From 348bbc25c40844c5efa083a3842c7f53d70a815e Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sat, 10 Nov 2018 19:28:27 -0800 Subject: sctp: Fix SKB list traversal in sctp_intl_store_reasm(). 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 --- net/sctp/stream_interleave.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'net') diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c index 0a78cdf86463..368d9c33fde1 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( -- cgit v1.2.3-59-g8ed1b