Fix codeQL failures

server/controllers/SearchController.js

@@ -4,7 +4,7 @@ const BookFinder = require('../finders/BookFinder')
 const PodcastFinder = require('../finders/PodcastFinder')
 const AuthorFinder = require('../finders/AuthorFinder')
 const Database = require('../Database')
-const { isValidASIN } = require('../utils')
+const { isValidASIN, getQueryParamAsString } = require('../utils')
 
 // Provider name mappings for display purposes
 const providerMap = {
@@ -139,9 +139,10 @@ class SearchController {
    * @param {Response} res
    */
   async findBooks(req, res) {
-    const provider = req.query.provider || 'google'
+    // Safely extract query parameters, rejecting arrays to prevent type confusion
-    const title = req.query.title || ''
+    const provider = getQueryParamAsString(req.query.provider, 'google')
-    const author = req.query.author || ''
+    const title = getQueryParamAsString(req.query.title, '')
+    const author = getQueryParamAsString(req.query.author, '')
 
     // Validate string parameters
     const validation = SearchController.validateStringParams({ provider, title, author }, 'findBooks')
@@ -164,9 +165,9 @@ class SearchController {
   async findCovers(req, res) {
     const query = req.query
     const podcast = query.podcast === '1' || query.podcast === 1
-    const title = query.title || ''
+    const title = getQueryParamAsString(query.title, '')
-    const author = query.author || ''
+    const author = getQueryParamAsString(query.author, '')
-    const provider = query.provider || 'google'
+    const provider = getQueryParamAsString(query.provider, 'google')
 
     // Validate required title
     const titleValidation = SearchController.validateRequiredString(title, 'title', 'findCovers')
@@ -190,8 +191,8 @@ class SearchController {
    * @param {Response} res
    */
   async findPodcasts(req, res) {
-    const term = req.query.term
+    const term = getQueryParamAsString(req.query.term)
-    const country = req.query.country || 'us'
+    const country = getQueryParamAsString(req.query.country, 'us')
 
     // Validate required term
     const termValidation = SearchController.validateRequiredString(term, 'term', 'findPodcasts')
@@ -212,7 +213,7 @@ class SearchController {
    * @param {Response} res
    */
   async findAuthor(req, res) {
-    const query = req.query.q
+    const query = getQueryParamAsString(req.query.q)
 
     // Validate query parameter
     const validation = SearchController.validateRequiredString(query, 'query', 'findAuthor')
@@ -229,8 +230,8 @@ class SearchController {
    * @param {Response} res
    */
   async findChapters(req, res) {
-    const asin = req.query.asin
+    const asin = getQueryParamAsString(req.query.asin)
-    const region = (req.query.region || 'us').toLowerCase()
+    const region = getQueryParamAsString(req.query.region, 'us').toLowerCase()
 
     // Validate ASIN parameter
     const asinValidation = SearchController.validateRequiredString(asin, 'asin', 'findChapters')

server/finders/BookFinder.js

@@ -402,7 +402,8 @@ class BookFinder {
       let authorCandidates = new BookFinder.AuthorCandidates(cleanAuthor, this.audnexus)
 
       // Remove underscores and parentheses with their contents, and replace with a separator
-      const cleanTitle = title.replace(/\[.*?\]|\(.*?\)|{.*?}|_/g, ' - ')
+      // Use negated character classes to prevent ReDoS vulnerability
+      const cleanTitle = title.replace(/\[[^\]]*\]|\([^)]*\)|{[^}]*}|_/g, ' - ')
       // Split title into hypen-separated parts
       const titleParts = cleanTitle.split(/ - | -|- /)
       for (const titlePart of titleParts) authorCandidates.add(titlePart)
@@ -668,7 +669,9 @@ function cleanTitleForCompares(title, keepSubtitle = false) {
   let stripped = keepSubtitle ? title : stripSubtitle(title)
 
   // Remove text in paranthesis (i.e. "Ender's Game (Ender's Saga)" becomes "Ender's Game")
-  let cleaned = stripped.replace(/ *\([^)]*\) */g, '')
+  // Use a safe two-pass approach to prevent ReDoS vulnerability
+  let cleaned = stripped.replace(/\([^)]*\)/g, '') // Remove parenthetical content
+  cleaned = cleaned.replace(/\s+/g, ' ').trim() // Clean up any resulting multiple spaces
 
   // Remove single quotes (i.e. "Ender's Game" becomes "Enders Game")
   cleaned = cleaned.replace(/'/g, '')

server/utils/index.js

@@ -277,3 +277,22 @@ module.exports.timestampToSeconds = (timestamp) => {
   }
   return null
 }
+
+/**
+ * Safely extracts a query parameter as a string, rejecting arrays to prevent type confusion
+ * Express query parameters can be arrays if the same parameter appears multiple times
+ * @example ?author=Smith => "Smith"
+ * @example ?author=Smith&author=Jones => null (array detected)
+ *
+ * @param {any} value - Query parameter value
+ * @param {string} defaultValue - Default value if undefined/null
+ * @returns {string|null} String value or null if invalid (array)
+ */
+module.exports.getQueryParamAsString = (value, defaultValue = '') => {
+  // Explicitly reject arrays to prevent type confusion
+  if (Array.isArray(value)) {
+    return null
+  }
+  // Return default for undefined/null, otherwise return the value
+  return value == null ? defaultValue : value
+}