Implement Metadata-Based OTA Release Compatibility Checking System

pio-scripts/build_ui.py

@@ -1,5 +1,6 @@
 Import("env")
 import shutil
+import os
 
 node_ex = shutil.which("node")
 # Check if Node.js is installed and present in PATH if it failed, abort the build
@@ -12,6 +13,24 @@
     print('\x1b[6;33;42m' + 'Installing node packages' + '\x1b[0m')
     env.Execute("npm ci")
 
+    # Extract the release name from build flags
+    release_name = None  # Let cdata.js provide the default if not found
+    build_flags = env.get("BUILD_FLAGS", [])
+    for flag in build_flags:
+        if 'WLED_RELEASE_NAME=' in flag:
+            # Extract the release name, remove quotes and handle different formats
+            parts = flag.split('WLED_RELEASE_NAME=')
+            if len(parts) > 1:
+                release_name = parts[1].split()[0].strip('\"\\')
+                break
+
+    # Set environment variable for cdata.js to use (only if found)
+    if release_name:
+        os.environ['WLED_RELEASE_NAME'] = release_name
+        print(f'Building web UI with release name: {release_name}')
+    else:
+        print('Building web UI with default release name (from cdata.js)')
+
     # Call the bundling script
     exitCode = env.Execute("npm run build")
 

tools/cdata.js

@@ -95,6 +95,11 @@ function adoptVersionAndRepo(html) {
   if (version) {
     html = html.replaceAll("##VERSION##", version);
   }
+
+  // Replace ##RELEASE## with the actual release name from build environment
+  const releaseName = process.env.WLED_RELEASE_NAME || 'Custom';
+  html = html.replaceAll("##RELEASE##", releaseName);
+
   return html;
 }
 

wled00/data/update.htm

@@ -28,10 +28,13 @@
 	<h2>WLED Software Update</h2>
 	<form method='POST' action='./update' id='upd' enctype='multipart/form-data' onsubmit="toggle('upd')">
 		Installed version: <span class="sip">WLED ##VERSION##</span><br>
+		Release: <span class="sip">##RELEASE##</span><br>
 		Download the latest binary: <a href="https://github.com/wled-dev/WLED/releases" target="_blank" 
 		style="vertical-align: text-bottom; display: inline-flex;">
 		<img src="https://img.shields.io/github/release/wled-dev/WLED.svg?style=flat-square"></a><br>
 		<input type='file' name='update' required><br> <!--should have accept='.bin', but it prevents file upload from android app-->
+		<input type='checkbox' name='skipValidation' id='skipValidation'>
+		<label for='skipValidation'>Ignore firmware validation</label><br>
 		<button type="submit">Update!</button><br>
 		<hr class="sml">
 		<button id="rev" type="button" onclick="cR()">Revert update</button><br>

