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

   1 From 879f7080d7e141f415c79eaa3a8ac4a3dad0348b 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/20569)
  18
  19 diff --git a/crypto/x509v3/pcy_local.h b/crypto/x509v3/pcy_local.h
  20 index 5daf78de45..344aa06765 100644
  21 --- a/crypto/x509v3/pcy_local.h
  22 +++ b/crypto/x509v3/pcy_local.h
  23 @@ -111,6 +111,11 @@ struct X509_POLICY_LEVEL_st {
  24  };
  25
  26  struct X509_POLICY_TREE_st {
  27 +    /* The number of nodes in the tree */
  28 +    size_t node_count;
  29 +    /* The maximum number of nodes in the tree */
  30 +    size_t node_maximum;
  31 +
  32      /* This is the tree 'level' data */
  33      X509_POLICY_LEVEL *levels;
  34      int nlevel;
  35 @@ -159,7 +164,8 @@ X509_POLICY_NODE *tree_find_sk(STACK_OF(X509_POLICY_NODE) *sk,
  36  X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
  37                                   X509_POLICY_DATA *data,
  38                                   X509_POLICY_NODE *parent,
  39 -                                 X509_POLICY_TREE *tree);
  40 +                                 X509_POLICY_TREE *tree,
  41 +                                 int extra_data);
  42  void policy_node_free(X509_POLICY_NODE *node);
  43  int policy_node_match(const X509_POLICY_LEVEL *lvl,
  44                        const X509_POLICY_NODE *node, const ASN1_OBJECT *oid);
  45 diff --git a/crypto/x509v3/pcy_node.c b/crypto/x509v3/pcy_node.c
  46 index e2d7b15322..d574fb9d66 100644
  47 --- a/crypto/x509v3/pcy_node.c
  48 +++ b/crypto/x509v3/pcy_node.c
  49 @@ -59,10 +59,15 @@ X509_POLICY_NODE *level_find_node(const X509_POLICY_LEVEL *level,
  50  X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
  51                                   X509_POLICY_DATA *data,
  52                                   X509_POLICY_NODE *parent,
  53 -                                 X509_POLICY_TREE *tree)
  54 +                                 X509_POLICY_TREE *tree,
  55 +                                 int extra_data)
  56  {
  57      X509_POLICY_NODE *node;
  58
  59 +    /* Verify that the tree isn't too large.  This mitigates CVE-2023-0464 */
  60 +    if (tree->node_maximum > 0 && tree->node_count >= tree->node_maximum)
  61 +        return NULL;
  62 +
  63      node = OPENSSL_zalloc(sizeof(*node));
  64      if (node == NULL) {
  65          X509V3err(X509V3_F_LEVEL_ADD_NODE, ERR_R_MALLOC_FAILURE);
  66 @@ -70,7 +75,7 @@ X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
  67      }
  68      node->data = data;
  69      node->parent = parent;
  70 -    if (level) {
  71 +    if (level != NULL) {
  72          if (OBJ_obj2nid(data->valid_policy) == NID_any_policy) {
  73              if (level->anyPolicy)
  74                  goto node_error;
  75 @@ -90,7 +95,7 @@ X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
  76          }
  77      }
  78
  79 -    if (tree) {
  80 +    if (extra_data) {
  81          if (tree->extra_data == NULL)
  82              tree->extra_data = sk_X509_POLICY_DATA_new_null();
  83          if (tree->extra_data == NULL){
  84 @@ -103,6 +108,7 @@ X509_POLICY_NODE *level_add_node(X509_POLICY_LEVEL *level,
  85          }
  86      }
  87
  88 +    tree->node_count++;
  89      if (parent)
  90          parent->nchild++;
  91
  92 diff --git a/crypto/x509v3/pcy_tree.c b/crypto/x509v3/pcy_tree.c
  93 index 6e8322cbc5..6c7fd35405 100644
  94 --- a/crypto/x509v3/pcy_tree.c
  95 +++ b/crypto/x509v3/pcy_tree.c
  96 @@ -13,6 +13,18 @@
  97
  98  #include "pcy_local.h"
  99
 100 +/*
 101 + * If the maximum number of nodes in the policy tree isn't defined, set it to
 102 + * a generous default of 1000 nodes.
 103 + *
 104 + * Defining this to be zero means unlimited policy tree growth which opens the
 105 + * door on CVE-2023-0464.
 106 + */
 107 +
 108 +#ifndef OPENSSL_POLICY_TREE_NODES_MAX
 109 +# define OPENSSL_POLICY_TREE_NODES_MAX 1000
 110 +#endif
 111 +
 112  /*
 113   * Enable this to print out the complete policy tree at various point during
 114   * evaluation.
 115 @@ -168,6 +180,9 @@ static int tree_init(X509_POLICY_TREE **ptree, STACK_OF(X509) *certs,
 116          return X509_PCY_TREE_INTERNAL;
 117      }
 118
 119 +    /* Limit the growth of the tree to mitigate CVE-2023-0464 */
 120 +    tree->node_maximum = OPENSSL_POLICY_TREE_NODES_MAX;
 121 +
 122      /*
 123       * http://tools.ietf.org/html/rfc5280#section-6.1.2, figure 3.
