Subject: [PATCH 17/38] sctp: remove sched init from sctp_stream_init

From: Xin Long <[email-masked]>
Date: Fri, 8 Mar 2019 15:49:16 +0800

[ Upstream commit 2e990dfd13974d9eae493006f42ffb48707970ef ]

syzbot reported a NULL-ptr deref caused by that sched->init() in
sctp_stream_init() set stream->rr_next = NULL.

  kasan: GPF could be caused by NULL-ptr deref or user memory access
  RIP: 0010:sctp_sched_rr_dequeue+0xd3/0x170 net/sctp/stream_sched_rr.c:141
  Call Trace:
    sctp_outq_dequeue_data net/sctp/outqueue.c:90 [inline]
    sctp_outq_flush_data net/sctp/outqueue.c:1079 [inline]
    sctp_outq_flush+0xba2/0x2790 net/sctp/outqueue.c:1205

All sched info is saved in sout->ext now, in sctp_stream_init()
sctp_stream_alloc_out() will not change it, there's no need to
call sched->init() again, since sctp_outq_init() has already
done it.

Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: [email-masked]
Signed-off-by: Xin Long <[email-masked]>
Acked-by: Neil Horman <[email-masked]>
Acked-by: Marcelo Ricardo Leitner <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/sctp/stream.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 2936ed17bf9e..3b47457862cc 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -230,8 +230,6 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
 	for (i = 0; i < stream->outcnt; i++)
 		SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
 
-	sched->init(stream);
-
 in:
 	sctp_stream_interleave_init(stream);
 	if (!incnt)
-- 
2.20.1