OSX/sec/securityd/policytree.c

   1 /*
   2  * Copyright (c) 2009-2010,2012,2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * policytree.c - rfc5280 section 6.1.2 and later policy_tree implementation.
  26  */
  27
  28 #include "policytree.h"
  29 #include <libDER/oidsPriv.h>
  30
  31 #include <utilities/debugging.h>
  32
  33 #include <stdlib.h>
  34
  35 #define DUMP_POLICY_TREE  0
  36
  37 #if !defined(DUMP_POLICY_TREE)
  38 #include <stdio.h>
  39 #endif
  40
  41 static policy_set_t policy_set_create(const oid_t *p_oid) {
  42     policy_set_t policy_set =
  43         (policy_set_t)malloc(sizeof(*policy_set));
  44     policy_set->oid_next = NULL;
  45     policy_set->oid = *p_oid;
  46     secdebug("policy-set", "%p", policy_set);
  47     return policy_set;
  48 }
  49
  50 void policy_set_add(policy_set_t *policy_set, const oid_t *p_oid) {
  51     policy_set_t node = (policy_set_t)malloc(sizeof(*node));
  52     node->oid_next = *policy_set;
  53     node->oid = *p_oid;
  54     *policy_set = node;
  55     secdebug("policy-set", "%p -> %p", node, node->oid_next);
  56 }
  57
  58 void policy_set_free(policy_set_t node) {
  59     while (node) {
  60         policy_set_t next = node->oid_next;
  61         secdebug("policy-set", "%p -> %p", node, next);
  62         free(node);
  63         node = next;
  64     }
  65 }
  66
  67 bool policy_set_contains(policy_set_t node, const oid_t *oid) {
  68     for (; node;  node = node->oid_next) {
  69         if (oid_equal(node->oid, *oid))
  70             return true;
  71     }
  72     return false;
  73 }
  74
  75 void policy_set_intersect(policy_set_t *policy_set, policy_set_t other_set) {
  76     bool other_has_any = policy_set_contains(other_set, &oidAnyPolicy);
  77     if (policy_set_contains(*policy_set, &oidAnyPolicy)) {
  78         policy_set_t node = other_set;
  79         if (other_has_any) {
  80             /* Both sets contain anyPolicy so the intersection is anyPolicy
  81                plus all oids in either set.  */
  82             while (node) {
  83                 if (!policy_set_contains(*policy_set, &node->oid)) {
  84                     policy_set_add(policy_set, &node->oid);
  85                 }
  86             }
  87         } else {
  88             /* The result set contains anyPolicy and other_set doesn't. The
  89                result set should be a copy of other_set.  */
  90             policy_set_free(*policy_set);
  91             *policy_set = NULL;
  92             while (node) {
  93                 policy_set_add(policy_set, &node->oid);
  94             }
  95         }
  96     } else if (!other_has_any) {
  97         /* Neither set contains any policy oid so remove any values from the
  98            result set that aren't in other_set. */
  99         policy_set_t *pnode = policy_set;
 100         while (*pnode) {
 101             policy_set_t node = *pnode;
 102             if (policy_set_contains(other_set, &node->oid)) {
 103                 pnode = &node->oid_next;
 104             } else {
 105                 *pnode = node->oid_next;
 106                 node->oid_next = NULL;
 107                 policy_set_free(node);
 108             }
 109         }
 110     }
 111 }
 112
 113 policy_tree_t policy_tree_create(const oid_t *p_oid, policy_qualifier_t p_q) {
 114     policy_tree_t node = malloc(sizeof(*node));
 115     memset(node, 0, sizeof(*node));
 116     node->valid_policy = *p_oid;
 117     node->qualifier_set = p_q;
 118     node->expected_policy_set = policy_set_create(p_oid);
 119     secdebug("policy-node", "%p", node);
 120     return node;
 121 }
 122
 123 /* Walk the nodes in a tree at depth and invoke callback for each one. */
 124 bool policy_tree_walk_depth(policy_tree_t root, int depth,
 125     bool(*callback)(policy_tree_t, void *), void *ctx) {
 126     policy_tree_t stack[depth + 1];
 127     int stack_ix = 0;
 128     stack[stack_ix] = root;
 129     policy_tree_t node;
