git: eeba22217217 - main - sctp: don't keep a pointer to a freed stcb around

From: Michael Tuexen <tuexen_at_FreeBSD.org>
Date: Fri, 15 Apr 2022 13:17:33 UTC
The branch main has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=eeba222172170c380450004fdceac80c3612b1e8

commit eeba222172170c380450004fdceac80c3612b1e8
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2022-04-15 12:00:00 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2022-04-15 12:00:00 +0000

    sctp: don't keep a pointer to a freed stcb around
    
    Reported by:    syzbot+b9ef06efdae7cb9ee414@syzkaller.appspotmail.com
    Reported by:    syzbot+b1e4793e0e6b25b0d510@syzkaller.appspotmail.com
    MFC after:      3 days
---
 sys/netinet/sctp_pcb.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/sys/netinet/sctp_pcb.c b/sys/netinet/sctp_pcb.c
index 4853729dca84..7b340910c2a8 100644
--- a/sys/netinet/sctp_pcb.c
+++ b/sys/netinet/sctp_pcb.c
@@ -3371,8 +3371,10 @@ sctp_inpcb_free(struct sctp_inpcb *inp, int immediate, int from)
 		cnt_in_sd = 0;
 		LIST_FOREACH_SAFE(stcb, &inp->sctp_asoc_list, sctp_tcblist, nstcb) {
 			SCTP_TCB_LOCK(stcb);
+			/* Disconnect the socket please. */
+			stcb->sctp_socket = NULL;
+			SCTP_ADD_SUBSTATE(stcb, SCTP_STATE_CLOSED_SOCKET);
 			if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
-				stcb->sctp_socket = NULL;
 				/* Skip guys being freed */
 				cnt_in_sd++;
 				if (stcb->asoc.state & SCTP_STATE_IN_ACCEPT_QUEUE) {
@@ -3404,9 +3406,6 @@ sctp_inpcb_free(struct sctp_inpcb *inp, int immediate, int from)
 				}
 				continue;
 			}
-			/* Disconnect the socket please */
-			stcb->sctp_socket = NULL;
-			SCTP_ADD_SUBSTATE(stcb, SCTP_STATE_CLOSED_SOCKET);
 			if ((stcb->asoc.size_on_reasm_queue > 0) ||
 			    (stcb->asoc.control_pdapi) ||
 			    (stcb->asoc.size_on_all_streams > 0) ||