95 lines
2.6 KiB
Python
95 lines
2.6 KiB
Python
# This file is part of Radicale Server - Calendar Server
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#
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# This library is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Radicale. If not, see <http://www.gnu.org/licenses/>.
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"""
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Helper functions for working with paths.
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"""
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import os
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import posixpath
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from . import log
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def sanitize_path(path):
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"""Make path absolute with leading slash to prevent access to other data.
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Preserve a potential trailing slash.
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"""
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trailing_slash = "/" if path.endswith("/") else ""
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path = posixpath.normpath(path)
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new_path = "/"
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for part in path.split("/"):
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if not part or part in (".", ".."):
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continue
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new_path = posixpath.join(new_path, part)
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trailing_slash = "" if new_path.endswith("/") else trailing_slash
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return new_path + trailing_slash
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def is_safe_path_component(path):
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"""Check if path is a single component of a POSIX path.
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Check that the path is safe to join too.
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"""
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if not path:
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return False
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if posixpath.split(path)[0]:
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return False
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if path in (".", ".."):
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return False
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return True
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def is_safe_filesystem_path_component(path):
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"""Check if path is a single component of a filesystem path.
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Check that the path is safe to join too.
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"""
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if not path:
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return False
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drive, _ = os.path.splitdrive(path)
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if drive:
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return False
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head, _ = os.path.split(path)
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if head:
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return False
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if path in (os.curdir, os.pardir):
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return False
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return True
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def path_to_filesystem(path, base_folder):
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"""Convert path to a local filesystem path relative to base_folder.
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Conversion is done in a secure manner, or raises ``ValueError``.
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"""
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sane_path = sanitize_path(path).strip("/")
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safe_path = base_folder
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if not sane_path:
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return safe_path
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for part in sane_path.split("/"):
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if not is_safe_filesystem_path_component(part):
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log.LOGGER.debug(
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"Can't translate path safely to filesystem: %s", path)
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raise ValueError("Unsafe path")
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safe_path = os.path.join(safe_path, part)
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return safe_path
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