/* $OpenBSD: pcy_tree.c,v 1.1 2020/06/04 15:19:31 jsing Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project 2004.
*/
/* ====================================================================
* Copyright (c) 2004 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* licensing@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include "pcy_int.h"
/* Enable this to print out the complete policy tree at various point during
* evaluation.
*/
/*#define OPENSSL_POLICY_DEBUG*/
#ifdef OPENSSL_POLICY_DEBUG
static void
expected_print(BIO *err, X509_POLICY_LEVEL *lev, X509_POLICY_NODE *node,
int indent)
{
if ((lev->flags & X509_V_FLAG_INHIBIT_MAP) ||
!(node->data->flags & POLICY_DATA_FLAG_MAP_MASK))
BIO_puts(err, " Not Mapped\n");
else {
int i;
STACK_OF(ASN1_OBJECT) *pset = node->data->expected_policy_set;
ASN1_OBJECT *oid;
BIO_puts(err, " Expected: ");
for (i = 0; i < sk_ASN1_OBJECT_num(pset); i++) {
oid = sk_ASN1_OBJECT_value(pset, i);
if (i)
BIO_puts(err, ", ");
i2a_ASN1_OBJECT(err, oid);
}
BIO_puts(err, "\n");
}
}
static void
tree_print(char *str, X509_POLICY_TREE *tree, X509_POLICY_LEVEL *curr)
{
X509_POLICY_LEVEL *plev;
X509_POLICY_NODE *node;
int i;
BIO *err;
if ((err = BIO_new_fp(stderr, BIO_NOCLOSE)) == NULL)
return;
if (!curr)
curr = tree->levels + tree->nlevel;
else
curr++;
BIO_printf(err, "Level print after %s\n", str);
BIO_printf(err, "Printing Up to Level %ld\n", curr - tree->levels);
for (plev = tree->levels; plev != curr; plev++) {
BIO_printf(err, "Level %ld, flags = %x\n",
plev - tree->levels, plev->flags);
for (i = 0; i < sk_X509_POLICY_NODE_num(plev->nodes); i++) {
node = sk_X509_POLICY_NODE_value(plev->nodes, i);
X509_POLICY_NODE_print(err, node, 2);
expected_print(err, plev, node, 2);
BIO_printf(err, " Flags: %x\n", node->data->flags);
}
if (plev->anyPolicy)
X509_POLICY_NODE_print(err, plev->anyPolicy, 2);
}
BIO_free(err);
}
#else
#define tree_print(a,b,c) /* */
#endif
/* Initialize policy tree. Return values:
* 0 Some internal error occured.
* -1 Inconsistent or invalid extensions in certificates.
* 1 Tree initialized OK.
* 2 Policy tree is empty.
* 5 Tree OK and requireExplicitPolicy true.
* 6 Tree empty and requireExplicitPolicy true.
*/
static int
tree_init(X509_POLICY_TREE **ptree, STACK_OF(X509) *certs, unsigned int flags)
{
X509_POLICY_TREE *tree;
X509_POLICY_LEVEL *level;
const X509_POLICY_CACHE *cache;
X509_POLICY_DATA *data = NULL;
X509 *x;
int ret = 1;
int i, n;
int explicit_policy;
int any_skip;
int map_skip;
*ptree = NULL;
n = sk_X509_num(certs);
if (flags & X509_V_FLAG_EXPLICIT_POLICY)
explicit_policy = 0;
else
explicit_policy = n + 1;
if (flags & X509_V_FLAG_INHIBIT_ANY)
any_skip = 0;
else
any_skip = n + 1;
if (flags & X509_V_FLAG_INHIBIT_MAP)
map_skip = 0;
else
map_skip = n + 1;
/* Can't do anything with just a trust anchor */
if (n == 1)
return 1;
/* First setup policy cache in all certificates apart from the
* trust anchor. Note any bad cache results on the way. Also can
* calculate explicit_policy value at this point.
*/
for (i = n - 2; i >= 0; i--) {
x = sk_X509_value(certs, i);
X509_check_purpose(x, -1, -1);
cache = policy_cache_set(x);
/* If cache NULL something bad happened: return immediately */
if (cache == NULL)
return 0;
/* If inconsistent extensions keep a note of it but continue */
if (x->ex_flags & EXFLAG_INVALID_POLICY)
ret = -1;
/* Otherwise if we have no data (hence no CertificatePolicies)
* and haven't already set an inconsistent code note it.
