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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Ying Xu <yinxu@redhat.com>,
	Xin Long <lucien.xin@gmail.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 13/17] sctp: shrink stream outq when fails to do addstream reconf
Date: Thu, 30 Jul 2020 10:04:39 +0200
Message-ID: <20200730074421.111265800@linuxfoundation.org> (raw)
In-Reply-To: <20200730074420.449233408@linuxfoundation.org>

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

[ Upstream commit 3ecdda3e9ad837cf9cb41b6faa11b1af3a5abc0c ]

When adding a stream with stream reconf, the new stream firstly is in
CLOSED state but new out chunks can still be enqueued. Then once gets
the confirmation from the peer, the state will change to OPEN.

However, if the peer denies, it needs to roll back the stream. But when
doing that, it only sets the stream outcnt back, and the chunks already
in the new stream don't get purged. It caused these chunks can still be
dequeued in sctp_outq_dequeue_data().

As its stream is still in CLOSE, the chunk will be enqueued to the head
again by sctp_outq_head_data(). This chunk will never be sent out, and
the chunks after it can never be dequeued. The assoc will be 'hung' in
a dead loop of sending this chunk.

To fix it, this patch is to purge these chunks already in the new
stream by calling sctp_stream_shrink_out() when failing to do the
addstream reconf.

Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter")
Reported-by: Ying Xu <yinxu@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 |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -1143,11 +1143,13 @@ struct sctp_chunk *sctp_process_strreset
 		nums = ntohs(addstrm->number_of_streams);
 		number = stream->outcnt - nums;
 
-		if (result == SCTP_STRRESET_PERFORMED)
+		if (result == SCTP_STRRESET_PERFORMED) {
 			for (i = number; i < stream->outcnt; i++)
 				SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
-		else
+		} else {
+			sctp_stream_shrink_out(stream, number);
 			stream->outcnt = number;
+		}
 
 		*evp = sctp_ulpevent_make_stream_change_event(asoc, flags,
 			0, nums, GFP_ATOMIC);



  parent reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30  8:04 [PATCH 4.19 00/17] 4.19.136-rc1 review Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 01/17] AX.25: Fix out-of-bounds read in ax25_connect() Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 02/17] AX.25: Prevent out-of-bounds read in ax25_sendmsg() Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 03/17] dev: Defer free of skbs in flush_backlog Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 04/17] drivers/net/wan/x25_asy: Fix to make it work Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 05/17] ip6_gre: fix null-ptr-deref in ip6gre_init_net() Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 06/17] net-sysfs: add a newline when printing tx_timeout by sysfs Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 07/17] net: udp: Fix wrong clean up for IS_UDPLITE macro Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 08/17] qrtr: orphan socket in qrtr_release() Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 09/17] rxrpc: Fix sendmsg() returning EPIPE due to recvmsg() returning ENODATA Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 10/17] tcp: allow at most one TLP probe per flight Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 11/17] AX.25: Prevent integer overflows in connect and sendmsg Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 12/17] sctp: shrink stream outq only when new outcnt < old outcnt Greg Kroah-Hartman
2020-07-30  8:04 ` Greg Kroah-Hartman [this message]
2020-07-30  8:04 ` [PATCH 4.19 14/17] udp: Copy has_conns in reuseport_grow() Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 15/17] udp: Improve load balancing for SO_REUSEPORT Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 16/17] rtnetlink: Fix memory(net_device) leak when ->newlink fails Greg Kroah-Hartman
2020-07-30  8:04 ` [PATCH 4.19 17/17] regmap: debugfs: check count when read regmap file Greg Kroah-Hartman
2020-07-30 16:47 ` [PATCH 4.19 00/17] 4.19.136-rc1 review Guenter Roeck
2020-07-31 12:00 ` Naresh Kamboju
2020-07-31 12:52 ` Jon Hunter

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