Patch "sctp: only allow the asoc reset when the asoc outq is empty" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    sctp: only allow the asoc reset when the asoc outq is empty

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sctp-only-allow-the-asoc-reset-when-the-asoc-outq-is-empty.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Feb  1 13:45:42 CET 2018
From: Xin Long <lucien.xin@gmail.com>
Date: Sat, 25 Nov 2017 21:05:34 +0800
Subject: sctp: only allow the asoc reset when the asoc outq is empty

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


[ Upstream commit 5c6144a0eb5366ae07fc5059301b139338f39bbd ]

As it says in rfc6525#section5.1.4, before sending the request,

   C2:  The sender has either no outstanding TSNs or considers all
        outstanding TSNs abandoned.

Prior to this patch, it tried to consider all outstanding TSNs abandoned
by dropping all chunks in all outqs with sctp_outq_free (even including
sacked, retransmit and transmitted queues) when doing this reset, which
is too aggressive.

To make it work gently, this patch will only allow the asoc reset when
the sender has no outstanding TSNs by checking if unsent, transmitted
and retransmit are all empty with sctp_outq_is_empty before sending
and processing the request.

Fixes: 692787cef651 ("sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/stream.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -224,6 +224,9 @@ int sctp_send_reset_assoc(struct sctp_as
 	if (asoc->strreset_outstanding)
 		return -EINPROGRESS;
 
+	if (!sctp_outq_is_empty(&asoc->outqueue))
+		return -EAGAIN;
+
 	chunk = sctp_make_strreset_tsnreq(asoc);
 	if (!chunk)
 		return -ENOMEM;
@@ -544,6 +547,12 @@ struct sctp_chunk *sctp_process_strreset
 		}
 		goto err;
 	}
+
+	if (!sctp_outq_is_empty(&asoc->outqueue)) {
+		result = SCTP_STRRESET_IN_PROGRESS;
+		goto err;
+	}
+
 	asoc->strreset_inseq++;
 
 	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))


Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.14/sctp-set-sender-next_tsn-for-the-old-result-with-ctsn_ack_point-plus-1.patch
queue-4.14/sctp-only-allow-the-asoc-reset-when-the-asoc-outq-is-empty.patch
queue-4.14/sctp-avoid-flushing-unsent-queue-when-doing-asoc-reset.patch