40 lines
1.4 KiB
Python
40 lines
1.4 KiB
Python
import os
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from asyncio import log
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def resolve_path_within_directory(
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base_dir: str,
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unsafe_path: str,
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*,
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require_file: bool = True,
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) -> str:
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# 用户传入的路径可能是文件名、相对路径、绝对路径，也可能夹带 `../`。
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# 这里统一解析成真实路径，并用 commonpath 判断它是否仍在允许目录内。
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# 这样比简单判断字符串前缀可靠，可以覆盖符号链接、重复分隔符、相对路径
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# 等场景，适用于上传目录、素材目录、任务产物目录这类白名单目录。
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if not unsafe_path:
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raise ValueError("empty path is not allowed")
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base_dir_real = os.path.realpath(base_dir)
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candidate_path = unsafe_path
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if not os.path.isabs(candidate_path):
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candidate_path = os.path.join(base_dir_real, candidate_path)
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resolved_path = os.path.realpath(candidate_path)
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try:
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common_path = os.path.commonpath([base_dir_real, resolved_path])
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except ValueError as exc:
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# Windows 下不同盘符会触发 ValueError，这类路径一定不属于允许目录。
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raise ValueError("path is outside the allowed directory") from exc
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if common_path != base_dir_real:
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raise ValueError("path is outside the allowed directory")
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if require_file and not os.path.isfile(resolved_path):
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raise ValueError("file does not exist")
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return resolved_path
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