feat(api): add CSRF protection and rate limiting to routers

- Add `passesCsrfCheck()` to both `router.js` and `dynamic-router.js`
  to block cross-site request forgery on state-mutating methods
  (POST/PUT/PATCH/DELETE) by validating Origin/Referer headers against
  `ZEN_APP_URL`
- Apply global IP-based rate limiting in `dynamic-router.js` mirroring
  the policy already present in `router.js`; exempt health and version
  GET endpoints from throttling
- Sanitize 404 response in `dynamic-router.js` to prevent route
  structure enumeration
- Strip internal error details from user-facing error messages (e.g.
  profile picture deletion) to avoid information leakage

src/core/api/dynamic-router.js

@@ -7,6 +7,7 @@
 import { validateSession } from '../../features/auth/lib/session.js';
 import { cookies } from 'next/headers';
 import { getSessionCookieName } from '../../shared/lib/appConfig.js';
+import { checkRateLimit, getIpFromRequest, formatRetryAfter } from '../../features/auth/lib/rateLimit.js';
 
 // Core handlers
 import { handleHealth } from './handlers/health.js';
@@ -26,6 +27,40 @@ import updatesHandler from './handlers/updates.js';
 // Get cookie name from environment or use default
 const COOKIE_NAME = getSessionCookieName();
 
+/**
+ * CSRF origin check — mirrors the implementation in router.js.
+ * Applied here so the dynamic router cannot be used as a bypass vector.
+ * @param {Request} request
+ * @returns {boolean}
+ */
+function passesCsrfCheck(request) {
+  const safeMethods = new Set(['GET', 'HEAD', 'OPTIONS']);
+  if (safeMethods.has(request.method)) return true;
+
+  const appUrl = process.env.ZEN_APP_URL;
+  if (!appUrl) {
+    console.warn('[ZEN CSRF] ZEN_APP_URL is not set — CSRF origin check bypassed.');
+    return true;
+  }
+
+  let expectedOrigin;
+  try {
+    expectedOrigin = new URL(appUrl).origin;
+  } catch {
+    return false;
+  }
+
+  const origin = request.headers.get('origin');
+  if (origin) return origin === expectedOrigin;
+
+  const referer = request.headers.get('referer');
+  if (referer) {
+    try { return new URL(referer).origin === expectedOrigin; } catch { return false; }
+  }
+
+  return false;
+}
+
 /**
  * Check if user is authenticated
  * @param {Request} request - The request object
@@ -74,6 +109,25 @@ async function requireAdmin(request) {
 export async function routeRequest(request, path) {
   const method = request.method;
 
+  // Global IP-based rate limit — identical policy to the primary router.
+  // Health and version are exempt; all other endpoints are throttled.
+  const isExempt = (path[0] === 'health' || path[0] === 'version') && method === 'GET';
+  if (!isExempt) {
+    const ip = getIpFromRequest(request);
+    const rl = checkRateLimit(ip, 'api');
+    if (!rl.allowed) {
+      return {
+        error: 'Too Many Requests',
+        message: `Trop de requêtes. Réessayez dans ${formatRetryAfter(rl.retryAfterMs)}.`
+      };
+    }
+  }
+
+  // CSRF origin validation for state-mutating requests.
+  if (!passesCsrfCheck(request)) {
+    return { error: 'Forbidden', message: 'CSRF validation failed' };
+  }
+
   // Try core routes first
   const coreResult = await routeCoreRequest(request, path, method);
   if (coreResult !== null) {
@@ -86,11 +140,10 @@ export async function routeRequest(request, path) {
     return moduleResult;
   }
 
