bindat(2)/connectat(2): allow implicit EMPTYPATH for unix domain sockets

path specification.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D57370

sys/kern/uipc_usrreq.c

@@ -612,8 +612,9 @@ uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
 	buf[namelen] = 0;
 
 restart:
-	NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | NOCACHE,
-	    UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_BINDAT));
+	NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | NOCACHE |
+	    EMPTYPATH, UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights,
+	    CAP_BINDAT));
 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
 	error = namei(&nd);
 	if (error)
@@ -2921,7 +2922,7 @@ unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
 		sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
 	else
 		sa = NULL;
-	NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
+	NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF | EMPTYPATH,
 	    UIO_SYSSPACE, buf, fd, cap_rights_init_one(&rights, CAP_CONNECTAT));
 	error = namei(&nd);
 	if (error)