🔒 feat: Implement Granular File Storage Strategies and Access Control Middleware

api/server/middleware/accessResources/fileAccess.js

@@ -0,0 +1,124 @@
+const { logger } = require('@librechat/data-schemas');
+const { PERMISSION_BITS, hasPermissions } = require('librechat-data-provider');
+const { getEffectivePermissions } = require('~/server/services/PermissionService');
+const { getFiles } = require('~/models/File');
+const { getAgent } = require('~/models/Agent');
+
+/**
+ * Checks if user has access to a file through agent permissions
+ * Files inherit permissions from agents - if you can view the agent, you can access its files
+ */
+const checkAgentBasedFileAccess = async (userId, fileId) => {
+  try {
+    // Find agents that have this file in their tool_resources
+    const agentsWithFile = await getAgent({
+      $or: [
+        { 'tool_resources.file_search.file_ids': fileId },
+        { 'tool_resources.execute_code.file_ids': fileId },
+        { 'tool_resources.ocr.file_ids': fileId },
+      ],
+    });
+
+    if (!agentsWithFile || agentsWithFile.length === 0) {
+      return false;
+    }
+
+    // Check if user has access to any of these agents
+    for (const agent of Array.isArray(agentsWithFile) ? agentsWithFile : [agentsWithFile]) {
+      // Check if user is the agent author
+      if (agent.author && agent.author.toString() === userId) {
+        logger.debug(`[fileAccess] User is author of agent ${agent.id}`);
+        return true;
+      }
+
+      // Check ACL permissions for VIEW access on the agent
+      try {
+        const permissions = await getEffectivePermissions({
+          userId,
+          resourceType: 'agent',
+          resourceId: agent._id || agent.id,
+        });
+
+        if (hasPermissions(permissions, PERMISSION_BITS.VIEW)) {
+          logger.debug(`[fileAccess] User ${userId} has VIEW permissions on agent ${agent.id}`);
+          return true;
+        }
+      } catch (permissionError) {
+        logger.warn(
+          `[fileAccess] Permission check failed for agent ${agent.id}:`,
+          permissionError.message,
+        );
+        // Continue checking other agents
+      }
+    }
+
+    return false;
+  } catch (error) {
+    logger.error('[fileAccess] Error checking agent-based access:', error);
+    return false;
+  }
+};
+
+/**
+ * Middleware to check if user can access a file
+ * Checks: 1) File ownership, 2) Agent-based access (file inherits agent permissions)
+ */
+const fileAccess = async (req, res, next) => {
+  try {
+    const fileId = req.params.file_id;
+    const userId = req.user?.id;
+
+    if (!fileId) {
+      return res.status(400).json({
+        error: 'Bad Request',
+        message: 'file_id is required',
+      });
+    }
+
+    if (!userId) {
+      return res.status(401).json({
+        error: 'Unauthorized',
+        message: 'Authentication required',
+      });
+    }
+
+    // Get the file
+    const [file] = await getFiles({ file_id: fileId });
+    if (!file) {
+      return res.status(404).json({
+        error: 'Not Found',
+        message: 'File not found',
+      });
+    }
+
+    // Check if user owns the file
+    if (file.user && file.user.toString() === userId) {
+      req.fileAccess = { file };
+      return next();
+    }
+
+    // Check agent-based access (file inherits agent permissions)
+    const hasAgentAccess = await checkAgentBasedFileAccess(userId, fileId);
+    if (hasAgentAccess) {
+      req.fileAccess = { file };
+      return next();
+    }
+
+    // No access
+    logger.warn(`[fileAccess] User ${userId} denied access to file ${fileId}`);
+    return res.status(403).json({
+      error: 'Forbidden',
+      message: 'Insufficient permissions to access this file',
+    });
+  } catch (error) {
+    logger.error('[fileAccess] Error checking file access:', error);
+    return res.status(500).json({
+      error: 'Internal Server Error',
+      message: 'Failed to check file access permissions',
+    });
+  }
+};
+
+module.exports = {
+  fileAccess,
+};