git: e99c76951e10 - stable/14 - if_pfsync: lock buckets during pfsync_drop()

The branch stable/14 has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=e99c76951e1092464037cd4bcbce1e05a3589acc

commit e99c76951e1092464037cd4bcbce1e05a3589acc
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2024-07-07 14:42:48 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2024-07-17 15:23:48 +0000

    if_pfsync: lock buckets during pfsync_drop()
    
    We failed to lock buckets while dropping messages, which could potentially lead
    to crashes, and is the likely cause of panics like:
    
    > pfsync_drop: st->sync_state == q
    > # pfsync_drop
    > # pfsync_q_ins
    > # pfsync_insert_state
    > # pf_state_insert
    > ...
    
    Handle this by only handling the currently relevant (and this locked) bucket.
    This ensures that the bucket is locked while we manipulate it.
    While here also log slightly more information in the KASSERT().
    
    MFC after:      2 weeks
    Sponsored by:   Orange Business Services
    
    (cherry picked from commit 5f75cd390a67cbec06993c4c66f784f0f777c854)
---
 sys/netpfil/pf/if_pfsync.c | 70 ++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 27 deletions(-)

diff --git a/sys/netpfil/pf/if_pfsync.c b/sys/netpfil/pf/if_pfsync.c
index 9aad44ccaf99..7af9ce8f468d 100644
--- a/sys/netpfil/pf/if_pfsync.c
+++ b/sys/netpfil/pf/if_pfsync.c
@@ -345,7 +345,8 @@ static void	pfsync_defer_tmo(void *);
 static void	pfsync_request_update(u_int32_t, u_int64_t);
 static bool	pfsync_update_state_req(struct pf_kstate *);
 
-static void	pfsync_drop(struct pfsync_softc *);
+static void	pfsync_drop_all(struct pfsync_softc *);
+static void	pfsync_drop(struct pfsync_softc *, int);
 static void	pfsync_sendout(int, int);
 static void	pfsync_send_plus(void *, size_t);
 
@@ -485,7 +486,7 @@ pfsync_clone_destroy(struct ifnet *ifp)
 	bpfdetach(ifp);
 	if_detach(ifp);
 
-	pfsync_drop(sc);
+	pfsync_drop_all(sc);
 
 	if_free(ifp);
 	pfsync_multicast_cleanup(sc);
@@ -1736,40 +1737,54 @@ pfsync_out_del_c(struct pf_kstate *st, void *buf)
 }
 
 static void
-pfsync_drop(struct pfsync_softc *sc)
+pfsync_drop_all(struct pfsync_softc *sc)
 {
-	struct pf_kstate *st, *next;
-	struct pfsync_upd_req_item *ur;
 	struct pfsync_bucket *b;
 	int c;
-	enum pfsync_q_id q;
 
 	for (c = 0; c < pfsync_buckets; c++) {
 		b = &sc->sc_buckets[c];
-		for (q = 0; q < PFSYNC_Q_COUNT; q++) {
-			if (TAILQ_EMPTY(&b->b_qs[q]))
-				continue;
 
-			TAILQ_FOREACH_SAFE(st, &b->b_qs[q], sync_list, next) {
-				KASSERT(st->sync_state == pfsync_qid_sstate[q],
-					("%s: st->sync_state == q",
-						__func__));
-				st->sync_state = PFSYNC_S_NONE;
-				pf_release_state(st);
-			}
-			TAILQ_INIT(&b->b_qs[q]);
-		}
+		PFSYNC_BUCKET_LOCK(b);
+		pfsync_drop(sc, c);
+		PFSYNC_BUCKET_UNLOCK(b);
+	}
+}
 
-		while ((ur = TAILQ_FIRST(&b->b_upd_req_list)) != NULL) {
-			TAILQ_REMOVE(&b->b_upd_req_list, ur, ur_entry);
-			free(ur, M_PFSYNC);
+static void
+pfsync_drop(struct pfsync_softc *sc, int c)
+{
+	struct pf_kstate *st, *next;
+	struct pfsync_upd_req_item *ur;
+	struct pfsync_bucket *b;
+	enum pfsync_q_id q;
+
+	b = &sc->sc_buckets[c];
+	PFSYNC_BUCKET_LOCK_ASSERT(b);
+
+	for (q = 0; q < PFSYNC_Q_COUNT; q++) {
+		if (TAILQ_EMPTY(&b->b_qs[q]))
+			continue;
+
+		TAILQ_FOREACH_SAFE(st, &b->b_qs[q], sync_list, next) {
+			KASSERT(st->sync_state == pfsync_qid_sstate[q],
+				("%s: st->sync_state %d == q %d",
+					__func__, st->sync_state, q));
+			st->sync_state = PFSYNC_S_NONE;
+			pf_release_state(st);
 		}
+		TAILQ_INIT(&b->b_qs[q]);
+	}
 
-		b->b_len = PFSYNC_MINPKT;
-		free(b->b_plus, M_PFSYNC);
-		b->b_plus = NULL;
-		b->b_pluslen = 0;
+	while ((ur = TAILQ_FIRST(&b->b_upd_req_list)) != NULL) {
+		TAILQ_REMOVE(&b->b_upd_req_list, ur, ur_entry);
+		free(ur, M_PFSYNC);
 	}
+
+	b->b_len = PFSYNC_MINPKT;
+	free(b->b_plus, M_PFSYNC);
+	b->b_plus = NULL;
+	b->b_pluslen = 0;
 }
 
 static void
@@ -1793,7 +1808,7 @@ pfsync_sendout(int schedswi, int c)
 	PFSYNC_BUCKET_LOCK_ASSERT(b);
 
 	if (!bpf_peers_present(ifp->if_bpf) && sc->sc_sync_if == NULL) {
-		pfsync_drop(sc);
+		pfsync_drop(sc, c);
 		return;
 	}
 
@@ -1841,6 +1856,7 @@ pfsync_sendout(int schedswi, int c)
 #endif
 	default:
 		m_freem(m);
+		pfsync_drop(sc, c);
 		return;
 	}
 	m->m_len = m->m_pkthdr.len = len;
@@ -2401,8 +2417,8 @@ pfsync_q_ins(struct pf_kstate *st, int sync_state, bool ref)
 	}
 
 	b->b_len += nlen;
-	TAILQ_INSERT_TAIL(&b->b_qs[q], st, sync_list);
 	st->sync_state = pfsync_qid_sstate[q];
+	TAILQ_INSERT_TAIL(&b->b_qs[q], st, sync_list);
 	if (ref)
 		pf_ref_state(st);
 }