firmware-ota (#2)

Reviewed-on: #2

Provider/main/api/ota/frontend.cpp

@@ -8,7 +8,6 @@
 #include "nvs.h"
 #include "nvs_flash.h"
 
-
 // Project
 #include "appstate.hpp"
 #include "types.hpp"
@@ -59,6 +58,7 @@ internal esp_err_t api_ota_frontend_handler(httpd_req_t *req)
 
   int total_read = 0;
   int remaining = req->content_len;
+  bool first_chunk = true;
 
   while (remaining > 0)
   {
@@ -77,6 +77,21 @@ internal esp_err_t api_ota_frontend_handler(httpd_req_t *req)
       return ESP_FAIL;
     }
 
+    if (first_chunk)
+    {
+      if ((uint8_t)buf[0] == 0xE9)
+      {
+        ESP_LOGE("OTA", "Magic 0xE9 detected. This looks like a FIRMWARE bin, "
+                        "but you are uploading to FRONTEND slot!");
+        free(buf);
+        httpd_resp_send_err(
+            req, HTTPD_400_BAD_REQUEST,
+            "Invalid file: This is a Firmware binary, not a UI binary.");
+        return ESP_FAIL;
+      }
+      first_chunk = false;
+    }
+
     err = esp_partition_write(partition, total_read, buf, recv_len);
     if (err != ESP_OK)
     {