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 https://github.com/openssl/openssl/pull/21066)

1 files changed, 15 insertions, 4 deletions

diff --git a/crypto/x509v3/pcy_tree.c b/crypto/x509v3/pcy_tree.c
index 6c7fd35405..3c504e82c6 100644
--- a/crypto/x509v3/pcy_tree.c
+++ b/crypto/x509v3/pcy_tree.c
@@ -25,6 +25,8 @@
 # define OPENSSL_POLICY_TREE_NODES_MAX 1000
 #endif
 
+static void exnode_free(X509_POLICY_NODE *node);
+
 /*
  * Enable this to print out the complete policy tree at various point during
  * evaluation.
@@ -572,15 +574,24 @@ static int tree_calculate_user_set(X509_POLICY_TREE *tree,
             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, 1);
+            node = level_add_node(NULL, extra, anyPolicy->parent,
+                                  tree, 1);
+            if (node == NULL) {
+                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;
 }