*/
else if ((ret == 1) && !cache->data)
ret = 2;
if (explicit_policy > 0) {
if (!(x->ex_flags & EXFLAG_SI))
explicit_policy--;
if ((cache->explicit_skip != -1) &&
(cache->explicit_skip < explicit_policy))
explicit_policy = cache->explicit_skip;
}
}
if (ret != 1) {
if (ret == 2 && !explicit_policy)
return 6;
return ret;
}
/* If we get this far initialize the tree */
tree = malloc(sizeof(X509_POLICY_TREE));
if (!tree)
return 0;
tree->flags = 0;
tree->levels = calloc(n, sizeof(X509_POLICY_LEVEL));
tree->nlevel = 0;
tree->extra_data = NULL;
tree->auth_policies = NULL;
tree->user_policies = NULL;
if (!tree->levels) {
free(tree);
return 0;
}
tree->nlevel = n;
level = tree->levels;
/* Root data: initialize to anyPolicy */
data = policy_data_new(NULL, OBJ_nid2obj(NID_any_policy), 0);
if (!data || !level_add_node(level, data, NULL, tree, NULL))
goto bad_tree;
for (i = n - 2; i >= 0; i--) {
level++;
x = sk_X509_value(certs, i);
cache = policy_cache_set(x);
CRYPTO_add(&x->references, 1, CRYPTO_LOCK_X509);
level->cert = x;
if (!cache->anyPolicy)
level->flags |= X509_V_FLAG_INHIBIT_ANY;
/* Determine inhibit any and inhibit map flags */
if (any_skip == 0) {
/* Any matching allowed if certificate is self
* issued and not the last in the chain.
*/
if (!(x->ex_flags & EXFLAG_SI) || (i == 0))
level->flags |= X509_V_FLAG_INHIBIT_ANY;
} else {
if (!(x->ex_flags & EXFLAG_SI))
any_skip--;
if ((cache->any_skip >= 0) &&
(cache->any_skip < any_skip))
any_skip = cache->any_skip;
}
if (map_skip == 0)
level->flags |= X509_V_FLAG_INHIBIT_MAP;
else {
if (!(x->ex_flags & EXFLAG_SI))
map_skip--;
if ((cache->map_skip >= 0) &&
(cache->map_skip < map_skip))
map_skip = cache->map_skip;
}
}
*ptree = tree;
if (explicit_policy)
return 1;
else
return 5;
bad_tree:
X509_policy_tree_free(tree);
return 0;
}
static int
tree_link_matching_nodes(X509_POLICY_LEVEL *curr, const X509_POLICY_DATA *data)
{
X509_POLICY_LEVEL *last = curr - 1;
X509_POLICY_NODE *node;
int i, matched = 0;
/* Iterate through all in nodes linking matches */
for (i = 0; i < sk_X509_POLICY_NODE_num(last->nodes); i++) {
node = sk_X509_POLICY_NODE_value(last->nodes, i);
if (policy_node_match(last, node, data->valid_policy)) {
if (!level_add_node(curr, data, node, NULL, NULL))
return 0;
matched = 1;
}
}
if (!matched && last->anyPolicy) {
if (!level_add_node(curr, data, last->anyPolicy, NULL, NULL))
return 0;
}
return 1;
}
/* This corresponds to RFC3280 6.1.3(d)(1):
* link any data from CertificatePolicies onto matching parent
* or anyPolicy if no match.
*/
static int
tree_link_nodes(X509_POLICY_LEVEL *curr, const X509_POLICY_CACHE *cache)
{
int i;
X509_POLICY_DATA *data;
for (i = 0; i < sk_X509_POLICY_DATA_num(cache->data); i++) {
data = sk_X509_POLICY_DATA_value(cache->data, i);
/* Look for matching nodes in previous level */
if (!tree_link_matching_nodes(curr, data))
return 0;
}
return 1;
}
/* This corresponds to RFC3280 6.1.3(d)(2):
* Create new data for any unmatched policies in the parent and link
* to anyPolicy.