 130     bool match = false;
 131     bool child_visited = false;
 132     while (stack_ix >= 0) {
 133         /* stack[stack_ix - 1] is the parent of the current node. */
 134         node = stack[stack_ix];
 135         policy_tree_t child = node->children;
 136         if (!child_visited && stack_ix < depth && child ) {
 137             /* If we have a child and we haven't reached the
 138                required depth yet, we go depth first and proccess it. */
 139             stack[++stack_ix] = child;
 140         } else {
 141             /* Get the sibling now in case we delete the node in the callback */
 142             policy_tree_t sibling = node->siblings;
 143             if (stack_ix == depth) {
 144                 /* Proccess node. */
 145                 match |= callback(node, ctx);
 146             }
 147
 148             /* Move on to sibling of node. */
 149             if (sibling) {
 150                 /* Replace current node with it's sibling. */
 151                 stack[stack_ix] = sibling;
 152                 child_visited = false;
 153             } else {
 154                 /* No more siblings left, so pop the stack and backtrack. */
 155                 stack_ix--;
 156                 /* We've handled the top of the stack's child already so
 157                    just look at it's siblings. */
 158                 child_visited = true;
 159             }
 160         }
 161     }
 162     return match;
 163 }
 164
 165 static void policy_tree_free_node(policy_tree_t node) {
 166     secdebug("policy-node", "%p children: %p siblngs: %p", node,
 167         node->children, node->siblings);
 168     if (node->expected_policy_set) {
 169         policy_set_free(node->expected_policy_set);
 170         node->expected_policy_set = NULL;
 171     }
 172     free(node);
 173 }
 174
 175 void policy_tree_remove_node(policy_tree_t *node) {
 176     /* Free node's children */
 177     policy_tree_t *child = &(*node)->children;
 178     if (*child)
 179         policy_tree_prune(child);
 180
 181     /* Remove node from parent */
 182     policy_tree_t parent = (*node)->parent;
 183     parent->children = (*node)->siblings;
 184
 185     /* Free node */
 186     policy_tree_free_node(*node);
 187     *node = NULL;
 188 }
 189
 190 /* Prune nodes from node down. */
 191 void policy_tree_prune(policy_tree_t *node) {
 192     /* Free all our children and siblings. */
 193     policy_tree_t *child = &(*node)->children;
 194     if (*child)
 195         policy_tree_prune(child);
 196     policy_tree_t *sibling = &(*node)->siblings;
 197     if (*sibling)
 198         policy_tree_prune(sibling);
 199     policy_tree_free_node(*node);
 200     *node = NULL;
 201 }
 202
 203 /* Prune childless nodes at depth. */
 204 void policy_tree_prune_childless(policy_tree_t *root, int depth) {
 205     policy_tree_t *stack[depth + 1];
 206     int stack_ix = 0;
 207     stack[stack_ix] = root;
 208     bool child_visited = false;
 209     while (stack_ix >= 0) {
 210         policy_tree_t *node;
 211         node = stack[stack_ix];
 212         policy_tree_t *child = &(*node)->children;
 213         if (!child_visited && stack_ix < depth && *child) {
 214             /* If we have a child and we haven't reached the
 215                required depth yet, we go depth first and proccess it. */
 216             stack[++stack_ix] = child;
 217         } else if (!*child) {
 218             /* Childless node found, nuke it. */
 219 #if !defined(DUMP_POLICY_TREE)
 220             printf("# prune /<%.08lx<\\ |%.08lx| >%.08lx> :%s: depth %d\n",
 221                 (intptr_t)node, (intptr_t)*node, (intptr_t)(*node)->siblings,
 222                 (child_visited ? "v" : " "), stack_ix);
 223 #endif
 224
 225             policy_tree_t next = (*node)->siblings;
 226             (*node)->siblings = NULL;
 227             policy_tree_free_node(*node);
 228             *node = next;
 229             if (next) {