wled00/ota_release_check.cpp

@@ -0,0 +1,115 @@
+#include "ota_release_check.h"
+#include "wled.h"
+
+#ifdef ESP32
+#include <esp_app_format.h>
+#include <esp_ota_ops.h>
+#endif
+
+bool extractWledCustomDesc(const uint8_t* binaryData, size_t dataSize, wled_custom_desc_t* extractedDesc) {
+    if (!binaryData || !extractedDesc || dataSize < 64) {
+        return false;
+    }
+
+    // Search in first 8KB only. This range was chosen because:
+    // - ESP32 .rodata.wled_desc sections appear early in the binary (typically within first 2-4KB)
+    // - ESP8266 .ver_number sections also appear early (typically within first 1-2KB)
+    // - 8KB provides ample coverage for metadata discovery while minimizing processing time
+    // - Larger firmware files (>1MB) would take significantly longer to process with full search
+    // - Real-world testing shows all valid metadata appears well within this range
+    const size_t search_limit = min(dataSize, (size_t)8192);
+
+    for (size_t offset = 0; offset <= search_limit - sizeof(wled_custom_desc_t); offset++) {
+        const wled_custom_desc_t* custom_desc = (const wled_custom_desc_t*)(binaryData + offset);
+
+        // Check for magic number
+        if (custom_desc->magic == WLED_CUSTOM_DESC_MAGIC) {
+            // Found potential match, validate version
+            if (custom_desc->version != WLED_CUSTOM_DESC_VERSION) {
+                DEBUG_PRINTF_P(PSTR("Found WLED structure at offset %u but version mismatch: %u\n"), 
+                              offset, custom_desc->version);
+                continue;
+            }
+
+            // Validate hash using runtime function
+            uint32_t expected_hash = djb2_hash_runtime(custom_desc->release_name);
+            if (custom_desc->crc32 != expected_hash) {
+                DEBUG_PRINTF_P(PSTR("Found WLED structure at offset %u but hash mismatch\n"), offset);
+                continue;
+            }
+
+            // Valid structure found - copy entire structure
+            memcpy(extractedDesc, custom_desc, sizeof(wled_custom_desc_t));
+
+            #ifdef ESP32
+            DEBUG_PRINTF_P(PSTR("Extracted ESP32 WLED structure from .rodata.wled_desc section at offset %u: '%s'\n"), 
+                          offset, extractedDesc->release_name);
+            #else
+            DEBUG_PRINTF_P(PSTR("Extracted ESP8266 WLED structure from .ver_number section at offset %u: '%s'\n"), 
+                          offset, extractedDesc->release_name);
+            #endif
+            return true;
+        }
+    }
+
+    DEBUG_PRINTLN(F("No WLED custom description found in binary"));
+    return false;
+}
+
+bool validateReleaseCompatibility(const char* extractedRelease) {
+  if (!extractedRelease || strlen(extractedRelease) == 0) {
+    return false;
+  }
+
+  // Simple string comparison - releases must match exactly
+  bool match = strcmp(releaseString, extractedRelease) == 0;
+
+  DEBUG_PRINTF_P(PSTR("Release compatibility check: current='%s', uploaded='%s', match=%s\n"), 
+                 releaseString, extractedRelease, match ? "YES" : "NO");
+
+  return match;
+}
+
+bool shouldAllowOTA(const uint8_t* binaryData, size_t dataSize, bool skipValidation, char* errorMessage) {
+  // Clear error message
+  if (errorMessage) {
+    errorMessage[0] = '\0';
+  }
+
+  // Ensure our custom description structure is referenced (prevents optimization)
+  const wled_custom_desc_t* local_desc = getWledCustomDesc();
+  (void)local_desc; // Suppress unused variable warning
+
+  // If user chose to skip validation, allow OTA immediately
+  if (skipValidation) {
+    DEBUG_PRINTLN(F("OTA release check bypassed by user"));
+    return true;
+  }
+
+  // Try to extract WLED structure directly from binary data
+  wled_custom_desc_t extractedDesc;
+  bool hasCustomDesc = extractWledCustomDesc(binaryData, dataSize, &extractedDesc);
+
+  if (!hasCustomDesc) {
+    // No custom description - this could be a legacy binary
+    if (errorMessage) {
+      strcpy(errorMessage, "This firmware file is missing compatibility metadata. Enable 'Ignore firmware validation' to proceed anyway.");
+    }
+    DEBUG_PRINTLN(F("OTA declined: No custom description found"));
+    return false;
+  }
+
+  // Validate compatibility using extracted release name
+  if (!validateReleaseCompatibility(extractedDesc.release_name)) {
+    if (errorMessage) {
+      snprintf(errorMessage, 127, "Firmware compatibility mismatch: current='%s', uploaded='%s'. Enable 'Ignore firmware validation' to proceed anyway.", 
+               releaseString, extractedDesc.release_name);
+    }
+    DEBUG_PRINTF_P(PSTR("OTA declined: Release mismatch current='%s', uploaded='%s'\n"), 
+                   releaseString, extractedDesc.release_name);
+    return false;
+  }
+
+  DEBUG_PRINTLN(F("OTA allowed: Release names match"));
+  return true;
+}