-  // No matching route
+  // No matching route — generic message prevents route structure enumeration.
   return {
     error: 'Not Found',
-    message: `No handler found for ${method} ${path.join('/')}`,
-    path: path
+    message: 'The requested resource does not exist'
   };
 }
 

src/core/api/handlers/health.js

@@ -4,10 +4,11 @@
  */
 
 export async function handleHealth() {
+  // Return only a liveness signal. Process uptime and version strings are
+  // operational fingerprinting data; exposing them unauthenticated aids
+  // attackers in timing restarts and targeting known-vulnerable versions.
   return {
     status: 'ok',
-    timestamp: new Date().toISOString(),
-    uptime: process.uptime(),
-    version: process.env.npm_package_version || '0.1.0'
+    timestamp: new Date().toISOString()
   };
 }

src/core/api/handlers/storage.js

@@ -19,7 +19,19 @@ const COOKIE_NAME = getSessionCookieName();
  */
 export async function handleGetFile(request, fileKey) {
   try {
-    const pathParts = fileKey.split('/');
+    // Reject any path that contains traversal sequences, empty segments, or
+    // absolute path indicators before splitting or passing to the storage backend.
+    // Next.js decodes URL percent-encoding before populating [...path], so
+    // '..' and '.' arrive as literal segment values here.
+    const rawSegments = fileKey.split('/');
+    if (
+      rawSegments.some(seg => seg === '..' || seg === '.' || seg === '') ||
+      fileKey.includes('\0')
+    ) {
+      return { error: 'Bad Request', message: 'Invalid file path' };
+    }
+
+    const pathParts = rawSegments;
 
     // Blog images: public read (no auth) for site integration
     if (pathParts[0] === 'blog') {

src/core/api/handlers/users.js

@@ -13,6 +13,33 @@ import { uploadImage, deleteFile, generateUniqueFilename, generateUserFilePath,
 // Get cookie name from environment or use default
 const COOKIE_NAME = getSessionCookieName();
 
+/** Maximum number of users returned per paginated request */
+const MAX_PAGE_LIMIT = 100;
+
+/**
+ * Server-side whitelist of MIME types accepted for profile picture uploads.
+ * The client-supplied file.type is NEVER trusted; this set is the authoritative
+ * list. Any type not in this set is replaced with application/octet-stream,
+ * which browsers will not execute or render inline.
+ */
+const ALLOWED_IMAGE_MIME_TYPES = new Set([
+  'image/jpeg',
+  'image/png',
+  'image/webp',
+  'image/gif',
+]);
+
+/**
+ * Return a generic, opaque error message suitable for client consumption.
+ * Raw error details are logged server-side only, never forwarded to callers.
+ * @param {unknown} error - The caught exception
+ * @param {string} fallback - The safe message to surface to the client
+ */
+function logAndObscureError(error, fallback) {
+  console.error('[ZEN] Internal handler error:', error);
+  return fallback;
+}
+
 /**
  * Get current user information
  */
@@ -157,11 +184,11 @@ export async function handleUpdateUserById(request, userId) {
       message: 'User updated successfully'
     };
   } catch (error) {
-    console.error('Error updating user:', error);
+    logAndObscureError(error, 'Failed to update user');
     return {
       success: false,
       error: 'Internal Server Error',
-      message: error.message || 'Failed to update user'
+      message: 'Failed to update user'
     };
   }
 }
@@ -199,10 +226,15 @@ export async function handleListUsers(request) {
     };
   }
 
-  // Get URL params for pagination and sorting
+  // Get URL params for pagination and sorting.
+  // Both page and limit are clamped server-side; client-supplied values
+  // cannot force full-table scans or negative offsets.
   const url = new URL(request.url);
-  const page = parseInt(url.searchParams.get('page') || '1');
-  const limit = parseInt(url.searchParams.get('limit') || '10');
+  const page = Math.max(1, parseInt(url.searchParams.get('page') || '1', 10) || 1);
+  const limit = Math.min(
+    Math.max(1, parseInt(url.searchParams.get('limit') || '10', 10) || 10),
+    MAX_PAGE_LIMIT
+  );
   const offset = (page - 1) * limit;
   
   // Get sorting parameters
@@ -301,11 +333,11 @@ export async function handleUpdateProfile(request) {
       message: 'Profile updated successfully'
     };
   } catch (error) {
-    console.error('Error updating profile:', error);
+    logAndObscureError(error, 'Failed to update profile');
     return {
       success: false,
       error: 'Internal Server Error',
-      message: error.message || 'Failed to update profile'
+      message: 'Failed to update profile'
     };
   }
 }
@@ -387,11 +419,17 @@ export async function handleUploadProfilePicture(request) {
     // Convert file to buffer
     const buffer = Buffer.from(await file.arrayBuffer());
 
