In unveil_add_vnode() refactor code around the indexes i and j. In one

place the wrong index is used resulting in re-evaluating all unveil nodes.
Also loop over over all but the last (just added vnode) -- again there is
no need to re-evaluate the cover of the just added unveil.
OK anton@ semarie@

diff --git a/sys/kern/kern_unveil.c b/sys/kern/kern_unveil.c
index 90b078b..782749a 100644 (file)
--- a/sys/kern/kern_unveil.c
+++ b/sys/kern/kern_unveil.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_unveil.c,v 1.42 2021/06/15 18:42:23 claudio Exp $        */
+/*     $OpenBSD: kern_unveil.c,v 1.43 2021/06/23 14:09:01 claudio Exp $        */
 
 /*
  * Copyright (c) 2017-2019 Bob Beck <beck@openbsd.org>
@@ -420,12 +420,11 @@ unveil_add_vnode(struct proc *p, struct vnode *vp)
 {
        struct process *pr = p->p_p;
        struct unveil *uv = NULL;
-       ssize_t i, j;
+       ssize_t i;
 
        KASSERT(pr->ps_uvvcount < UNVEIL_MAX_VNODES);
 
-       i = pr->ps_uvvcount;
-       uv = &pr->ps_uvpaths[i];
+       uv = &pr->ps_uvpaths[pr->ps_uvvcount++];
        rw_init(&uv->uv_lock, "unveil");
        RBT_INIT(unvname_rbt, &uv->uv_names);
        uv->uv_vp = vp;
@@ -438,7 +437,6 @@ unveil_add_vnode(struct proc *p, struct vnode *vp)
         * work.
         */
        uv->uv_flags = UNVEIL_INSPECT;
-       pr->ps_uvvcount++;
 
        /* find out what we are covered by */
        uv->uv_cover = unveil_find_cover(vp, p);
@@ -448,10 +446,10 @@ unveil_add_vnode(struct proc *p, struct vnode *vp)
         * and re-check what covers them (we could have
         * interposed a cover)
         */
-       for (j = 0; j < pr->ps_uvvcount; j++) {
+       for (i = 0; i < pr->ps_uvvcount - 1; i++) {
                if (pr->ps_uvpaths[i].uv_cover == uv->uv_cover)
-                       pr->ps_uvpaths[j].uv_cover =
-                           unveil_find_cover(pr->ps_uvpaths[j].uv_vp, p);
+                       pr->ps_uvpaths[i].uv_cover =
+                           unveil_find_cover(pr->ps_uvpaths[i].uv_vp, p);
        }
 
        return (uv);