wled00/ota_release_check.h

@@ -0,0 +1,83 @@
+#ifndef WLED_OTA_RELEASE_CHECK_H
+#define WLED_OTA_RELEASE_CHECK_H
+
+/*
+ * OTA Release Compatibility Checking using ESP-IDF Custom Description Section
+ * Functions to extract and validate release names from uploaded binary files using embedded metadata
+ */
+
+#include <Arduino.h>
+
+#ifdef ESP32
+#include <esp_app_format.h>
+#endif
+
+#define WLED_CUSTOM_DESC_MAGIC 0x57535453  // "WSTS" (WLED System Tag Structure)
+#define WLED_CUSTOM_DESC_VERSION 1
+#define WLED_RELEASE_NAME_MAX_LEN 48
+
+/**
+ * DJB2 hash function (C++11 compatible constexpr)
+ * Used for compile-time hash computation of release names
+ */
+constexpr uint32_t djb2_hash_constexpr(const char* str, uint32_t hash = 5381) {
+    return (*str == '\0') ? hash : djb2_hash_constexpr(str + 1, ((hash << 5) + hash) + *str);
+}
+
+/**
+ * Runtime DJB2 hash function for validation
+ */
+inline uint32_t djb2_hash_runtime(const char* str) {
+    uint32_t hash = 5381;
+    while (*str) {
+        hash = ((hash << 5) + hash) + *str++;
+    }
+    return hash;
+}
+
+/**
+ * WLED Custom Description Structure
+ * This structure is embedded in platform-specific sections at a fixed offset
+ * in ESP32/ESP8266 binaries, allowing extraction without modifying the binary format
+ */
+typedef struct {
+    uint32_t magic;               // Magic number to identify WLED custom description
+    uint32_t version;             // Structure version for future compatibility
+    char release_name[WLED_RELEASE_NAME_MAX_LEN]; // Release name (null-terminated)
+    uint32_t crc32;              // CRC32 of the above fields for integrity check
+} __attribute__((packed)) wled_custom_desc_t;
+
+/**
+ * Extract WLED custom description structure from binary
+ * @param binaryData Pointer to binary file data
+ * @param dataSize Size of binary data in bytes
+ * @param extractedDesc Buffer to store extracted custom description structure
+ * @return true if structure was found and extracted, false otherwise
+ */
+bool extractWledCustomDesc(const uint8_t* binaryData, size_t dataSize, wled_custom_desc_t* extractedDesc);
+
+/**
+ * Validate if extracted release name matches current release
+ * @param extractedRelease Release name from uploaded binary
+ * @return true if releases match (OTA should proceed), false if they don't match
+ */
+bool validateReleaseCompatibility(const char* extractedRelease);
+
+/**
+ * Check if OTA should be allowed based on release compatibility using custom description
+ * @param binaryData Pointer to binary file data (not modified)
+ * @param dataSize Size of binary data in bytes
+ * @param skipValidation If true, skip release validation
+ * @param errorMessage Buffer to store error message if validation fails (should be at least 128 bytes)
+ * @return true if OTA should proceed, false if it should be blocked
+ */
+bool shouldAllowOTA(const uint8_t* binaryData, size_t dataSize, bool skipValidation, char* errorMessage);
+
+/**
+ * Get pointer to the embedded custom description structure
+ * This ensures the structure is referenced and not optimized out
+ * @return pointer to the custom description structure
+ */
+const wled_custom_desc_t* getWledCustomDesc();
+
+#endif // WLED_OTA_RELEASE_CHECK_H

wled00/wled_custom_desc.cpp

@@ -0,0 +1,25 @@
+#include "ota_release_check.h"
+#include "wled.h"
+
+// Platform-specific section definition
+#ifdef ESP32
+#define WLED_CUSTOM_DESC_SECTION ".rodata.wled_desc"
+#elif defined(ESP8266)
+#define WLED_CUSTOM_DESC_SECTION ".ver_number"
+#endif
+
+// Single structure definition for both platforms
+const wled_custom_desc_t __attribute__((section(WLED_CUSTOM_DESC_SECTION))) wled_custom_description = {
+    WLED_CUSTOM_DESC_MAGIC,                   // magic
+    WLED_CUSTOM_DESC_VERSION,                 // version  
+    WLED_RELEASE_NAME,                        // release_name
+    djb2_hash_constexpr(WLED_RELEASE_NAME)   // crc32 - computed at compile time
+};
+
+// Single reference to ensure it's not optimized away
+const wled_custom_desc_t* __attribute__((used)) wled_custom_desc_ref = &wled_custom_description;
+
+// Function to ensure the structure is referenced by code
+const wled_custom_desc_t* getWledCustomDesc() {
+    return &wled_custom_description;
+}