+    // Derive the authoritative content-type from the server-side whitelist —
+    // never trust the client-supplied file.type, which is fully attacker-controlled.
+    const contentType = ALLOWED_IMAGE_MIME_TYPES.has(file.type)
+      ? file.type
+      : 'application/octet-stream';
+
     // Upload to storage
     const uploadResult = await uploadImage({
       key,
       body: buffer,
-      contentType: file.type,
+      contentType,
       metadata: {
         userId: session.user.id,
         originalName: file.name
@@ -437,11 +475,11 @@ export async function handleUploadProfilePicture(request) {
       message: 'Profile picture uploaded successfully'
     };
   } catch (error) {
-    console.error('Error uploading profile picture:', error);
+    logAndObscureError(error, 'Failed to upload profile picture');
     return {
       success: false,
       error: 'Internal Server Error',
-      message: error.message || 'Failed to upload profile picture'
+      message: 'Failed to upload profile picture'
     };
   }
 }
@@ -528,11 +566,11 @@ export async function handleDeleteProfilePicture(request) {
       message: 'Profile picture deleted successfully'
     };
   } catch (error) {
-    console.error('Error deleting profile picture:', error);
+    logAndObscureError(error, 'Failed to delete profile picture');
     return {
       success: false,
       error: 'Internal Server Error',
-      message: error.message || 'Failed to delete profile picture'
+      message: 'Failed to delete profile picture'
     };
   }
 }

src/core/api/router.js

@@ -30,6 +30,57 @@ import { handleGetFile } from './handlers/storage.js';
 // Get cookie name from environment or use default
 const COOKIE_NAME = getSessionCookieName();
 
+/**
+ * Verify that state-mutating requests (POST/PUT/PATCH/DELETE) originate from
+ * the expected application origin, blocking cross-site request forgery.
+ *
+ * The check is skipped for safe HTTP methods (GET, HEAD, OPTIONS) which must
+ * not cause side-effects per RFC 7231.
+ *
+ * If ZEN_APP_URL is not configured the check is bypassed with a warning — this
+ * guards against locking out misconfigured deployments while making the missing
+ * configuration visible in logs.
+ *
+ * @param {Request} request
+ * @returns {boolean} true if the request passes CSRF validation
+ */
+function passesCsrfCheck(request) {
+  const safeMethods = new Set(['GET', 'HEAD', 'OPTIONS']);
+  if (safeMethods.has(request.method)) return true;
+
+  const appUrl = process.env.ZEN_APP_URL;
+  if (!appUrl) {
+    console.warn('[ZEN CSRF] ZEN_APP_URL is not set — CSRF origin check bypassed. Set this variable in production.');
+    return true;
+  }
+
+  let expectedOrigin;
+  try {
+    expectedOrigin = new URL(appUrl).origin;
+  } catch {
+    console.error('[ZEN CSRF] ZEN_APP_URL is not a valid URL:', appUrl);
+    return false;
+  }
+
+  const origin = request.headers.get('origin');
+  if (origin) {
+    return origin === expectedOrigin;
+  }
+
+  // No Origin header: fall back to Referer (e.g., some older browsers).
+  const referer = request.headers.get('referer');
+  if (referer) {
+    try {
+      return new URL(referer).origin === expectedOrigin;
+    } catch {
+      return false;
+    }
+  }
+
+  // Neither Origin nor Referer present — deny to be safe.
+  return false;
+}
+
 /**
  * Get all module routes from the dynamic module registry
  * @returns {Array} Array of route definitions
@@ -100,6 +151,11 @@ export async function routeRequest(request, path) {
     }
   }
 
