From cfe4bd7a257f6d6f81d3458d8c9d9ec4957539e6 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Mon, 4 Feb 2019 03:27:58 +0800 Subject: [PATCH] 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: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations") Reported-by: Ying Xu Reported-by: syzbot+e33a3a138267ca119c7d@syzkaller.appspotmail.com Signed-off-by: Xin Long Acked-by: Neil Horman Signed-off-by: David S. Miller --- net/sctp/stream.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/net/sctp/stream.c b/net/sctp/stream.c index 80e0ae5534ec..f24633114dfd 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -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); } -- 2.30.2