 124       *
 125 @@ -184,7 +199,7 @@ static int tree_init(X509_POLICY_TREE **ptree, STACK_OF(X509) *certs,
 126      level = tree->levels;
 127      if ((data = policy_data_new(NULL, OBJ_nid2obj(NID_any_policy), 0)) == NULL)
 128          goto bad_tree;
 129 -    if (level_add_node(level, data, NULL, tree) == NULL) {
 130 +    if (level_add_node(level, data, NULL, tree, 1) == NULL) {
 131          policy_data_free(data);
 132          goto bad_tree;
 133      }
 134 @@ -243,7 +258,8 @@ static int tree_init(X509_POLICY_TREE **ptree, STACK_OF(X509) *certs,
 135   * Return value: 1 on success, 0 otherwise
 136   */
 137  static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
 138 -                                    X509_POLICY_DATA *data)
 139 +                                    X509_POLICY_DATA *data,
 140 +                                    X509_POLICY_TREE *tree)
 141  {
 142      X509_POLICY_LEVEL *last = curr - 1;
 143      int i, matched = 0;
 144 @@ -253,13 +269,13 @@ static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
 145          X509_POLICY_NODE *node = sk_X509_POLICY_NODE_value(last->nodes, i);
 146
 147          if (policy_node_match(last, node, data->valid_policy)) {
 148 -            if (level_add_node(curr, data, node, NULL) == NULL)
 149 +            if (level_add_node(curr, data, node, tree, 0) == NULL)
 150                  return 0;
 151              matched = 1;
 152          }
 153      }
 154      if (!matched && last->anyPolicy) {
 155 -        if (level_add_node(curr, data, last->anyPolicy, NULL) == NULL)
 156 +        if (level_add_node(curr, data, last->anyPolicy, tree, 0) == NULL)
 157              return 0;
 158      }
 159      return 1;
 160 @@ -272,7 +288,8 @@ static int tree_link_matching_nodes(X509_POLICY_LEVEL *curr,
 161   * Return value: 1 on success, 0 otherwise.
 162   */
 163  static int tree_link_nodes(X509_POLICY_LEVEL *curr,
 164 -                           const X509_POLICY_CACHE *cache)
 165 +                           const X509_POLICY_CACHE *cache,
 166 +                           X509_POLICY_TREE *tree)
 167  {
 168      int i;
 169
 170 @@ -280,7 +297,7 @@ static int tree_link_nodes(X509_POLICY_LEVEL *curr,
 171          X509_POLICY_DATA *data = sk_X509_POLICY_DATA_value(cache->data, i);
 172
 173          /* Look for matching nodes in previous level */
 174 -        if (!tree_link_matching_nodes(curr, data))
 175 +        if (!tree_link_matching_nodes(curr, data, tree))
 176              return 0;
 177      }
 178      return 1;
 179 @@ -311,7 +328,7 @@ static int tree_add_unmatched(X509_POLICY_LEVEL *curr,
 180      /* Curr may not have anyPolicy */
 181      data->qualifier_set = cache->anyPolicy->qualifier_set;
 182      data->flags |= POLICY_DATA_FLAG_SHARED_QUALIFIERS;
 183 -    if (level_add_node(curr, data, node, tree) == NULL) {
 184 +    if (level_add_node(curr, data, node, tree, 1) == NULL) {
 185          policy_data_free(data);
 186          return 0;
 187      }
 188 @@ -373,7 +390,7 @@ static int tree_link_any(X509_POLICY_LEVEL *curr,
 189      }
 190      /* Finally add link to anyPolicy */
 191      if (last->anyPolicy &&
 192 -        level_add_node(curr, cache->anyPolicy, last->anyPolicy, NULL) == NULL)
 193 +        level_add_node(curr, cache->anyPolicy, last->anyPolicy, tree, 0) == NULL)
 194          return 0;
 195      return 1;
 196  }
 197 @@ -555,7 +572,7 @@ static int tree_calculate_user_set(X509_POLICY_TREE *tree,
 198              extra->qualifier_set = anyPolicy->data->qualifier_set;
 199              extra->flags = POLICY_DATA_FLAG_SHARED_QUALIFIERS
 200                  | POLICY_DATA_FLAG_EXTRA_NODE;
 201 -            node = level_add_node(NULL, extra, anyPolicy->parent, tree);
 202 +            node = level_add_node(NULL, extra, anyPolicy->parent, tree, 1);
 203          }
 204          if (!tree->user_policies) {
 205              tree->user_policies = sk_X509_POLICY_NODE_new_null();
 206 @@ -582,7 +599,7 @@ static int tree_evaluate(X509_POLICY_TREE *tree)
 207
 208      for (i = 1; i < tree->nlevel; i++, curr++) {
 209          cache = policy_cache_set(curr->cert);
 210 -        if (!tree_link_nodes(curr, cache))
 211 +        if (!tree_link_nodes(curr, cache, tree))
 212              return X509_PCY_TREE_INTERNAL;
 213
 214          if (!(curr->flags & X509_V_FLAG_INHIBIT_ANY)