Set klist lock for sockets to make socket event filters MP-safe

The filterops instances already provide f_modify and f_process
callbacks with proper internal locking. Locking of socket klists
has been the missing detail for MP-safety.

OK mpi@

2 files changed, 50 insertions, 14 deletions

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index afab85de1ee..f0d7046c40c 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket.c,v 1.266 2021/10/22 15:11:32 mpi Exp $	*/
+/*	$OpenBSD: uipc_socket.c,v 1.267 2021/10/24 07:02:47 visa Exp $	*/
 /*	$NetBSD: uipc_socket.c,v 1.21 1996/02/04 02:17:52 christos Exp $	*/
 
 /*
@@ -88,7 +88,7 @@ int	filt_solistenprocess(struct knote *kn, struct kevent *kev);
 int	filt_solisten_common(struct knote *kn, struct socket *so);
 
 const struct filterops solisten_filtops = {
-	.f_flags	= FILTEROP_ISFD,
+	.f_flags	= FILTEROP_ISFD | FILTEROP_MPSAFE,
 	.f_attach	= NULL,
 	.f_detach	= filt_sordetach,
 	.f_event	= filt_solisten,
@@ -97,7 +97,7 @@ const struct filterops solisten_filtops = {
 };
 
 const struct filterops soread_filtops = {
-	.f_flags	= FILTEROP_ISFD,
+	.f_flags	= FILTEROP_ISFD | FILTEROP_MPSAFE,
 	.f_attach	= NULL,
 	.f_detach	= filt_sordetach,
 	.f_event	= filt_soread,
@@ -106,7 +106,7 @@ const struct filterops soread_filtops = {
 };
 
 const struct filterops sowrite_filtops = {
-	.f_flags	= FILTEROP_ISFD,
+	.f_flags	= FILTEROP_ISFD | FILTEROP_MPSAFE,
 	.f_attach	= NULL,
 	.f_detach	= filt_sowdetach,
 	.f_event	= filt_sowrite,
@@ -115,7 +115,7 @@ const struct filterops sowrite_filtops = {
 };
 
 const struct filterops soexcept_filtops = {
-	.f_flags	= FILTEROP_ISFD,
+	.f_flags	= FILTEROP_ISFD | FILTEROP_MPSAFE,
 	.f_attach	= NULL,
 	.f_detach	= filt_sordetach,
 	.f_event	= filt_soexcept,
@@ -173,6 +173,8 @@ socreate(int dom, struct socket **aso, int type, int proto)
 		return (EPROTOTYPE);
 	so = pool_get(&socket_pool, PR_WAITOK | PR_ZERO);
 	rw_init(&so->so_lock, "solock");
+	klist_init(&so->so_rcv.sb_sel.si_note, &socket_klistops, so);
+	klist_init(&so->so_snd.sb_sel.si_note, &socket_klistops, so);
 	sigio_init(&so->so_sigio);
 	TAILQ_INIT(&so->so_q0);
 	TAILQ_INIT(&so->so_q);
@@ -262,6 +264,8 @@ sofree(struct socket *so, int s)
 		}
 	}
 	sigio_free(&so->so_sigio);
+	klist_free(&so->so_rcv.sb_sel.si_note);
+	klist_free(&so->so_snd.sb_sel.si_note);
 #ifdef SOCKET_SPLICE
 	if (so->so_sp) {
 		if (issplicedback(so)) {
@@ -2042,9 +2046,9 @@ soo_kqfilter(struct file *fp, struct knote *kn)
 {
 	struct socket *so = kn->kn_fp->f_data;
 	struct sockbuf *sb;
+	int s;
 
-	KERNEL_ASSERT_LOCKED();
-
+	s = solock(so);
 	switch (kn->kn_filter) {
 	case EVFILT_READ:
 		if (so->so_options & SO_ACCEPTCONN)
@@ -2062,10 +2066,12 @@ soo_kqfilter(struct file *fp, struct knote *kn)
 		sb = &so->so_rcv;
 		break;
 	default:
+		sounlock(so, s);
 		return (EINVAL);
 	}
 
 	klist_insert_locked(&sb->sb_sel.si_note, kn);
+	sounlock(so, s);
 
 	return (0);
 }
@@ -2075,9 +2081,7 @@ filt_sordetach(struct knote *kn)
 {
 	struct socket *so = kn->kn_fp->f_data;
 
-	KERNEL_ASSERT_LOCKED();
-
-	klist_remove_locked(&so->so_rcv.sb_sel.si_note, kn);
+	klist_remove(&so->so_rcv.sb_sel.si_note, kn);
 }
 
 int
@@ -2157,9 +2161,7 @@ filt_sowdetach(struct knote *kn)
 {
 	struct socket *so = kn->kn_fp->f_data;
 
-	KERNEL_ASSERT_LOCKED();
-
-	klist_remove_locked(&so->so_snd.sb_sel.si_note, kn);
+	klist_remove(&so->so_snd.sb_sel.si_note, kn);
 }
 
 int
@@ -2353,6 +2355,36 @@ filt_solistenprocess(struct knote *kn, struct kevent *kev)
 	return (rv);
 }
 
+void
+klist_soassertlk(void *arg)
+{
+	struct socket *so = arg;
+
+	soassertlocked(so);
+}
+
+int
+klist_solock(void *arg)
+{
+	struct socket *so = arg;
+
+	return (solock(so));
+}
+
+void
+klist_sounlock(void *arg, int ls)
+{
+	struct socket *so = arg;
+
+	sounlock(so, ls);
+}
+
+const struct klistops socket_klistops = {
+	.klo_assertlk	= klist_soassertlk,
+	.klo_lock	= klist_solock,
+	.klo_unlock	= klist_sounlock,
+};
+
 #ifdef DDB
 void
 sobuf_print(struct sockbuf *,
diff --git a/sys/kern/uipc_socket2.c b/sys/kern/uipc_socket2.c
index e387e4705f7..59229ef936d 100644
--- a/sys/kern/uipc_socket2.c
+++ b/sys/kern/uipc_socket2.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uipc_socket2.c,v 1.113 2021/07/26 05:51:13 mpi Exp $	*/
+/*	$OpenBSD: uipc_socket2.c,v 1.114 2021/10/24 07:02:47 visa Exp $	*/
 /*	$NetBSD: uipc_socket2.c,v 1.11 1996/02/04 02:17:55 christos Exp $	*/
 
 /*
@@ -189,6 +189,8 @@ sonewconn(struct socket *head, int connstatus)
 	so->so_rcv.sb_lowat = head->so_rcv.sb_lowat;
 	so->so_rcv.sb_timeo_nsecs = head->so_rcv.sb_timeo_nsecs;
 
+	klist_init(&so->so_rcv.sb_sel.si_note, &socket_klistops, so);
+	klist_init(&so->so_snd.sb_sel.si_note, &socket_klistops, so);
 	sigio_init(&so->so_sigio);
 	sigio_copy(&so->so_sigio, &head->so_sigio);
 
@@ -196,6 +198,8 @@ sonewconn(struct socket *head, int connstatus)
 	if ((*so->so_proto->pr_attach)(so, 0)) {
 		(void) soqremque(so, soqueue);
 		sigio_free(&so->so_sigio);
+		klist_free(&so->so_rcv.sb_sel.si_note);
+		klist_free(&so->so_snd.sb_sel.si_note);
 		pool_put(&socket_pool, so);
 		return (NULL);
 	}