85d98381df
- Set up main entry point for React application. - Create About, Home, NotFound, Privacy, and Terms pages with SEO support. - Implement API service for file uploads and task management. - Add global styles using Tailwind CSS. - Create utility functions for SEO and text processing. - Configure Vite for development and production builds. - Set up Nginx configuration for serving frontend and backend. - Add scripts for cleanup of expired files and sitemap generation. - Implement deployment script for production environment.
112 lines
3.5 KiB
Python
112 lines
3.5 KiB
Python
"""File validation utilities — multi-layer security checks."""
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import os
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import magic
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from flask import current_app
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from werkzeug.utils import secure_filename
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class FileValidationError(Exception):
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"""Custom exception for file validation failures."""
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def __init__(self, message: str, code: int = 400):
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self.message = message
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self.code = code
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super().__init__(self.message)
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def validate_file(file_storage, allowed_types: list[str] | None = None):
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"""
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Validate an uploaded file through multiple security layers.
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Args:
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file_storage: Flask FileStorage object from request.files
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allowed_types: List of allowed extensions (e.g., ["pdf", "docx"]).
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If None, uses all allowed extensions from config.
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Returns:
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tuple: (sanitized_filename, detected_extension)
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Raises:
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FileValidationError: If validation fails at any layer.
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"""
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config = current_app.config
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# Layer 1: Check if file exists and has a filename
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if not file_storage or file_storage.filename == "":
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raise FileValidationError("No file provided.")
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filename = secure_filename(file_storage.filename)
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if not filename:
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raise FileValidationError("Invalid filename.")
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# Layer 2: Check file extension against whitelist
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ext = _get_extension(filename)
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allowed_extensions = config.get("ALLOWED_EXTENSIONS", {})
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if allowed_types:
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valid_extensions = {k: v for k, v in allowed_extensions.items() if k in allowed_types}
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else:
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valid_extensions = allowed_extensions
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if ext not in valid_extensions:
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raise FileValidationError(
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f"File type '.{ext}' is not allowed. "
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f"Allowed types: {', '.join(valid_extensions.keys())}"
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)
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# Layer 3: Check file size against type-specific limits
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file_storage.seek(0, os.SEEK_END)
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file_size = file_storage.tell()
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file_storage.seek(0)
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size_limits = config.get("FILE_SIZE_LIMITS", {})
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max_size = size_limits.get(ext, 20 * 1024 * 1024) # Default 20MB
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if file_size > max_size:
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max_mb = max_size / (1024 * 1024)
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raise FileValidationError(
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f"File too large. Maximum size for .{ext} files is {max_mb:.0f}MB."
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)
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if file_size == 0:
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raise FileValidationError("File is empty.")
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# Layer 4: Check MIME type using magic bytes
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file_header = file_storage.read(8192)
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file_storage.seek(0)
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detected_mime = magic.from_buffer(file_header, mime=True)
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expected_mimes = valid_extensions.get(ext, [])
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if detected_mime not in expected_mimes:
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raise FileValidationError(
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f"File content does not match extension '.{ext}'. "
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f"Detected type: {detected_mime}"
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)
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# Layer 5: Additional content checks for specific types
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if ext == "pdf":
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_check_pdf_safety(file_header)
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return filename, ext
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def _get_extension(filename: str) -> str:
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"""Extract and normalize file extension."""
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if "." not in filename:
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return ""
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return filename.rsplit(".", 1)[1].lower()
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def _check_pdf_safety(file_header: bytes):
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"""Check PDF for potentially dangerous embedded content."""
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dangerous_patterns = [b"/JS", b"/JavaScript", b"/Launch", b"/EmbeddedFile"]
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header_str = file_header
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for pattern in dangerous_patterns:
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if pattern in header_str:
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raise FileValidationError(
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"PDF contains potentially unsafe content (embedded scripts)."
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)
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