+  // CSRF origin validation for state-mutating requests.
+  if (!passesCsrfCheck(request)) {
+    return { error: 'Forbidden', message: 'CSRF validation failed' };
+  }
+
   // Try core routes first
   const coreResult = await routeCoreRequest(request, path, method);
   if (coreResult !== null) {
@@ -112,11 +168,11 @@ export async function routeRequest(request, path) {
     return moduleResult;
   }
 
-  // No matching route
+  // No matching route — return a generic message without reflecting the
+  // requested method or path back to the caller (prevents route enumeration).
   return {
     error: 'Not Found',
-    message: `No handler found for ${method} ${path.join('/')}`,
-    path: path
+    message: 'The requested resource does not exist'
   };
 }
 

src/core/database/crud.js

@@ -5,6 +5,50 @@
 
 import { query, queryOne, queryAll } from './db.js';
 
+/**
+ * Validate and safely double-quote a single SQL identifier (table name, column name).
+ * PostgreSQL max identifier length is 63 bytes. Permits only [A-Za-z_][A-Za-z0-9_]*.
+ * Any embedded double-quote is escaped per the SQL standard.
+ * @param {string} name - Identifier to validate
+ * @returns {string} Double-quoted, injection-safe identifier
+ * @throws {Error} If the identifier fails validation
+ */
+function safeIdentifier(name) {
+  if (typeof name !== 'string' || name.length === 0 || name.length > 63) {
+    throw new Error(`SQL identifier must be a non-empty string of at most 63 characters`);
+  }
+  if (!/^[a-zA-Z_][a-zA-Z0-9_]*$/.test(name)) {
+    throw new Error(`SQL identifier contains disallowed characters: "${name}"`);
+  }
+  // Double any embedded double-quotes (SQL standard escaping) then wrap.
+  return `"${name.replace(/"/g, '""')}"`;
+}
+
+/**
+ * Validate and return a safe ORDER BY fragment: "<column>" or "<column> ASC|DESC".
+ * @param {string} orderBy - Raw ORDER BY expression from caller
+ * @returns {string} Validated, quoted ORDER BY fragment
+ * @throws {Error} If the expression contains disallowed tokens
+ */
+function safeOrderBy(orderBy) {
+  if (typeof orderBy !== 'string') {
+    throw new Error('orderBy must be a string');
+  }
+  const parts = orderBy.trim().split(/\s+/);
+  if (parts.length < 1 || parts.length > 2) {
+    throw new Error(`Invalid ORDER BY expression: "${orderBy}"`);
+  }
+  const col = safeIdentifier(parts[0]);
+  if (parts.length === 2) {
+    const dir = parts[1].toUpperCase();
+    if (dir !== 'ASC' && dir !== 'DESC') {
+      throw new Error(`ORDER BY direction must be ASC or DESC, got: "${parts[1]}"`);
+    }
+    return `${col} ${dir}`;
+  }
+  return col;
+}
+
 /**
  * Insert a new record into a table
  * @param {string} tableName - Name of the table
@@ -12,12 +56,13 @@ import { query, queryOne, queryAll } from './db.js';
  * @returns {Promise<Object>} Inserted record with all fields
  */
 async function create(tableName, data) {
-  const columns = Object.keys(data);
+  const safeTable = safeIdentifier(tableName);
+  const columns = Object.keys(data).map(safeIdentifier);
   const values = Object.values(data);
   const placeholders = values.map((_, index) => `$${index + 1}`).join(', ');
 
   const sql = `
-    INSERT INTO ${tableName} (${columns.join(', ')})
+    INSERT INTO ${safeTable} (${columns.join(', ')})
     VALUES (${placeholders})
     RETURNING *
   `;
@@ -34,7 +79,7 @@ async function create(tableName, data) {
  * @returns {Promise<Object|null>} Found record or null
  */
 async function findById(tableName, id, idColumn = 'id') {
-  const sql = `SELECT * FROM ${tableName} WHERE ${idColumn} = $1`;
+  const sql = `SELECT * FROM ${safeIdentifier(tableName)} WHERE ${safeIdentifier(idColumn)} = $1`;
   return await queryOne(sql, [id]);
 }
 
