Initial commit

api/utils/pathSafety.ts

@@ -0,0 +1,106 @@
+import path from 'path'
+import fs from 'fs/promises'
+import { NOTEBOOK_ROOT } from '../config/paths.js'
+import { AccessDeniedError } from '../../shared/errors/index.js'
+
+const DANGEROUS_PATTERNS = [
+  /\.\./,
+  /\0/,
+  /%2e%2e[%/]/i,
+  /%252e%252e[%/]/i,
+  /\.\.%2f/i,
+  /\.\.%5c/i,
+  /%c0%ae/i,
+  /%c1%9c/i,
+  /%c0%ae%c0%ae/i,
+  /%c1%9c%c1%9c/i,
+  /\.\.%c0%af/i,
+  /\.\.%c1%9c/i,
+  /%252e/i,
+  /%uff0e/i,
+  /%u002e/i,
+]
+
+const WINDOWS_RESERVED_NAMES = /^(CON|PRN|AUX|NUL|COM[1-9]|LPT[1-9]|CLOCK\$)$/i
+
+const DOUBLE_ENCODE_PATTERNS = [
+  /%25[0-9a-fA-F]{2}/,
+  /%[0-9a-fA-F]{2}%[0-9a-fA-F]{2}/,
+]
+
+export const normalizeRelPath = (input: string) => {
+  const trimmed = input.replace(/\0/g, '').trim()
+  return trimmed.replace(/^[/\\]+/, '')
+}
+
+export const containsPathTraversal = (input: string): boolean => {
+  const decoded = decodeURIComponentSafe(input)
+  return DANGEROUS_PATTERNS.some(pattern => pattern.test(input) || pattern.test(decoded))
+}
+
+export const containsDoubleEncoding = (input: string): boolean => {
+  return DOUBLE_ENCODE_PATTERNS.some(pattern => pattern.test(input))
+}
+
+export const hasPathSecurityIssues = (input: string): boolean => {
+  return containsPathTraversal(input) || containsDoubleEncoding(input)
+}
+
+const decodeURIComponentSafe = (input: string): string => {
+  try {
+    return decodeURIComponent(input)
+  } catch {
+    return input
+  }
+}
+
+export const resolveNotebookPath = (relPath: string) => {
+  if (hasPathSecurityIssues(relPath)) {
+    throw new AccessDeniedError('Path traversal detected')
+  }
+
+  const safeRelPath = normalizeRelPath(relPath)
+  const notebookRoot = path.resolve(NOTEBOOK_ROOT)
+  const fullPath = path.resolve(notebookRoot, safeRelPath)
+
+  if (!fullPath.startsWith(notebookRoot)) {
+    throw new AccessDeniedError('Access denied')
+  }
+
+  return { safeRelPath, fullPath }
+}
+
+export const resolveNotebookPathSafe = async (relPath: string) => {
+  if (hasPathSecurityIssues(relPath)) {
+    throw new AccessDeniedError('Path traversal detected')
+  }
+
+  const safeRelPath = normalizeRelPath(relPath)
+  const notebookRoot = path.resolve(NOTEBOOK_ROOT)
+  const fullPath = path.resolve(notebookRoot, safeRelPath)
+
+  try {
+    await fs.access(fullPath)
+  } catch {
+    return { safeRelPath, fullPath, realPath: null }
+  }
+
+  const realFullPath = await fs.realpath(fullPath)
+  const realRoot = await fs.realpath(notebookRoot)
+
+  if (!realFullPath.startsWith(realRoot)) {
+    throw new AccessDeniedError('Symbolic link escapes notebook root')
+  }
+
+  return { safeRelPath, fullPath, realPath: realFullPath }
+}
+
+export const validateFileName = (name: string): boolean => {
+  if (!name || name.length === 0) return false
+  if (name.length > 255) return false
+  const invalidChars = /[<>:"/\\|?*\x00-\x1f]/
+  if (invalidChars.test(name)) return false
+  if (WINDOWS_RESERVED_NAMES.test(name)) return false
+  if (name.startsWith('.') || name.endsWith('.')) return false
+  return true
+}