--- /dev/null
+From 959c59c7a0164117e7f8366466a32bb1f8d77ff1 Mon Sep 17 00:00:00 2001
+From: Pauli <pauli@openssl.org>
+Date: Wed, 8 Mar 2023 15:28:20 +1100
+Subject: [PATCH] x509: excessive resource use verifying policy constraints
+
+A security vulnerability has been identified in all supported versions
+of OpenSSL related to the verification of X.509 certificate chains
+that include policy constraints. Attackers may be able to exploit this
+vulnerability by creating a malicious certificate chain that triggers
+exponential use of computational resources, leading to a denial-of-service
+(DoS) attack on affected systems.
+
+Fixes CVE-2023-0464
+
+Reviewed-by: Tomas Mraz <tomas@openssl.org>
+Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
+(Merged from https://github.com/openssl/openssl/pull/20568)
+
+--- a/crypto/x509/pcy_local.h
++++ b/crypto/x509/pcy_local.h
+@@ -111,6 +111,11 @@ struct X509_POLICY_LEVEL_st {
+ };
+
+ struct X509_POLICY_TREE_st {
++ /* The number of nodes in the tree */
++ size_t node_count;
++ /* The maximum number of nodes in the tree */
++ size_t node_maximum;
++
+ /* This is the tree 'level' data */
+ X509_POLICY_LEVEL *levels;
+ int nlevel;
+@@ -157,7 +162,8 @@ X509_POLICY_NODE *ossl_policy_tree_find_
+ X509_POLICY_NODE *ossl_policy_level_add_node(X509_POLICY_LEVEL *level,
+ X509_POLICY_DATA *data,
+ X509_POLICY_NODE *parent,
+- X509_POLICY_TREE *tree);
++ X509_POLICY_TREE *tree,
++ int extra_data);
+ void ossl_policy_node_free(X509_POLICY_NODE *node);
+ int ossl_policy_node_match(const X509_POLICY_LEVEL *lvl,
+ const X509_POLICY_NODE *node, const ASN1_OBJECT *oid);
+--- a/crypto/x509/pcy_node.c
++++ b/crypto/x509/pcy_node.c
+@@ -59,10 +59,15 @@ X509_POLICY_NODE *ossl_policy_level_find
+ X509_POLICY_NODE *ossl_policy_level_add_node(X509_POLICY_LEVEL *level,
+ X509_POLICY_DATA *data,
+ X509_POLICY_NODE *parent,
+- X509_POLICY_TREE *tree)
++ X509_POLICY_TREE *tree,
++ int extra_data)
+ {
+ X509_POLICY_NODE *node;
+
++ /* Verify that the tree isn't too large. This mitigates CVE-2023-0464 */
++ if (tree->node_maximum > 0 && tree->node_count >= tree->node_maximum)
++ return NULL;
++
+ node = OPENSSL_zalloc(sizeof(*node));
+ if (node == NULL) {
+ ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
+@@ -70,7 +75,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
+ }
+ node->data = data;
+ node->parent = parent;
+- if (level) {
++ if (level != NULL) {
+ if (OBJ_obj2nid(data->valid_policy) == NID_any_policy) {
+ if (level->anyPolicy)
+ goto node_error;
+@@ -90,7 +95,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
+ }
+ }
+
+- if (tree) {
++ if (extra_data) {
+ if (tree->extra_data == NULL)
+ tree->extra_data = sk_X509_POLICY_DATA_new_null();
+ if (tree->extra_data == NULL){
+@@ -103,6 +108,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
+ }
+ }
+
++ tree->node_count++;
+ if (parent)
+ parent->nchild++;
+
+--- a/crypto/x509/pcy_tree.c
++++ b/crypto/x509/pcy_tree.c
+@@ -14,6 +14,17 @@
+
+ #include "pcy_local.h"
+
++/*
++ * If the maximum number of nodes in the policy tree isn't defined, set it to
++ * a generous default of 1000 nodes.
++ *
++ * Defining this to be zero means unlimited policy tree growth which opens the
++ * door on CVE-2023-0464.