*/
static int
tree_add_unmatched(X509_POLICY_LEVEL *curr, const X509_POLICY_CACHE *cache,
const ASN1_OBJECT *id, X509_POLICY_NODE *node, X509_POLICY_TREE *tree)
{
X509_POLICY_DATA *data;
if (id == NULL)
id = node->data->valid_policy;
/* Create a new node with qualifiers from anyPolicy and
* id from unmatched node.
*/
data = policy_data_new(NULL, id, node_critical(node));
if (data == NULL)
return 0;
/* Curr may not have anyPolicy */
data->qualifier_set = cache->anyPolicy->qualifier_set;
data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;
if (!level_add_node(curr, data, node, tree, NULL)) {
policy_data_free(data);
return 0;
}
return 1;
}
static int
tree_link_unmatched(X509_POLICY_LEVEL *curr, const X509_POLICY_CACHE *cache,
X509_POLICY_NODE *node, X509_POLICY_TREE *tree)
{
const X509_POLICY_LEVEL *last = curr - 1;
int i;
if ((last->flags & X509_V_FLAG_INHIBIT_MAP) ||
!(node->data->flags & POLICY_DATA_FLAG_MAPPED)) {
/* If no policy mapping: matched if one child present */
if (node->nchild)
return 1;
if (!tree_add_unmatched(curr, cache, NULL, node, tree))
return 0;
/* Add it */
} else {
/* If mapping: matched if one child per expected policy set */
STACK_OF(ASN1_OBJECT) *expset = node->data->expected_policy_set;
if (node->nchild == sk_ASN1_OBJECT_num(expset))
return 1;
/* Locate unmatched nodes */
for (i = 0; i < sk_ASN1_OBJECT_num(expset); i++) {
ASN1_OBJECT *oid = sk_ASN1_OBJECT_value(expset, i);
if (level_find_node(curr, node, oid))
continue;
if (!tree_add_unmatched(curr, cache, oid, node, tree))
return 0;
}
}
return 1;
}
static int
tree_link_any(X509_POLICY_LEVEL *curr, const X509_POLICY_CACHE *cache,
X509_POLICY_TREE *tree)
{
int i;
X509_POLICY_NODE *node;
X509_POLICY_LEVEL *last = curr - 1;
for (i = 0; i < sk_X509_POLICY_NODE_num(last->nodes); i++) {
node = sk_X509_POLICY_NODE_value(last->nodes, i);
if (!tree_link_unmatched(curr, cache, node, tree))
return 0;
}
/* Finally add link to anyPolicy */
if (last->anyPolicy) {
if (!level_add_node(curr, cache->anyPolicy,
last->anyPolicy, NULL, NULL))
return 0;
}
return 1;
}
/* Prune the tree: delete any child mapped child data on the current level
* then proceed up the tree deleting any data with no children. If we ever
* have no data on a level we can halt because the tree will be empty.
*/
static int
tree_prune(X509_POLICY_TREE *tree, X509_POLICY_LEVEL *curr)
{
STACK_OF(X509_POLICY_NODE) *nodes;
X509_POLICY_NODE *node;
int i;
nodes = curr->nodes;
if (curr->flags & X509_V_FLAG_INHIBIT_MAP) {
for (i = sk_X509_POLICY_NODE_num(nodes) - 1; i >= 0; i--) {
node = sk_X509_POLICY_NODE_value(nodes, i);
/* Delete any mapped data: see RFC3280 XXXX */
if (node->data->flags & POLICY_DATA_FLAG_MAP_MASK) {
node->parent->nchild--;
free(node);
(void)sk_X509_POLICY_NODE_delete(nodes, i);
}
}
}
for (;;) {
--curr;
nodes = curr->nodes;
for (i = sk_X509_POLICY_NODE_num(nodes) - 1; i >= 0; i--) {
node = sk_X509_POLICY_NODE_value(nodes, i);
if (node->nchild == 0) {
node->parent->nchild--;
free(node);
(void)sk_X509_POLICY_NODE_delete(nodes, i);
}
}
if (curr->anyPolicy && !curr->anyPolicy->nchild) {
if (curr->anyPolicy->parent)
curr->anyPolicy->parent->nchild--;
free(curr->anyPolicy);
curr->anyPolicy = NULL;
}
if (curr == tree->levels) {
/* If we zapped anyPolicy at top then tree is empty */
if (!curr->anyPolicy)
return 2;
return 1;
}
}
return 1;
}
static int
tree_add_auth_node(STACK_OF(X509_POLICY_NODE) **pnodes, X509_POLICY_NODE *pcy)
{
if (!*pnodes) {
*pnodes = policy_node_cmp_new();
if (!*pnodes)
return 0;
} else if (sk_X509_POLICY_NODE_find(*pnodes, pcy) != -1)
return 1;
if (!sk_X509_POLICY_NODE_push(*pnodes, pcy))
return 0;
return 1;
}
/* Calculate the authority set based on policy tree.
