Remove the uvshrink logic and keep the unveil list in the order of insertion.

unveil_lookup() is now doing a dumb linear search. The problem with the
uvshrink logic was that ps_uvpcwd was a pointer into this array and after
compation it pointed to the wrong element. Also future unveil caches would
suffer from the same issue.
OK semarie@

diff --git a/sys/kern/kern_unveil.c b/sys/kern/kern_unveil.c
index d45b26f..90b078b 100644 (file)
--- a/sys/kern/kern_unveil.c
+++ b/sys/kern/kern_unveil.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_unveil.c,v 1.41 2021/06/09 17:52:47 semarie Exp $        */
+/*     $OpenBSD: kern_unveil.c,v 1.42 2021/06/15 18:42:23 claudio Exp $        */
 
 /*
  * Copyright (c) 2017-2019 Bob Beck <beck@openbsd.org>
@@ -270,7 +270,6 @@ unveil_copy(struct process *parent, struct process *child)
                child->ps_uvpcwd = child->ps_uvpaths +
                    (parent->ps_uvpcwd - parent->ps_uvpaths);
        child->ps_uvdone = parent->ps_uvdone;
-       child->ps_uvshrink = parent->ps_uvshrink;
 }
 
 /*
@@ -353,65 +352,22 @@ struct unveil *
 unveil_lookup(struct vnode *vp, struct process *pr, ssize_t *position)
 {
        struct unveil *uv = pr->ps_uvpaths;
-       ssize_t l, r;
+       ssize_t i;
+
        if (position != NULL)
                *position = -1;
 
        if (vp->v_uvcount == 0)
                return NULL;
 
-       /*
-        * shrink if told to do so to remove dead vnodes.
-        */
-       if (pr->ps_uvshrink) {
-               size_t i = 0, j;
-
-               while (i < pr->ps_uvvcount) {
-                       if (uv[i].uv_vp == NULL)  {
-                               pr->ps_uvncount -= unveil_delete_names(&uv[i]);
-                               for (j = i + 1; j < pr->ps_uvvcount; j++)
-                                       uv[j - 1] = uv[j];
-                               pr->ps_uvvcount--;
-                               for (j = 0; j < pr->ps_uvvcount; j++) {
-                                       if (uv[j].uv_cover == i) {
-                                               /*
-                                                * anything covered by
-                                                * this one will be nuked
-                                                * on unmount as well.
-                                                */
-                                               uv[j].uv_cover = -1;
-                                       }
-                                       else if (uv[j].uv_cover > i)
-                                               uv[j].uv_cover--;
-                               }
-                       }
-                       i++;
-               }
-               pr->ps_uvshrink = 0;
-       }
-
-       if (pr->ps_uvvcount == 0)
-               return NULL;
-
-       l = 0;
-       r = pr->ps_uvvcount - 1;
-       while (l <= r) {
-               size_t m = l + (r - l)/2;
-#ifdef DEBUG_UNVEIL
-               printf("unveil: checking vnode %p vs. unveil vnode %p\n",
-                  vp, uv[m].uv_vp);
-#endif
-               if (vp == uv[m].uv_vp) {
-                       KASSERT(uv[m].uv_vp->v_uvcount > 0);
-                       KASSERT(uv[m].uv_vp->v_usecount > 0);
+       for (i = 0; i < pr->ps_uvvcount; i++) {
+               if (vp == uv[i].uv_vp) {
+                       KASSERT(uv[i].uv_vp->v_uvcount > 0);
+                       KASSERT(uv[i].uv_vp->v_usecount > 0);
                        if (position != NULL)
-                               *position = m;
-                       return &uv[m];
+                               *position = i;
+                       return &uv[i];
                }
-               if (vp > uv[m].uv_vp)
-                       l = m + 1;
-               else
-                       r = m - 1;
        }
        return NULL;
 }
@@ -468,18 +424,7 @@ unveil_add_vnode(struct proc *p, struct vnode *vp)
 
        KASSERT(pr->ps_uvvcount < UNVEIL_MAX_VNODES);
 
-       for (i = pr->ps_uvvcount;
-            i > 0 && pr->ps_uvpaths[i - 1].uv_vp > vp;
-            i--) {
-               pr->ps_uvpaths[i] = pr->ps_uvpaths[i - 1];
-       }
-
-       /* adjust the covers to account for our addition  */
-       for (j = 0; j < pr->ps_uvvcount; j++) {
-               if (pr->ps_uvpaths[i].uv_cover >= i)
-                       pr->ps_uvpaths[i].uv_cover++;
-       }
-
+       i = pr->ps_uvvcount;
        uv = &pr->ps_uvpaths[i];
        rw_init(&uv->uv_lock, "unveil");
        RBT_INIT(unvname_rbt, &uv->uv_names);
@@ -997,7 +942,6 @@ unveil_removevnode(struct vnode *vp)
                        printf("unveil_removevnode vnode %p now count %d\n",
                            vp, vp->v_uvcount);
 #endif
-                       pr->ps_uvshrink = 1;
                        if (vp->v_uvcount > 0) {
                                vrele(vp);
                                vp->v_uvcount--;

diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index 75ae18c..15459cc 100644 (file)
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: proc.h,v 1.312 2021/05/12 08:09:33 mvs Exp $  */
+/*     $OpenBSD: proc.h,v 1.313 2021/06/15 18:42:23 claudio Exp $      */
 /*     $NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $       */
 
 /*-
@@ -230,10 +230,9 @@ struct process {
 
        struct unveil *ps_uvpaths;      /* unveil vnodes and names */
        struct unveil *ps_uvpcwd;       /* pointer to unveil of cwd, NULL if none */
-       ssize_t ps_uvvcount;            /* count of unveil vnodes held */
-       size_t ps_uvncount;             /* count of unveil names allocated */
-       int ps_uvshrink;                /* do we need to shrink vnode list */
-       int ps_uvdone;                  /* no more unveil is permitted */
+       ssize_t ps_uvvcount;            /* count of unveil vnodes held */
+       size_t  ps_uvncount;            /* count of unveil names allocated */
+       int     ps_uvdone;              /* no more unveil is permitted */
 
 /* End area that is zeroed on creation. */
 #define        ps_endzero      ps_startcopy