++ */
++#ifndef OPENSSL_POLICY_TREE_NODES_MAX
++# define OPENSSL_POLICY_TREE_NODES_MAX 1000
++#endif
++
+ static void expected_print(BIO *channel,
+ X509_POLICY_LEVEL *lev, X509_POLICY_NODE *node,
+ int indent)
+@@ -163,6 +174,9 @@ static int tree_init(X509_POLICY_TREE **
+ return X509_PCY_TREE_INTERNAL;
+ }
+
++ /* Limit the growth of the tree to mitigate CVE-2023-0464 */
++ tree->node_maximum = OPENSSL_POLICY_TREE_NODES_MAX;
++
+ /*
+ * http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.
+ *
+@@ -180,7 +194,7 @@ static int tree_init(X509_POLICY_TREE **
+ if ((data = ossl_policy_data_new(NULL,
+ OBJ_nid2obj(NID_any_policy), 0)) == NULL)
+ goto bad_tree;
+- if (ossl_policy_level_add_node(level, data, NULL, tree) == NULL) {
++ if (ossl_policy_level_add_node(level, data, NULL, tree, 1) == NULL) {
+ ossl_policy_data_free(data);
+ goto bad_tree;
+ }
+@@ -239,7 +253,8 @@ static int tree_init(X509_POLICY_TREE **
+ * Return value: 1 on success, 0 otherwise
+ */
+ static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
+- X509_POLICY_DATA *data)
++ X509_POLICY_DATA *data,
++ X509_POLICY_TREE *tree)
+ {
+ X509_POLICY_LEVEL *last = curr - 1;
+ int i, matched = 0;
+@@ -249,13 +264,13 @@ static int tree_link_matching_nodes(X509
+ X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(last->nodes, i);
+
+ if (ossl_policy_node_match(last, node, data->valid_policy)) {
+- if (ossl_policy_level_add_node(curr, data, node, NULL) == NULL)
++ if (ossl_policy_level_add_node(curr, data, node, tree, 0) == NULL)
+ return 0;
+ matched = 1;
+ }
+ }
+ if (!matched && last->anyPolicy) {
+- if (ossl_policy_level_add_node(curr, data, last->anyPolicy, NULL) == NULL)
++ if (ossl_policy_level_add_node(curr, data, last->anyPolicy, tree, 0) == NULL)
+ return 0;
+ }
+ return 1;
+@@ -268,7 +283,8 @@ static int tree_link_matching_nodes(X509
+ * Return value: 1 on success, 0 otherwise.
+ */
+ static int tree_link_nodes(X509_POLICY_LEVEL *curr,
+- const X509_POLICY_CACHE *cache)
++ const X509_POLICY_CACHE *cache,
++ X509_POLICY_TREE *tree)
+ {
+ int i;
+
+@@ -276,7 +292,7 @@ static int tree_link_nodes(X509_POLICY_L
+ 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))
++ if (!tree_link_matching_nodes(curr, data, tree))
+ return 0;
+ }
+ return 1;
+@@ -307,7 +323,7 @@ static int tree_add_unmatched(X509_POLIC
+ /* Curr may not have anyPolicy */
+ data->qualifier_set = cache->anyPolicy->qualifier_set;
+ data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;
+- if (ossl_policy_level_add_node(curr, data, node, tree) == NULL) {
++ if (ossl_policy_level_add_node(curr, data, node, tree, 1) == NULL) {
+ ossl_policy_data_free(data);
+ return 0;
+ }
+@@ -370,7 +386,7 @@ static int tree_link_any(X509_POLICY_LEV
+ /* Finally add link to anyPolicy */
+ if (last->anyPolicy &&
+ ossl_policy_level_add_node(curr, cache->anyPolicy,
+- last->anyPolicy, NULL) == NULL)
++ last->anyPolicy, tree, 0) == NULL)
+ return 0;
+ return 1;
+ }
+@@ -553,7 +569,7 @@ static int tree_calculate_user_set(X509_
+ extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS
+ | POLICY_DATA_FLAG_EXTRA_NODE;
+ node = ossl_policy_level_add_node(NULL, extra, anyPolicy->parent,
+- tree);
++ tree, 1);
+ }
+ if (!tree->user_policies) {
+ tree->user_policies = sk_X509_POLICY_NODE_new_null();
+@@ -580,7 +596,7 @@ static int tree_evaluate(X509_POLICY_TRE
+
+ for (i = 1; i < tree->nlevel; i++, curr++) {
+ cache = ossl_policy_cache_set(curr->cert);
+- if (!tree_link_nodes(curr, cache))
++ if (!tree_link_nodes(curr, cache, tree))
+ return X509_PCY_TREE_INTERNAL;
+
+ if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)
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