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openssl/crypto/x509v3/pcy_tree.c

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/*
* Copyright 2004-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/cryptlib.h"
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include "pcy_local.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)
{
BIO *err = BIO_new_fp(stderr, BIO_NOCLOSE);
X509_POLICY_LEVEL *plev;
if (err == 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++) {
int i;
BIO_printf(err, "Level %ld, flags = %x\n",
(long)(plev - tree->levels), plev->flags);
for (i = 0; i < sk_X509_POLICY_NODE_num(plev->nodes); i++) {
X509_POLICY_NODE *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);
}
#endif
/*-
* Return value: <= 0 on error, or positive bit mask:
*
* X509_PCY_TREE_VALID: valid tree
* X509_PCY_TREE_EMPTY: empty tree (including bare TA case)
* X509_PCY_TREE_EXPLICIT: explicit policy required
*/
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;
int ret = X509_PCY_TREE_VALID;
int n = sk_X509_num(certs) - 1; /* RFC5280 paths omit the TA */
int explicit_policy = (flags & X509_V_FLAG_EXPLICIT_POLICY) ? 0 : n+1;
int any_skip = (flags & X509_V_FLAG_INHIBIT_ANY) ? 0 : n+1;
int map_skip = (flags & X509_V_FLAG_INHIBIT_MAP) ? 0 : n+1;
int i;
*ptree = NULL;
/* Can't do anything with just a trust anchor */
if (n == 0)
return X509_PCY_TREE_EMPTY;
/*
* First setup the policy cache in all n non-TA certificates, this will be
* used in X509_verify_cert() which will invoke the verify callback for all
* certificates with invalid policy extensions.
*/
for (i = n - 1; i >= 0; i--) {
X509 *x = sk_X509_value(certs, i);
/* Call for side-effect of computing hash and caching extensions */
X509_check_purpose(x, -1, 0);
/* If cache is NULL, likely ENOMEM: return immediately */
if (policy_cache_set(x) == NULL)
return X509_PCY_TREE_INTERNAL;
}
/*
* At this point check for invalid policies and required explicit policy.
* Note that the explicit_policy counter is a count-down to zero, with the
* requirement kicking in if and once it does that. The counter is
* decremented for every non-self-issued certificate in the path, but may
* be further reduced by policy constraints in a non-leaf certificate.
*
* The ultimate policy set is the intersection of all the policies along
* the path, if we hit a certificate with an empty policy set, and explicit
* policy is required we're done.
*/
for (i = n - 1;
i >= 0 && (explicit_policy > 0 || (ret & X509_PCY_TREE_EMPTY) == 0);
i--) {
X509 *x = sk_X509_value(certs, i);
uint32_t ex_flags = X509_get_extension_flags(x);
/* All the policies are already cached, we can return early */
if (ex_flags & EXFLAG_INVALID_POLICY)
return X509_PCY_TREE_INVALID;
/* Access the cache which we now know exists */
cache = policy_cache_set(x);
if ((ret & X509_PCY_TREE_VALID) && cache->data == NULL)
ret = X509_PCY_TREE_EMPTY;
if (explicit_policy > 0) {
if (!(ex_flags & EXFLAG_SI))
explicit_policy--;
if ((cache->explicit_skip >= 0)
&& (cache->explicit_skip < explicit_policy))
explicit_policy = cache->explicit_skip;
}
}
if (explicit_policy == 0)
ret |= X509_PCY_TREE_EXPLICIT;
if ((ret & X509_PCY_TREE_VALID) == 0)
return ret;
/* If we get this far initialize the tree */
if ((tree = OPENSSL_zalloc(sizeof(*tree))) == NULL) {
X509V3err(X509V3_F_TREE_INIT, ERR_R_MALLOC_FAILURE);
return X509_PCY_TREE_INTERNAL;
}
/*
* http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.
*
* The top level is implicitly for the trust anchor with valid expected
* policies of anyPolicy. (RFC 5280 has the TA at depth 0 and the leaf at
* depth n, we have the leaf at depth 0 and the TA at depth n).
