Commit cfe4bd7a authored Feb 04, 2019 by Xin Long Committed by David S. Miller Feb 03, 2019

sctp: check and update stream->out_curr when allocating stream_out



Now when using stream reconfig to add out streams, stream->out
will get re-allocated, and all old streams' information will
be copied to the new ones and the old ones will be freed.

So without stream->out_curr updated, next time when trying to
send from stream->out_curr stream, a panic would be caused.

This patch is to check and update stream->out_curr when
allocating stream_out.

v1->v2:
  - define fa_index() to get elem index from stream->out_curr.
v2->v3:
  - repost with no change.

Fixes: 5bbbbe32 ("sctp: introduce stream scheduler foundations")
Reported-by: Ying Xu <yinxu@redhat.com>
Reported-by:  <syzbot+e33a3a138267ca119c7d@syzkaller.appspotmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 8dfb8d2c

net/sctp/stream.c

+20 −0

Original line number	Diff line number	Diff line
		@@ -84,6 +84,19 @@ static void fa_zero(struct flex_array *fa, size_t index, size_t count)
		}
		}

		static size_t fa_index(struct flex_array fa, void elem, size_t count)
		{
		size_t index = 0;

		while (count--) {
		if (elem == flex_array_get(fa, index))
		break;
		index++;
		}

		return index;
		}

		/* Migrates chunks from stream queues to new stream queues if needed,
		* but not across associations. Also, removes those chunks to streams
		* higher than the new max.
		@@ -147,6 +160,13 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,

		if (stream->out) {
		fa_copy(out, stream->out, 0, min(outcnt, stream->outcnt));
		if (stream->out_curr) {
		size_t index = fa_index(stream->out, stream->out_curr,
		stream->outcnt);

		BUG_ON(index == stream->outcnt);
		stream->out_curr = flex_array_get(out, index);
		}
		fa_free(stream->out);
		}

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