[PATCH 4.16 45/55] sctp: clear the new asocs stream outcnt in sctp_stream_update

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xin Long <lucien.xin@xxxxxxxxx>

[ Upstream commit 6a9a27d5397fc6c52f90c09ddab91e65053584aa ]

When processing a duplicate cookie-echo chunk, sctp moves the new
temp asoc's stream out/in into the old asoc, and later frees this
new temp asoc.

But now after this move, the new temp asoc's stream->outcnt is not
cleared while stream->out is set to NULL, which would cause a same
crash as the one fixed in Commit 79d0895140e9 ("sctp: fix error
path in sctp_stream_init") when freeing this asoc later.

This fix is to clear this outcnt in sctp_stream_update.

Fixes: f952be79cebd ("sctp: introduce struct sctp_stream_out_ext")
Reported-by: Jianwen Ji <jiji@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/sctp/stream.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -240,6 +240,8 @@ void sctp_stream_update(struct sctp_stre
 
 	new->out = NULL;
 	new->in  = NULL;
+	new->outcnt = 0;
+	new->incnt  = 0;
 }
 
 static int sctp_send_reconf(struct sctp_association *asoc,