From: Wyatt Feng <bronzed_45_vested@icloud.com> stable inclusion from stable-v5.10.259 commit 0cd2dc6dce8ca47212cd306ccd52eb315ef3cf85 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15635 CVE: CVE-2026-52929 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit a5f8a90ac9f77c678a9781c0a464b635e0d63e49 upstream. When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and then lowers outcnt. That leaves removed stream metadata behind, so a later re-add can reuse a stale ext and hit a null-pointer dereference in the scheduler get path. Fix the rollback by tearing down the removed stream state the same way other stream resizes do. Unschedule the current scheduler state, drop the removed stream ext state with sctp_stream_outq_migrate(), and then reschedule the remaining streams. This keeps scheduler-private RR/FC/PRIO lists consistent while fully rolling back denied outgoing stream additions. Fixes: 637784ade221 ("sctp: introduce priority based stream scheduler") Cc: stable@kernel.org Reported-by: Yuan Tan <yuantan098@gmail.com> Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Reported-by: Zhengchuan Liang <zcliangcn@gmail.com> Reported-by: Xin Liu <bird@lzu.edu.cn> Signed-off-by: Wyatt Feng <bronzed_45_vested@icloud.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/d78954ecd94954653ee299400e98d74a03a6f7d3.1780603399... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lin Yujun <linyujun809@h-partners.com> Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> --- net/sctp/stream.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/sctp/stream.c b/net/sctp/stream.c index 73c212ae69d8..6697ee605536 100644 --- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -1040,21 +1040,25 @@ struct sctp_chunk *sctp_process_strreset_resp( *evp = sctp_ulpevent_make_assoc_reset_event(asoc, flags, stsn, rtsn, GFP_ATOMIC); } else if (req->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) { struct sctp_strreset_addstrm *addstrm; + const struct sctp_sched_ops *sched; __u16 number; addstrm = (struct sctp_strreset_addstrm *)req; nums = ntohs(addstrm->number_of_streams); number = stream->outcnt - nums; if (result == SCTP_STRRESET_PERFORMED) { for (i = number; i < stream->outcnt; i++) SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN; } else { - sctp_stream_shrink_out(stream, number); + sched = sctp_sched_ops_from_stream(stream); + sched->unsched_all(stream); + sctp_stream_outq_migrate(stream, NULL, number); + sched->sched_all(stream); stream->outcnt = number; } *evp = sctp_ulpevent_make_stream_change_event(asoc, flags, 0, nums, GFP_ATOMIC); -- 2.43.0