 230                 /* stack[stack_ix] (node) already points to next now. */
 231                 child_visited = false;
 232             } else {
 233                 /* No more siblings left, so pop the stack and backtrack. */
 234                 stack_ix--;
 235                 child_visited = true;
 236             }
 237         } else {
 238             policy_tree_t *sibling = &(*node)->siblings;
 239             if (*sibling) {
 240                 /* Replace current node with it's sibling. */
 241                 stack[stack_ix] = sibling;
 242                 child_visited = false;
 243             } else {
 244                 /* No more siblings left, so pop the stack and backtrack. */
 245                 stack_ix--;
 246                 child_visited = true;
 247             }
 248         }
 249     }
 250 }
 251
 252 /* Add a new child to the tree. */
 253 static void policy_tree_add_child_explicit(policy_tree_t parent,
 254     const oid_t *p_oid, policy_qualifier_t p_q, policy_set_t p_expected) {
 255     policy_tree_t child = malloc(sizeof(*child));
 256     memset(child, 0, sizeof(*child));
 257     child->valid_policy = *p_oid;
 258     child->qualifier_set = p_q;
 259     child->expected_policy_set = p_expected;
 260     child->parent = parent;
 261
 262 #if 0
 263     printf("# /%.08lx\\ |%.08lx| \\%.08lx/ >%.08lx> \\>%.08lx>/\n",
 264         (intptr_t)parent, (intptr_t)child, (intptr_t)parent->children,
 265         (intptr_t)parent->siblings,
 266         (intptr_t)(parent->children ? parent->children->siblings : NULL));
 267 #endif
 268
 269     /* Previous child becomes new child's first sibling. */
 270     child->siblings = parent->children;
 271     /* New child becomes parent's first child. */
 272     parent->children = child;
 273
 274     secdebug("policy-node", "%p siblngs: %p", child, child->siblings);
 275 }
 276
 277 /* Add a new child to the tree parent setting valid_policy to p_oid,
 278    qualifier_set to p_q and expected_policy_set to a set containing
 279    just p_oid. */
 280 void policy_tree_add_child(policy_tree_t parent,
 281     const oid_t *p_oid, policy_qualifier_t p_q) {
 282     policy_set_t policy_set = policy_set_create(p_oid);
 283     policy_tree_add_child_explicit(parent, p_oid, p_q, policy_set);
 284 }
 285
 286 /* Add a new sibling to the tree setting valid_policy to p_oid,
 287    qualifier set to p_q and expected_policy_set to p_expected */
 288 void policy_tree_add_sibling(policy_tree_t sibling, const oid_t *p_oid,
 289                              policy_qualifier_t p_q, policy_set_t p_expected) {
 290     policy_tree_add_child_explicit(sibling->parent, p_oid, p_q, p_expected);
 291 }
 292
 293 void policy_tree_set_expected_policy(policy_tree_t node,
 294     policy_set_t p_expected) {
 295     if (node->expected_policy_set)
 296         policy_set_free(node->expected_policy_set);
 297     node->expected_policy_set = p_expected;
 298 }
 299
 300 #if !defined(DUMP_POLICY_TREE)
 301 /* Dump a policy tree. */
 302 static void policy_tree_dump4(policy_tree_t node, policy_tree_t parent,
 303     policy_tree_t prev_sibling, int depth) {
 304     policy_tree_t child = node->children;
 305     policy_tree_t sibling = node->siblings;
 306     static const char *spaces = "                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        ";
 307     printf("# %.*s/%.08lx\\ |%.08lx| <%.08lx< >%.08lx> depth %d\n",
 308         depth * 11, spaces,
 309         (intptr_t)parent, (intptr_t)node, (intptr_t)prev_sibling,
 310         (intptr_t)sibling, depth);
 311     if (child)
 312         policy_tree_dump4(child, node, NULL, depth + 1);
 313     if (sibling)
 314         policy_tree_dump4(sibling, parent, node, depth);
 315 }
 316 #endif /* !defined(DUMP_POLICY_TREE) */
 317
 318 void policy_tree_dump(policy_tree_t node) {
 319 #if !defined(DUMP_POLICY_TREE)
 320     policy_tree_dump4(node, NULL, NULL, 0);
 321 #endif /* !defined(DUMP_POLICY_TREE) */
 322 }