Index: vfs_syscalls.c
===================================================================
RCS file: /home/cvsup/freebsd/CVS/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.76
retrieving revision 1.77
diff -u -r1.76 -r1.77
--- vfs_syscalls.c	1997/10/12 20:24:27	1.76
+++ vfs_syscalls.c	1997/10/22 07:28:51	1.77
@@ -863,11 +863,13 @@
 	struct flock lf;
 	struct nameidata nd;
 
+	flags = FFLAGS(SCARG(uap, flags));
+	if ((flags & FREAD + FWRITE) == 0)
+		return (EINVAL);
 	error = falloc(p, &nfp, &indx);
 	if (error)
 		return (error);
 	fp = nfp;
-	flags = FFLAGS(SCARG(uap, flags));
 	cmode = ((SCARG(uap, mode) &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
 	p->p_dupfd = -indx - 1;			/* XXX check for fdopen */