hold the chunks of this msg and then try
to enqueue them. But if the chunks are not enqueued in sctp_outq_tail()
because of the invalid state, sctp_cmd_interpreter() may still return
success to sctp_sendmsg() after calling sctp_outq_flush(), these chunks
will become orphans and will leak.

So we fix them by moving sctp_chunk_hold() to sctp_outq_tail(), where we
are sure that the chunk is going to get queued.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 1 insertions, 2 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 7e8f0a117106..0b3d8189f140 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -324,6 +324,7 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
                                  sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
                                  "illegal chunk");
 
+                        sctp_chunk_hold(chunk);
                         sctp_outq_tail_data(q, chunk);
                         if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
                                 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 1a32ecdb8bae..bd57300c8e91 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1952,8 +1952,6 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 
         /* Now send the (possibly) fragmented message. */
         list_for_each_entry(chunk, &datamsg->chunks, frag_list) {
-                sctp_chunk_hold(chunk);
-
                 /* Do accounting for the write space.  */
                 sctp_set_owner_w(chunk);