Fix several possible double free() in ESP32 network_driver.c

Removes several possible uses of free() on memory that had been previously free'd. This would
happen under specific error conditions in the `start_network` function in network_driver.c
that `network:start/1` uses to configure and start the network.

Signed-off-by: Winford <winford@object.stream>

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.3] - Unreleased
+
+### Fixed
+- Fix several uses of free on prevously released memory on ESP32, under certain error condition using
+`network:start/1`, that would lead to a hard crash of the VM.
+
 ## [0.6.2] - 25-05-2024
 
 ### Added

src/platforms/esp32/components/avm_builtins/network_driver.c

@@ -723,7 +723,6 @@ static void start_network(Context *ctx, term pid, term ref, term config)
         if ((err = esp_wifi_set_config(ESP_IF_WIFI_AP, ap_wifi_config)) != ESP_OK) {
             ESP_LOGE(TAG, "Error setting AP mode config %d", err);
             free(ap_wifi_config);
-            free(sta_wifi_config);
             term error = port_create_error_tuple(ctx, term_from_int(err));
             port_send_reply(ctx, pid, ref, error);
             return;
@@ -732,12 +731,14 @@ static void start_network(Context *ctx, term pid, term ref, term config)
             free(ap_wifi_config);
         }
     }
+
+    //
+    // Start the configured interface(s)
+    //
     if ((err = esp_wifi_start()) != ESP_OK) {
         ESP_LOGE(TAG, "Error in esp_wifi_start %d", err);
         term error = port_create_error_tuple(ctx, term_from_int(err));
         port_send_reply(ctx, pid, ref, error);
-        free(ap_wifi_config);
-        free(sta_wifi_config);
         return;
     } else {
         ESP_LOGI(TAG, "WIFI started");