*/
if ((tree->levels = OPENSSL_zalloc(sizeof(*tree->levels)*(n+1))) == NULL) {
OPENSSL_free(tree);
X509V3err(X509V3_F_TREE_INIT, ERR_R_MALLOC_FAILURE);
return X509_PCY_TREE_INTERNAL;
}
tree->nlevel = n+1;
level = tree->levels;
if ((data = policy_data_new(NULL, OBJ_nid2obj(NID_any_policy), 0)) == NULL)
goto bad_tree;
if (level_add_node(level, data, NULL, tree) == NULL) {
policy_data_free(data);
goto bad_tree;
}
/*
* In this pass initialize all the tree levels and whether anyPolicy and
* policy mapping are inhibited at each level.
*/
for (i = n - 1; i >= 0; i--) {
X509 *x = sk_X509_value(certs, i);
uint32_t ex_flags = X509_get_extension_flags(x);
/* Access the cache which we now know exists */
cache = policy_cache_set(x);
X509_up_ref(x);
(++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 only if certificate is self issued and not
* the last in the chain.
*/
if (!(ex_flags & EXFLAG_SI) || (i == 0))
level->flags |= X509_V_FLAG_INHIBIT_ANY;
} else {
if (!(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 (!(ex_flags & EXFLAG_SI))
map_skip--;
if ((cache->map_skip >= 0) && (cache->map_skip < map_skip))
map_skip = cache->map_skip;
}
}
*ptree = tree;
return ret;
bad_tree:
X509_policy_tree_free(tree);
return X509_PCY_TREE_INTERNAL;
}
/*
* Return value: 1 on success, 0 otherwise
*/
static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
X509_POLICY_DATA *data)
{
X509_POLICY_LEVEL *last = curr - 1;
int i, matched = 0;
/* Iterate through all in nodes linking matches */
for (i = 0; i < sk_X509_POLICY_NODE_num(last->nodes); i++) {
X509_POLICY_NODE *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.
*
* Return value: 1 on success, 0 otherwise.
*/
static int tree_link_nodes(X509_POLICY_LEVEL *curr,
const X509_POLICY_CACHE *cache)
{
int i;
for (i = 0; i < sk_X509_POLICY_DATA_num(cache->data); i++) {
X509_POLICY_DATA *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.
*
* Return value: 1 on success, 0 otherwise.
*/
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.
*/
if ((data = policy_data_new(NULL, id, node_critical(node))) == 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;
}
/*
* Return value: 1 on success, 0 otherwise.
*/
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;
}
/*
* Return value: 1 on success, 0 otherwise
*/
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 &&
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.
*
* Return value: <= 0 error, otherwise one of:
*
* X509_PCY_TREE_VALID: valid tree
* X509_PCY_TREE_EMPTY: empty tree
*/
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--;
OPENSSL_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--;
OPENSSL_free(node);
(void)sk_X509_POLICY_NODE_delete(nodes, i);
}
}
if (curr->anyPolicy && !curr->anyPolicy->nchild) {
if (curr->anyPolicy->parent)
curr->anyPolicy->parent->nchild--;
OPENSSL_free(curr->anyPolicy);
curr->anyPolicy = NULL;
}
if (curr == tree->levels) {
/* If we zapped anyPolicy at top then tree is empty */
if (!curr->anyPolicy)
return X509_PCY_TREE_EMPTY;
break;
}
}
return X509_PCY_TREE_VALID;
}
/*
* Return value: 1 on success, 0 otherwise.
*/
static int tree_add_auth_node(STACK_OF(X509_POLICY_NODE) **pnodes,
X509_POLICY_NODE *pcy)
{
if (*pnodes == NULL &&
(*pnodes = policy_node_cmp_new()) == NULL)
return 0;
if (sk_X509_POLICY_NODE_find(*pnodes, pcy) >= 0)
return 1;
return sk_X509_POLICY_NODE_push(*pnodes, pcy) != 0;
}
#define TREE_CALC_FAILURE 0
#define TREE_CALC_OK_NOFREE 1
#define TREE_CALC_OK_DOFREE 2
/*-
* 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.