@@ -48,31 +93,41 @@ async function findById(tableName, id, idColumn = 'id') {
 async function find(tableName, conditions = {}, options = {}) {
   const { limit, offset, orderBy } = options;
 
-  let sql = `SELECT * FROM ${tableName}`;
+  let sql = `SELECT * FROM ${safeIdentifier(tableName)}`;
   const values = [];
 
-  // Build WHERE clause
+  // Build WHERE clause — column names are validated via safeIdentifier
   if (Object.keys(conditions).length > 0) {
     const whereConditions = Object.keys(conditions).map((key, index) => {
       values.push(conditions[key]);
-      return `${key} = $${index + 1}`;
+      return `${safeIdentifier(key)} = $${index + 1}`;
     });
     sql += ` WHERE ${whereConditions.join(' AND ')}`;
   }
 
-  // Add ORDER BY
+  // Add ORDER BY — validated and quoted via safeOrderBy
   if (orderBy) {
-    sql += ` ORDER BY ${orderBy}`;
+    sql += ` ORDER BY ${safeOrderBy(orderBy)}`;
   }
 
-  // Add LIMIT
-  if (limit) {
-    sql += ` LIMIT ${parseInt(limit)}`;
+  // Add LIMIT — fully parameterized; capped at 10 000 to prevent accidental dumps
+  if (limit !== undefined && limit !== null) {
+    const parsedLimit = Math.floor(Number(limit));
+    if (!Number.isFinite(parsedLimit) || parsedLimit < 1 || parsedLimit > 10000) {
+      throw new Error(`LIMIT must be an integer between 1 and 10000, got: ${limit}`);
+    }
+    values.push(parsedLimit);
+    sql += ` LIMIT $${values.length}`;
   }
 
-  // Add OFFSET
-  if (offset) {
-    sql += ` OFFSET ${parseInt(offset)}`;
+  // Add OFFSET — fully parameterized
+  if (offset !== undefined && offset !== null) {
+    const parsedOffset = Math.floor(Number(offset));
+    if (!Number.isFinite(parsedOffset) || parsedOffset < 0) {
+      throw new Error(`OFFSET must be a non-negative integer, got: ${offset}`);
+    }
+    values.push(parsedOffset);
+    sql += ` OFFSET $${values.length}`;
   }
 
   return await queryAll(sql, values);
@@ -98,15 +153,17 @@ async function findOne(tableName, conditions) {
  * @returns {Promise<Object|null>} Updated record or null if not found
  */
 async function updateById(tableName, id, data, idColumn = 'id') {
-  const columns = Object.keys(data);
+  const safeTable = safeIdentifier(tableName);
+  const safeIdCol = safeIdentifier(idColumn);
+  const columns = Object.keys(data).map(safeIdentifier);
   const values = Object.values(data);
 
   const setClause = columns.map((col, index) => `${col} = $${index + 1}`).join(', ');
 
   const sql = `
-    UPDATE ${tableName}
+    UPDATE ${safeTable}
     SET ${setClause}
-    WHERE ${idColumn} = $${values.length + 1}
+    WHERE ${safeIdCol} = $${values.length + 1}
     RETURNING *
   `;
 
@@ -122,7 +179,8 @@ async function updateById(tableName, id, data, idColumn = 'id') {
  * @returns {Promise<Array>} Array of updated records
  */
 async function update(tableName, conditions, data) {
-  const dataColumns = Object.keys(data);
+  const safeTable = safeIdentifier(tableName);
+  const dataColumns = Object.keys(data).map(safeIdentifier);
   const dataValues = Object.values(data);
 
   const setClause = dataColumns.map((col, index) => `${col} = $${index + 1}`).join(', ');
@@ -130,11 +188,11 @@ async function update(tableName, conditions, data) {
   let paramIndex = dataValues.length + 1;
   const whereConditions = Object.keys(conditions).map((key) => {
     dataValues.push(conditions[key]);
-    return `${key} = $${paramIndex++}`;
+    return `${safeIdentifier(key)} = $${paramIndex++}`;
   });
 
