From d30602a2b4952571ca4dcf302422cd86f4bfaa6a Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Wed, 1 Sep 2021 10:27:51 -0400 Subject: [PATCH] sctp: Hold association locks across socket wakeups when freeing At this point we do not hold the inpcb lock, so the only thing holding the socket reference live is the TCB lock, which needs to be acquired by sctp_inpcb_free() in order to destroy associations. Defer the unlock to until after we dereference the socket reference. Reported by: syzbot+1d0f2c4675de76a4cf1e@syzkaller.appspotmail.com Reported by: syzbot+fabee77954fe69d3a5ad@syzkaller.appspotmail.com Reviewed by: tuexen Sponsored by: The FreeBSD Foundation (cherry picked from commit d35be50f57797a400ff68a37777405029bf9730a) --- sys/netinet/sctp_pcb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/netinet/sctp_pcb.c b/sys/netinet/sctp_pcb.c index 12f2d5d7fb7..fc3cd79c5d8 100644 --- a/sys/netinet/sctp_pcb.c +++ b/sys/netinet/sctp_pcb.c @@ -4785,8 +4785,6 @@ sctp_free_assoc(struct sctp_inpcb *inp, struct sctp_tcb *stcb, int from_inpcbfre SCTP_CLEAR_SUBSTATE(stcb, SCTP_STATE_IN_ACCEPT_QUEUE); sctp_timer_start(SCTP_TIMER_TYPE_ASOCKILL, inp, stcb, NULL); } - SCTP_TCB_SEND_UNLOCK(stcb); - SCTP_TCB_UNLOCK(stcb); if ((inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_ALLGONE) || (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE)) /* nothing around */ @@ -4796,6 +4794,8 @@ sctp_free_assoc(struct sctp_inpcb *inp, struct sctp_tcb *stcb, int from_inpcbfre sctp_sorwakeup(inp, so); sctp_sowwakeup(inp, so); } + SCTP_TCB_SEND_UNLOCK(stcb); + SCTP_TCB_UNLOCK(stcb); #ifdef SCTP_LOG_CLOSING sctp_log_closing(inp, stcb, 9);