Merge pull request #237 from LedgerHQ/count_keys

Refactor `count_distinct_keys_info`

Makefile

@@ -21,7 +21,19 @@ endif
 
 include $(BOLOS_SDK)/Makefile.defines
 
-# TODO: compile with the right path restrictions
+# TODO: Compile with the right path restrictions
+#
+#       The right path restriction would be something like
+#         --path "*'/0'"
+#       for mainnet, and
+#         --path "*'/1'"
+#       for testnet.
+#
+#       That is, restrict the BIP-44 coin_type, but not the purpose.
+#       However, such wildcards are not currently supported by the OS.
+#
+#       Note that the app still requires explicit user approval before exporting
+#       any xpub outside of a small set of allowed standard paths.
 
 # Application allowed derivation curves.
 CURVE_APP_LOAD_PARAMS = secp256k1

src/handler/lib/policy.c

@@ -1723,13 +1723,16 @@ int get_key_placeholder_by_index(const policy_node_t *policy,
 }
 
 int count_distinct_keys_info(const policy_node_t *policy) {
-    policy_node_key_placeholder_t placeholder;
-    int ret = -1, cur, n_placeholders;
+    int ret = -1;
 
-    for (cur = 0;
-         cur < (n_placeholders = get_key_placeholder_by_index(policy, cur, NULL, &placeholder));
-         ++cur) {
-        if (n_placeholders < 0) {
+    int n_placeholders = get_key_placeholder_by_index(policy, 0, NULL, NULL);
+    if (n_placeholders < 0) {
+        return -1;
+    }
+
+    for (int cur = 0; cur < n_placeholders; ++cur) {
+        policy_node_key_placeholder_t placeholder;
+        if (0 > get_key_placeholder_by_index(policy, cur, NULL, &placeholder)) {
             return -1;
         }
         ret = MAX(ret, placeholder.key_index + 1);