* The 'pnodes' parameter is used as a store for the set of policy nodes
* used to calculate the user set. If the authority set is not anyPolicy
* then pnodes will just point to the authority set. If however the authority
* set is anyPolicy then the set of valid policies (other than anyPolicy)
* is store in pnodes. The return value of '2' is used in this case to indicate
* that pnodes should be freed.
*/
static int
tree_calculate_authority_set(X509_POLICY_TREE *tree,
STACK_OF(X509_POLICY_NODE) **pnodes)
{
X509_POLICY_LEVEL *curr;
X509_POLICY_NODE *node, *anyptr;
STACK_OF(X509_POLICY_NODE) **addnodes;
int i, j;
curr = tree->levels + tree->nlevel - 1;
/* If last level contains anyPolicy set is anyPolicy */
if (curr->anyPolicy) {
if (!tree_add_auth_node(&tree->auth_policies, curr->anyPolicy))
return 0;
addnodes = pnodes;
} else
/* Add policies to authority set */
addnodes = &tree->auth_policies;
curr = tree->levels;
for (i = 1; i < tree->nlevel; i++) {
/* If no anyPolicy node on this this level it can't
* appear on lower levels so end search.
*/
if (!(anyptr = curr->anyPolicy))
break;
curr++;
for (j = 0; j < sk_X509_POLICY_NODE_num(curr->nodes); j++) {
node = sk_X509_POLICY_NODE_value(curr->nodes, j);
if ((node->parent == anyptr) &&
!tree_add_auth_node(addnodes, node))
return 0;
}
}
if (addnodes == pnodes)
return 2;
*pnodes = tree->auth_policies;
return 1;
}
static int
tree_calculate_user_set(X509_POLICY_TREE *tree,
STACK_OF(ASN1_OBJECT) *policy_oids, STACK_OF(X509_POLICY_NODE) *auth_nodes)
{
int i;
X509_POLICY_NODE *node;
ASN1_OBJECT *oid;
X509_POLICY_NODE *anyPolicy;
X509_POLICY_DATA *extra;
/* Check if anyPolicy present in authority constrained policy set:
* this will happen if it is a leaf node.
*/
if (sk_ASN1_OBJECT_num(policy_oids) <= 0)
return 1;
anyPolicy = tree->levels[tree->nlevel - 1].anyPolicy;
for (i = 0; i < sk_ASN1_OBJECT_num(policy_oids); i++) {
oid = sk_ASN1_OBJECT_value(policy_oids, i);
if (OBJ_obj2nid(oid) == NID_any_policy) {
tree->flags |= POLICY_FLAG_ANY_POLICY;
return 1;
}
}
for (i = 0; i < sk_ASN1_OBJECT_num(policy_oids); i++) {
oid = sk_ASN1_OBJECT_value(policy_oids, i);
node = tree_find_sk(auth_nodes, oid);
if (!node) {
if (!anyPolicy)
continue;
/* Create a new node with policy ID from user set
* and qualifiers from anyPolicy.