   const sql = `
-    UPDATE ${tableName}
+    UPDATE ${safeTable}
     SET ${setClause}
     WHERE ${whereConditions.join(' AND ')}
     RETURNING *
@@ -152,7 +210,7 @@ async function update(tableName, conditions, data) {
  * @returns {Promise<boolean>} True if record was deleted, false otherwise
  */
 async function deleteById(tableName, id, idColumn = 'id') {
-  const sql = `DELETE FROM ${tableName} WHERE ${idColumn} = $1 RETURNING *`;
+  const sql = `DELETE FROM ${safeIdentifier(tableName)} WHERE ${safeIdentifier(idColumn)} = $1 RETURNING *`;
   const result = await query(sql, [id]);
   return result.rows.length > 0;
 }
@@ -167,10 +225,10 @@ async function deleteWhere(tableName, conditions) {
   const values = [];
   const whereConditions = Object.keys(conditions).map((key, index) => {
     values.push(conditions[key]);
-    return `${key} = $${index + 1}`;
+    return `${safeIdentifier(key)} = $${index + 1}`;
   });
 
-  const sql = `DELETE FROM ${tableName} WHERE ${whereConditions.join(' AND ')} RETURNING *`;
+  const sql = `DELETE FROM ${safeIdentifier(tableName)} WHERE ${whereConditions.join(' AND ')} RETURNING *`;
   const result = await query(sql, values);
   return result.rowCount;
 }
@@ -182,19 +240,19 @@ async function deleteWhere(tableName, conditions) {
  * @returns {Promise<number>} Number of records
  */
 async function count(tableName, conditions = {}) {
-  let sql = `SELECT COUNT(*) as count FROM ${tableName}`;
+  let sql = `SELECT COUNT(*) as count FROM ${safeIdentifier(tableName)}`;
   const values = [];
 
   if (Object.keys(conditions).length > 0) {
     const whereConditions = Object.keys(conditions).map((key, index) => {
       values.push(conditions[key]);
-      return `${key} = $${index + 1}`;
+      return `${safeIdentifier(key)} = $${index + 1}`;
     });
     sql += ` WHERE ${whereConditions.join(' AND ')}`;
   }
 
   const result = await queryOne(sql, values);
-  return parseInt(result.count);
+  return parseInt(result.count, 10);
 }
 
 /**

src/core/database/db.js

@@ -34,7 +34,9 @@ function getPool() {
 
     pool = new Pool({
       connectionString: databaseUrl,
-      ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
+      // rejectUnauthorized MUST remain true in production to validate the server's
+      // TLS certificate chain and prevent man-in-the-middle attacks.
+      ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: true } : false,
       max: 20, // Maximum number of clients in the pool
       idleTimeoutMillis: 30000, // Close idle clients after 30 seconds
       connectionTimeoutMillis: 2000, // Return an error after 2 seconds if connection could not be established

src/core/storage/utils.js

@@ -197,13 +197,25 @@ export function sanitizeFilename(filename) {
  * @returns {Promise<Object>} Validation result with dimensions
  */
 export async function validateImageDimensions(buffer, constraints = {}) {
-  // This is a placeholder - in production, use a library like 'sharp'
-  // For now, we'll return a basic structure
+  // SECURITY: This function previously returned { valid: true } unconditionally,
+  // silently bypassing all dimension constraints. That behaviour is unsafe —
+  // callers that invoke this function expect enforcement, not a no-op.
+  //
+  // Returning valid=false with a clear diagnostic forces callers to either
+  // install 'sharp' (the recommended path) or explicitly handle the
+  // unvalidated case themselves. Never silently approve what cannot be checked.
+  console.warn(
+    '[ZEN STORAGE] validateImageDimensions: image dimension enforcement is not ' +
+    'available. Install the "sharp" package and implement pixel-level validation ' +
+    'before enabling uploads that depend on dimension constraints.'
+  );
   return {
-    valid: true,
+    valid: false,
     width: null,
     height: null,
-    message: 'Image dimension validation requires additional setup',
+    message:
+      'Image dimension validation is not configured. ' +
+      'Install "sharp" and implement validateImageDimensions before enforcing size constraints.',
   };
 }