*
* Return value:
* TREE_CALC_FAILURE on failure,
* TREE_CALC_OK_NOFREE on success and pnodes need not be freed,
* TREE_CALC_OK_DOFREE on success and pnodes needs to 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 TREE_CALC_FAILURE;
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) == NULL)
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)) {
if (addnodes == pnodes) {
sk_X509_POLICY_NODE_free(*pnodes);
*pnodes = NULL;
}
return TREE_CALC_FAILURE;
}
}
}
if (addnodes == pnodes)
return TREE_CALC_OK_DOFREE;
*pnodes = tree->auth_policies;
return TREE_CALC_OK_NOFREE;
}
/*
* Return value: 1 on success, 0 otherwise.
*/
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 == NULL)
return 0;
extra->qualifier_set = anyPolicy->data->qualifier_set;
extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS
| POLICY_DATA_FLAG_EXTRA_NODE;
node = level_add_node(NULL, extra, anyPolicy->parent, tree);
}
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;
}
/*-
* Return value: <= 0 error, otherwise one of:
* X509_PCY_TREE_VALID: valid tree
* X509_PCY_TREE_EMPTY: empty tree
* (see tree_prune()).
*/
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 X509_PCY_TREE_INTERNAL;
if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)
&& !tree_link_any(curr, cache, tree))
return X509_PCY_TREE_INTERNAL;
#ifdef OPENSSL_POLICY_DEBUG
tree_print("before tree_prune()", tree, curr);
#endif
ret = tree_prune(tree, curr);
if (ret != X509_PCY_TREE_VALID)
return ret;
}
return X509_PCY_TREE_VALID;
}
static void exnode_free(X509_POLICY_NODE *node)
{
if (node->data && (node->data->flags & POLICY_DATA_FLAG_EXTRA_NODE))
OPENSSL_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);
sk_X509_POLICY_NODE_pop_free(curr->nodes, policy_node_free);
policy_node_free(curr->anyPolicy);
}
sk_X509_POLICY_DATA_pop_free(tree->extra_data, policy_data_free);
OPENSSL_free(tree->levels);
OPENSSL_free(tree);
}
/*-
* Application policy checking function.
* Return codes:
* X509_PCY_TREE_FAILURE: Failure to satisfy explicit policy
* X509_PCY_TREE_INVALID: Inconsistent or invalid extensions
* X509_PCY_TREE_INTERNAL: Internal error, most likely malloc
* X509_PCY_TREE_VALID: Success (null tree if empty or bare TA)
*/
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 init_ret;
int ret;
int calc_ret;
X509_POLICY_TREE *tree = NULL;
STACK_OF(X509_POLICY_NODE) *nodes, *auth_nodes = NULL;
*ptree = NULL;
*pexplicit_policy = 0;
init_ret = tree_init(&tree, certs, flags);
if (init_ret <= 0)
return init_ret;
if ((init_ret & X509_PCY_TREE_EXPLICIT) == 0) {
if (init_ret & X509_PCY_TREE_EMPTY) {
X509_policy_tree_free(tree);
return X509_PCY_TREE_VALID;
}
} else {
*pexplicit_policy = 1;
/* Tree empty and requireExplicit True: Error */
if (init_ret & X509_PCY_TREE_EMPTY)
return X509_PCY_TREE_FAILURE;
}
ret = tree_evaluate(tree);
#ifdef OPENSSL_POLICY_DEBUG
tree_print("tree_evaluate()", tree, NULL);
#endif
if (ret <= 0)
goto error;
if (ret == X509_PCY_TREE_EMPTY) {
X509_policy_tree_free(tree);
if (init_ret & X509_PCY_TREE_EXPLICIT)
return X509_PCY_TREE_FAILURE;
return X509_PCY_TREE_VALID;
}
/* Tree is not empty: continue */
if ((calc_ret = tree_calculate_authority_set(tree, &auth_nodes)) == 0)
goto error;
ret = tree_calculate_user_set(tree, policy_oids, auth_nodes);
if (calc_ret == TREE_CALC_OK_DOFREE)
sk_X509_POLICY_NODE_free(auth_nodes);
if (!ret)
goto error;
*ptree = tree;
if (init_ret & X509_PCY_TREE_EXPLICIT) {
nodes = X509_policy_tree_get0_user_policies(tree);
if (sk_X509_POLICY_NODE_num(nodes) <= 0)
return X509_PCY_TREE_FAILURE;
}
return X509_PCY_TREE_VALID;
error:
X509_policy_tree_free(tree);
return X509_PCY_TREE_INTERNAL;
}
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