package/libs/openssl/patches/200-x509-excessive-resource-use-verifying-policy-constra.patch

   1 From 959c59c7a0164117e7f8366466a32bb1f8d77ff1 Mon Sep 17 00:00:00 2001
   2 From: Pauli <pauli@openssl.org>
   3 Date: Wed, 8 Mar 2023 15:28:20 +1100
   4 Subject: [PATCH] x509: excessive resource use verifying policy constraints
   5
   6 A security vulnerability has been identified in all supported versions
   7 of OpenSSL related to the verification of X.509 certificate chains
   8 that include policy constraints.  Attackers may be able to exploit this
   9 vulnerability by creating a malicious certificate chain that triggers
  10 exponential use of computational resources, leading to a denial-of-service
  11 (DoS) attack on affected systems.
  12
  13 Fixes CVE-2023-0464
  14
  15 Reviewed-by: Tomas Mraz <tomas@openssl.org>
  16 Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
  17 (Merged from https://github.com/openssl/openssl/pull/20568)
  18
  19 --- a/crypto/x509/pcy_local.h
  20 +++ b/crypto/x509/pcy_local.h
  21 @@ -111,6 +111,11 @@ struct X509_POLICY_LEVEL_st {
  22  };
  23
  24  struct X509_POLICY_TREE_st {
  25 +    /* The number of nodes in the tree */
  26 +    size_t node_count;
  27 +    /* The maximum number of nodes in the tree */
  28 +    size_t node_maximum;
  29 +
  30      /* This is the tree 'level' data */
  31      X509_POLICY_LEVEL *levels;
  32      int nlevel;
  33 @@ -157,7 +162,8 @@ X509_POLICY_NODE *ossl_policy_tree_find_
  34  X509_POLICY_NODE *ossl_policy_level_add_node(X509_POLICY_LEVEL *level,
  35                                               X509_POLICY_DATA *data,
  36                                               X509_POLICY_NODE *parent,
  37 -                                             X509_POLICY_TREE *tree);
  38 +                                             X509_POLICY_TREE *tree,
  39 +                                             int extra_data);
  40  void ossl_policy_node_free(X509_POLICY_NODE *node);
  41  int ossl_policy_node_match(const X509_POLICY_LEVEL *lvl,
  42                             const X509_POLICY_NODE *node, const ASN1_OBJECT *oid);
  43 --- a/crypto/x509/pcy_node.c
  44 +++ b/crypto/x509/pcy_node.c
  45 @@ -59,10 +59,15 @@ X509_POLICY_NODE *ossl_policy_level_find
  46  X509_POLICY_NODE *ossl_policy_level_add_node(X509_POLICY_LEVEL *level,
  47                                               X509_POLICY_DATA *data,
  48                                               X509_POLICY_NODE *parent,
  49 -                                             X509_POLICY_TREE *tree)
  50 +                                             X509_POLICY_TREE *tree,
  51 +                                             int extra_data)
  52  {
  53      X509_POLICY_NODE *node;
  54
  55 +    /* Verify that the tree isn't too large.  This mitigates CVE-2023-0464 */
  56 +    if (tree->node_maximum > 0 && tree->node_count >= tree->node_maximum)
  57 +        return NULL;
  58 +
  59      node = OPENSSL_zalloc(sizeof(*node));
  60      if (node == NULL) {
  61          ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);
  62 @@ -70,7 +75,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
  63      }
  64      node->data = data;
  65      node->parent = parent;
  66 -    if (level) {
  67 +    if (level != NULL) {
  68          if (OBJ_obj2nid(data->valid_policy) == NID_any_policy) {
  69              if (level->anyPolicy)
  70                  goto node_error;
  71 @@ -90,7 +95,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
  72          }
  73      }
  74
  75 -    if (tree) {
  76 +    if (extra_data) {
  77          if (tree->extra_data == NULL)
  78              tree->extra_data = sk_X509_POLICY_DATA_new_null();
  79          if (tree->extra_data == NULL){
  80 @@ -103,6 +108,7 @@ X509_POLICY_NODE *ossl_policy_level_add_
  81          }
  82      }
  83
  84 +    tree->node_count++;
  85      if (parent)
  86          parent->nchild++;
  87
  88 --- a/crypto/x509/pcy_tree.c
  89 +++ b/crypto/x509/pcy_tree.c
  90 @@ -14,6 +14,17 @@
  91
  92  #include "pcy_local.h"
  93
  94 +/*
  95 + * If the maximum number of nodes in the policy tree isn't defined, set it to
  96 + * a generous default of 1000 nodes.
  97 + *
  98 + * Defining this to be zero means unlimited policy tree growth which opens the
  99 + * door on CVE-2023-0464.
