diff --git a/sys/kern/sys_socket.c b/sys/kern/sys_socket.c
--- a/sys/kern/sys_socket.c
+++ b/sys/kern/sys_socket.c
@@ -90,6 +90,7 @@
 extern fo_kqfilter_t soo_kqfilter;
 static fo_stat_t soo_stat;
 static fo_close_t soo_close;
+static fo_chmod_t soo_chmod;
 static fo_fill_kinfo_t soo_fill_kinfo;
 static fo_aio_queue_t soo_aio_queue;
 
@@ -104,7 +105,7 @@
 	.fo_kqfilter = soo_kqfilter,
 	.fo_stat = soo_stat,
 	.fo_close = soo_close,
-	.fo_chmod = invfo_chmod,
+	.fo_chmod = soo_chmod,
 	.fo_chown = invfo_chown,
 	.fo_sendfile = invfo_sendfile,
 	.fo_fill_kinfo = soo_fill_kinfo,
@@ -353,6 +354,20 @@
 	return (error);
 }
 
+static int
+soo_chmod(struct file *fp, mode_t mode, struct ucred *cred, struct thread *td)
+{
+	struct socket *so;
+	int error;
+
+	so = fp->f_data;
+	if (so->so_proto->pr_chmod != NULL)
+		error = so->so_proto->pr_chmod(so, mode, cred, td);
+	else
+		error = EINVAL;
+	return (error);
+}
+
 static int
 soo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
 {
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -484,6 +484,7 @@
 	unp->unp_socket = so;
 	so->so_pcb = unp;
 	refcount_init(&unp->unp_refcount, 1);
+	unp->unp_mode = ACCESSPERMS;
 
 	if ((locked = UNP_LINK_WOWNED()) == false)
 		UNP_LINK_WLOCK();
@@ -526,6 +527,7 @@
 	struct mount *mp;
 	cap_rights_t rights;
 	char *buf;
+	mode_t mode;
 
 	if (nam->sa_family != AF_UNIX)
 		return (EAFNOSUPPORT);
@@ -558,6 +560,7 @@
 		return (EALREADY);
 	}
 	unp->unp_flags |= UNP_BINDING;
+	mode = unp->unp_mode;
 	UNP_PCB_UNLOCK(unp);
 
 	buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
@@ -590,7 +593,7 @@
 	}
 	VATTR_NULL(&vattr);
 	vattr.va_type = VSOCK;
-	vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_pd->pd_cmask);
+	vattr.va_mode = (mode & ~td->td_proc->p_pd->pd_cmask);
 #ifdef MAC
 	error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
 	    &vattr);
@@ -702,6 +705,26 @@
 	}
 }
 
+static int
+uipc_chmod(struct socket *so, mode_t mode, struct ucred *cred __unused,
+    struct thread *td __unused)
+{
+	struct unpcb *unp;
+	int error;
+
+	unp = sotounpcb(so);
+
+	error = 0;
+	UNP_PCB_LOCK(unp);
+	if (unp->unp_vnode == NULL || (unp->unp_flags & UNP_BINDING) != 0 ||
+	    (mode & ~ACCESSPERMS) != 0)
+		error = EINVAL;
+	else
+		unp->unp_mode = mode;
+	UNP_PCB_UNLOCK(unp);
+	return (error);
+}
+
 static int
 uipc_connect2(struct socket *so1, struct socket *so2)
 {
@@ -3357,6 +3380,7 @@
 	.pr_sockaddr =		uipc_sockaddr,
 	.pr_soreceive =		soreceive_generic,
 	.pr_close =		uipc_close,
+	.pr_chmod =		uipc_chmod,
 };
 
 static struct protosw dgramproto = {
@@ -3380,6 +3404,7 @@
 	.pr_sockaddr =		uipc_sockaddr,
 	.pr_soreceive =		uipc_soreceive_dgram,
 	.pr_close =		uipc_close,
+	.pr_chmod =		uipc_chmod,
 };
 
 static struct protosw seqpacketproto = {
@@ -3411,6 +3436,7 @@
 	.pr_sockaddr =		uipc_sockaddr,
 	.pr_soreceive =		soreceive_generic,	/* XXX: or...? */
 	.pr_close =		uipc_close,
+	.pr_chmod =		uipc_chmod,
 };
 
 static struct domain localdomain = {
diff --git a/sys/sys/protosw.h b/sys/sys/protosw.h
--- a/sys/sys/protosw.h
+++ b/sys/sys/protosw.h
@@ -32,6 +32,8 @@
 #ifndef _SYS_PROTOSW_H_
 #define _SYS_PROTOSW_H_
 
+#include <sys/types.h>
+
 /* Forward declare these structures referenced from prototypes below. */
 struct kaiocb;
 struct mbuf;
@@ -100,6 +102,8 @@
 typedef int	pr_connectat_t(int, struct socket *, struct sockaddr *,
 		    struct thread *);
 typedef int	pr_aio_queue_t(struct socket *, struct kaiocb *);
+typedef int	pr_chmod_t(struct socket *, __mode_t, struct ucred *,
+		    struct thread *);
 
 struct protosw {
 	short	pr_type;		/* socket type used for */
@@ -139,6 +143,7 @@
 	pr_sense_t	*pr_sense;	/* stat(2) */
 	pr_sosetlabel_t	*pr_sosetlabel;	/* MAC, XXXGL: remove */
 	pr_setsbopt_t	*pr_setsbopt;	/* Socket buffer ioctls */
+	pr_chmod_t	*pr_chmod;	/* fchmod(2) */
 };
 /*#endif*/
 
diff --git a/sys/sys/unpcb.h b/sys/sys/unpcb.h
--- a/sys/sys/unpcb.h
+++ b/sys/sys/unpcb.h
@@ -93,6 +93,7 @@
 	u_int	unp_msgcount;		/* (g) references from message queue */
 	u_int	unp_gcrefs;		/* (g) garbage collector refcount */
 	ino_t	unp_ino;		/* (g) fake inode number */
+	mode_t  unp_mode;		/* (g) initial pre-bind() mode */
 	LIST_ENTRY(unpcb) unp_dead;	/* (g) link in dead list */
 } __aligned(CACHE_LINE_SIZE);