[PATCH 4.14 14/21] sctp: not increase streams incnt before sending addstrm_in request

Greg Kroah-Hartman
2018-11-22T05:44:35Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit e1e46479847e66f78f79d8c24d5169a5954b3fc2 ]

Different from processing the addstrm_out request, The receiver handles
an addstrm_in request by sending back an addstrm_out request to the
sender who will increase its stream's in and incnt later.

Now stream->incnt has been increased since it sent out the addstrm_in
request in sctp_send_add_streams(), with the wrong stream->incnt will
even cause crash when copying stream info from the old stream's in to
the new one's in sctp_process_strreset_addstrm_out().

This patch is to fix it by simply removing the stream->incnt change
from sctp_send_add_streams().

Fixes: 242bd2d519d7 ("sctp: implement sender-side procedures for Add Incoming/Outgoing Streams Request Parameter")
Reported-by: Jianwen Ji <jiji@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sctp/stream.c | 1 -
1 file changed, 1 deletion(-)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -310,7 +310,6 @@ int sctp_send_add_streams(struct sctp_as
goto out;
}

- stream->incnt = incnt;
stream->outcnt = outcnt;

asoc->strreset_outstanding = !!out + !!in;