 100 + */
 101 +#ifndef OPENSSL_POLICY_TREE_NODES_MAX
 102 +# define OPENSSL_POLICY_TREE_NODES_MAX 1000
 103 +#endif
 104 +
 105  static void expected_print(BIO *channel,
 106                             X509_POLICY_LEVEL *lev, X509_POLICY_NODE *node,
 107                             int indent)
 108 @@ -163,6 +174,9 @@ static int tree_init(X509_POLICY_TREE **
 109          return X509_PCY_TREE_INTERNAL;
 110      }
 111
 112 +    /* Limit the growth of the tree to mitigate CVE-2023-0464 */
 113 +    tree->node_maximum = OPENSSL_POLICY_TREE_NODES_MAX;
 114 +
 115      /*
 116       * http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.
 117       *
 118 @@ -180,7 +194,7 @@ static int tree_init(X509_POLICY_TREE **
 119      if ((data = ossl_policy_data_new(NULL,
 120                                       OBJ_nid2obj(NID_any_policy), 0)) == NULL)
 121          goto bad_tree;
 122 -    if (ossl_policy_level_add_node(level, data, NULL, tree) == NULL) {
 123 +    if (ossl_policy_level_add_node(level, data, NULL, tree, 1) == NULL) {
 124          ossl_policy_data_free(data);
 125          goto bad_tree;
 126      }
 127 @@ -239,7 +253,8 @@ static int tree_init(X509_POLICY_TREE **
 128   * Return value: 1 on success, 0 otherwise
 129   */
 130  static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
 131 -                                    X509_POLICY_DATA *data)
 132 +                                    X509_POLICY_DATA *data,
 133 +                                    X509_POLICY_TREE *tree)
 134  {
 135      X509_POLICY_LEVEL *last = curr - 1;
 136      int i, matched = 0;
 137 @@ -249,13 +264,13 @@ static int tree_link_matching_nodes(X509
 138          X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(last->nodes, i);
 139
 140          if (ossl_policy_node_match(last, node, data->valid_policy)) {
 141 -            if (ossl_policy_level_add_node(curr, data, node, NULL) == NULL)
 142 +            if (ossl_policy_level_add_node(curr, data, node, tree, 0) == NULL)
 143                  return 0;
 144              matched = 1;
 145          }
 146      }
 147      if (!matched && last->anyPolicy) {
 148 -        if (ossl_policy_level_add_node(curr, data, last->anyPolicy, NULL) == NULL)
 149 +        if (ossl_policy_level_add_node(curr, data, last->anyPolicy, tree, 0) == NULL)
 150              return 0;
 151      }
 152      return 1;
 153 @@ -268,7 +283,8 @@ static int tree_link_matching_nodes(X509
 154   * Return value: 1 on success, 0 otherwise.
 155   */
 156  static int tree_link_nodes(X509_POLICY_LEVEL *curr,
 157 -                           const X509_POLICY_CACHE *cache)
 158 +                           const X509_POLICY_CACHE *cache,
 159 +                           X509_POLICY_TREE *tree)
 160  {
 161      int i;
 162
 163 @@ -276,7 +292,7 @@ static int tree_link_nodes(X509_POLICY_L
 164          X509_POLICY_DATA *data = sk_X509_POLICY_DATA_value(cache->data, i);
 165
 166          /* Look for matching nodes in previous level */
 167 -        if (!tree_link_matching_nodes(curr, data))
 168 +        if (!tree_link_matching_nodes(curr, data, tree))
 169              return 0;
 170      }
 171      return 1;
 172 @@ -307,7 +323,7 @@ static int tree_add_unmatched(X509_POLIC
 173      /* Curr may not have anyPolicy */
 174      data->qualifier_set = cache->anyPolicy->qualifier_set;
 175      data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;
 176 -    if (ossl_policy_level_add_node(curr, data, node, tree) == NULL) {
 177 +    if (ossl_policy_level_add_node(curr, data, node, tree, 1) == NULL) {
 178          ossl_policy_data_free(data);
 179          return 0;
 180      }
 181 @@ -370,7 +386,7 @@ static int tree_link_any(X509_POLICY_LEV
 182      /* Finally add link to anyPolicy */
 183      if (last->anyPolicy &&
 184              ossl_policy_level_add_node(curr, cache->anyPolicy,
 185 -                                       last->anyPolicy, NULL) == NULL)
 186 +                                       last->anyPolicy, tree, 0) == NULL)
 187          return 0;
 188      return 1;
 189  }
 190 @@ -553,7 +569,7 @@ static int tree_calculate_user_set(X509_
 191              extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS
 192                  | POLICY_DATA_FLAG_EXTRA_NODE;
 193              node = ossl_policy_level_add_node(NULL, extra, anyPolicy->parent,
 194 -                                              tree);
 195 +                                              tree, 1);
 196          }
 197          if (!tree->user_policies) {
 198              tree->user_policies = sk_X509_POLICY_NODE_new_null();
 199 @@ -580,7 +596,7 @@ static int tree_evaluate(X509_POLICY_TRE
 200
 201      for (i = 1; i < tree->nlevel; i++, curr++) {
 202          cache = ossl_policy_cache_set(curr->cert);
 203 -        if (!tree_link_nodes(curr, cache))
 204 +        if (!tree_link_nodes(curr, cache, tree))
 205              return X509_PCY_TREE_INTERNAL;
 206
 207          if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)