*/
extra = policy_data_new(NULL, oid,
node_critical(anyPolicy));
if (!extra)
return 0;
extra->qualifier_set = anyPolicy->data->qualifier_set;
extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS |
POLICY_DATA_FLAG_EXTRA_NODE;
(void) level_add_node(NULL, extra, anyPolicy->parent,
tree, &node);
}
if (!tree->user_policies) {
tree->user_policies = sk_X509_POLICY_NODE_new_null();
if (!tree->user_policies)
return 1;
}
if (!sk_X509_POLICY_NODE_push(tree->user_policies, node))
return 0;
}
return 1;
}
static int
tree_evaluate(X509_POLICY_TREE *tree)
{
int ret, i;
X509_POLICY_LEVEL *curr = tree->levels + 1;
const X509_POLICY_CACHE *cache;
for (i = 1; i < tree->nlevel; i++, curr++) {
cache = policy_cache_set(curr->cert);
if (!tree_link_nodes(curr, cache))
return 0;
if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY) &&
!tree_link_any(curr, cache, tree))
return 0;
tree_print("before tree_prune()", tree, curr);
ret = tree_prune(tree, curr);
if (ret != 1)
return ret;
}
return 1;
}
static void
exnode_free(X509_POLICY_NODE *node)
{
if (node->data && (node->data->flags & POLICY_DATA_FLAG_EXTRA_NODE))
free(node);
}
void
X509_policy_tree_free(X509_POLICY_TREE *tree)
{
X509_POLICY_LEVEL *curr;
int i;
if (!tree)
return;
sk_X509_POLICY_NODE_free(tree->auth_policies);
sk_X509_POLICY_NODE_pop_free(tree->user_policies, exnode_free);
for (i = 0, curr = tree->levels; i < tree->nlevel; i++, curr++) {
X509_free(curr->cert);
if (curr->nodes)
sk_X509_POLICY_NODE_pop_free(curr->nodes,
policy_node_free);
if (curr->anyPolicy)
policy_node_free(curr->anyPolicy);
}
if (tree->extra_data)
sk_X509_POLICY_DATA_pop_free(tree->extra_data,
policy_data_free);
free(tree->levels);
free(tree);
}
/* Application policy checking function.
* Return codes:
* 0 Internal Error.
* 1 Successful.
* -1 One or more certificates contain invalid or inconsistent extensions
* -2 User constrained policy set empty and requireExplicit true.
*/
int
X509_policy_check(X509_POLICY_TREE **ptree, int *pexplicit_policy,
STACK_OF(X509) *certs, STACK_OF(ASN1_OBJECT) *policy_oids,
unsigned int flags)
{
int ret, ret2;
X509_POLICY_TREE *tree = NULL;
STACK_OF(X509_POLICY_NODE) *nodes, *auth_nodes = NULL;
*ptree = NULL;
*pexplicit_policy = 0;
ret = tree_init(&tree, certs, flags);
switch (ret) {
/* Tree empty requireExplicit False: OK */
case 2:
return 1;
/* Some internal error */
case -1:
return -1;
/* Some internal error */
case 0:
return 0;
/* Tree empty requireExplicit True: Error */
case 6:
*pexplicit_policy = 1;
return -2;
/* Tree OK requireExplicit True: OK and continue */
case 5:
*pexplicit_policy = 1;
break;
/* Tree OK: continue */
case 1:
if (!tree)
/*
* tree_init() returns success and a null tree
* if it's just looking at a trust anchor.
* I'm not sure that returning success here is
* correct, but I'm sure that reporting this
* as an internal error which our caller
* interprets as a malloc failure is wrong.
*/
return 1;
break;
}
if (!tree)
goto error;
ret = tree_evaluate(tree);
tree_print("tree_evaluate()", tree, NULL);
if (ret <= 0)
goto error;
/* Return value 2 means tree empty */
if (ret == 2) {
X509_policy_tree_free(tree);
if (*pexplicit_policy)
return -2;
else
return 1;
}
/* Tree is not empty: continue */
ret = tree_calculate_authority_set(tree, &auth_nodes);
if (ret == 0)
goto error;
ret2 = tree_calculate_user_set(tree, policy_oids, auth_nodes);
/* Return value 2 means auth_nodes needs to be freed */
if (ret == 2)
sk_X509_POLICY_NODE_free(auth_nodes);
if (ret2 == 0)
goto error;
if (tree)
*ptree = tree;
if (*pexplicit_policy) {
nodes = X509_policy_tree_get0_user_policies(tree);
if (sk_X509_POLICY_NODE_num(nodes) <= 0)
return -2;
}
return 1;
error:
X509_policy_tree_free(tree);
return 0;
}