x509: Handle ossl_policy_level_add_node errors

The invocation of ossl_policy_level_add_node in tree_calculate_user_set
did not have any error handling. Add it to prevent a memory leak for the
allocated extra policy data.

Also add error handling to sk_X509_POLICY_NODE_push to ensure that if
a new node was allocated, but could not be added to the stack, it is
freed correctly.

Fix error handling if tree->user_policies cannot be allocated by
returning 0, indicating failure, rather than 1.

Signed-off-by: Clemens Lang <cllang@redhat.com>

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #21040)

(cherry picked from commit 95a8aa6)

crypto/x509/pcy_tree.c

@@ -25,6 +25,8 @@
 # define OPENSSL_POLICY_TREE_NODES_MAX 1000
 #endif
 
+static void exnode_free(X509_POLICY_NODE *node);
+
 static void expected_print(BIO *channel,
                            X509_POLICY_LEVEL *lev, X509_POLICY_NODE *node,
                            int indent)
@@ -570,14 +572,22 @@ static int tree_calculate_user_set(X509_POLICY_TREE *tree,
                 | POLICY_DATA_FLAG_EXTRA_NODE;
             node = ossl_policy_level_add_node(NULL, extra, anyPolicy->parent,
                                               tree, 1);
+            if (node == NULL) {
+                ossl_policy_data_free(extra);
+                return 0;
+            }
         }
         if (!tree->user_policies) {
             tree->user_policies = sk_X509_POLICY_NODE_new_null();
-            if (!tree->user_policies)
-                return 1;
+            if (!tree->user_policies) {
+                exnode_free(node);
+                return 0;
+            }
         }
-        if (!sk_X509_POLICY_NODE_push(tree->user_policies, node))
+        if (!sk_X509_POLICY_NODE_push(tree->user_policies, node)) {
+            exnode_free(node);
             return 0;
+        }
     }
     return 1;
 }