[PATCH AUTOSEL 4.19 034/258] sctp: Fix SKB list traversal in sctp_intl_store_reasm().
From: Sasha Levin <sashal@kernel.org>
Date: 2019-01-28 16:01:03
Also in:
linux-sctp, lkml, stable
Subsystem:
networking [general], sctp protocol, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Marcelo Ricardo Leitner, Xin Long, Linus Torvalds
From: "David S. Miller" <davem@davemloft.net> [ Upstream commit 348bbc25c40844c5efa083a3842c7f53d70a815e ] To be fully correct, an iterator has an undefined value when something like skb_queue_walk() naturally terminates. This will actually matter when SKB queues are converted over to list_head. Formalize what this code ends up doing with the current implementation. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/sctp/stream_interleave.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c
index 500449b72eca..2b499a85db0e 100644
--- a/net/sctp/stream_interleave.c
+++ b/net/sctp/stream_interleave.c@@ -140,7 +140,7 @@ static void sctp_intl_store_reasm(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event) { struct sctp_ulpevent *cevent; - struct sk_buff *pos; + struct sk_buff *pos, *loc; pos = skb_peek_tail(&ulpq->reasm); if (!pos) {
@@ -166,23 +166,30 @@ static void sctp_intl_store_reasm(struct sctp_ulpq *ulpq, return; } + loc = NULL; skb_queue_walk(&ulpq->reasm, pos) { cevent = sctp_skb2event(pos); if (event->stream < cevent->stream || (event->stream == cevent->stream && - MID_lt(event->mid, cevent->mid))) + MID_lt(event->mid, cevent->mid))) { + loc = pos; break; - + } if (event->stream == cevent->stream && event->mid == cevent->mid && !(cevent->msg_flags & SCTP_DATA_FIRST_FRAG) && (event->msg_flags & SCTP_DATA_FIRST_FRAG || - event->fsn < cevent->fsn)) + event->fsn < cevent->fsn)) { + loc = pos; break; + } } - __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event)); + if (!loc) + __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event)); + else + __skb_queue_before(&ulpq->reasm, loc, sctp_event2skb(event)); } static struct sctp_ulpevent *sctp_intl_retrieve_partial(
--
2.19.1