wled00/wled_server.cpp

@@ -6,6 +6,7 @@
   #else
     #include <Update.h>
   #endif
+  #include "ota_release_check.h"
 #endif
 #include "html_ui.h"
 #include "html_settings.h"
@@ -424,32 +425,87 @@ void initServer()
       return;
     }
     if (!correctPIN || otaLock) return;
+
+    // Static variable to track release check status across chunks
+    static bool releaseCheckPassed = false;
+
     if(!index){
       DEBUG_PRINTLN(F("OTA Update Start"));
+
+      // Check if user wants to skip validation
+      bool skipValidation = request->hasParam("skipValidation", true);
+
+      // If user chose to skip validation, proceed without compatibility check
+      if (skipValidation) {
+        DEBUG_PRINTLN(F("OTA validation skipped by user"));
+        releaseCheckPassed = true;
+      } else {
+        // Validate OTA release compatibility using the first chunk data directly
+        char errorMessage[128];
+        releaseCheckPassed = shouldAllowOTA(data, len, false, errorMessage);
+
+        if (!releaseCheckPassed) {
+          DEBUG_PRINTF_P(PSTR("OTA declined: %s\n"), errorMessage);
+          request->send(400, FPSTR(CONTENT_TYPE_PLAIN), errorMessage);
+          return;
+        }
+      }
+
+      DEBUG_PRINTLN(F("Release check passed, starting OTA update"));
+
       #if WLED_WATCHDOG_TIMEOUT > 0
       WLED::instance().disableWatchdog();
       #endif
       UsermodManager::onUpdateBegin(true); // notify usermods that update is about to begin (some may require task de-init)
       lastEditTime = millis(); // make sure PIN does not lock during update
+
+      // Start the actual OTA update
       strip.suspend();
       backupConfig(); // backup current config in case the update ends badly
       strip.resetSegments();  // free as much memory as you can
       #ifdef ESP8266
       Update.runAsync(true);
       #endif
-      Update.begin((ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000);
-    }
-    if(!Update.hasError()) Update.write(data, len);
-    if(isFinal){
-      if(Update.end(true)){
-        DEBUG_PRINTLN(F("Update Success"));
-      } else {
-        DEBUG_PRINTLN(F("Update Failed"));
+
+      // Begin update with the firmware size from content length
+      size_t updateSize = request->contentLength() > 0 ? request->contentLength() : ((ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000);
+      if (!Update.begin(updateSize)) {
+        DEBUG_PRINTF_P(PSTR("OTA Failed to begin: %s\n"), Update.getErrorString().c_str());
         strip.resume();
-        UsermodManager::onUpdateBegin(false); // notify usermods that update has failed (some may require task init)
+        UsermodManager::onUpdateBegin(false);
         #if WLED_WATCHDOG_TIMEOUT > 0
         WLED::instance().enableWatchdog();
         #endif
+        #ifdef ESP32
+        request->send(500, FPSTR(CONTENT_TYPE_PLAIN), String("Update.begin failed: ") + Update.errorString());
+        #else
+        request->send(500, FPSTR(CONTENT_TYPE_PLAIN), String("Update.begin failed: ") + Update.getErrorString());
+        #endif
+        return;
+      }
+    }
+
+    // Write chunk data to OTA update (only if release check passed)
+    if (releaseCheckPassed && !Update.hasError()) {
+      if (Update.write(data, len) != len) {
+        DEBUG_PRINTF_P(PSTR("OTA write failed on chunk %zu: %s\n"), index, Update.getErrorString().c_str());
+      }
+    }
+
+    if(isFinal){
+      DEBUG_PRINTLN(F("OTA Update End"));
+
+      if (releaseCheckPassed) {
+        if(Update.end(true)){
+          DEBUG_PRINTLN(F("Update Success"));
+        } else {
+          DEBUG_PRINTLN(F("Update Failed"));
+          strip.resume();
+          UsermodManager::onUpdateBegin(false); // notify usermods that update has failed (some may require task init)
+          #if WLED_WATCHDOG_TIMEOUT > 0
+          WLED::instance().enableWatchdog();
+          #endif
+        }
       }
     }
   });