diff --git a/pkgs/development/interpreters/python/cpython/3.14/CVE-2025-4517.patch b/pkgs/development/interpreters/python/cpython/3.14/CVE-2025-4517.patch new file mode 100644 index 000000000000..5ad45fdde9fa --- /dev/null +++ b/pkgs/development/interpreters/python/cpython/3.14/CVE-2025-4517.patch @@ -0,0 +1,2055 @@ +From 9e0ac76d96cf80b49055f6d6b9a6763fb9215c2a Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?=C5=81ukasz=20Langa?= +Date: Tue, 3 Jun 2025 14:05:00 +0200 +Subject: [PATCH] [3.14] gh-135034: Normalize link targets in tarfile, add + `os.path.realpath(strict='allow_missing')` (gh-135037) (gh-135065) +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Addresses CVEs 2024-12718, 2025-4138, 2025-4330, and 2025-4517. + +(cherry picked from commit 3612d8f51741b11f36f8fb0494d79086bac9390a) + +Signed-off-by: Łukasz Langa +Co-authored-by: Petr Viktorin +Co-authored-by: Seth Michael Larson +Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com> +Co-authored-by: Serhiy Storchaka +--- + Doc/library/os.path.rst | 32 +- + Doc/library/tarfile.rst | 20 ++ + Doc/whatsnew/3.14.rst | 32 ++ + Lib/genericpath.py | 11 +- + Lib/ntpath.py | 38 ++- + Lib/posixpath.py | 57 ++-- + Lib/tarfile.py | 163 +++++++-- + Lib/test/test_ntpath.py | 216 ++++++++++-- + Lib/test/test_posixpath.py | 252 +++++++++++--- + Lib/test/test_tarfile.py | 310 +++++++++++++++++- + ...-06-02-11-32-23.gh-issue-135034.RLGjbp.rst | 6 + + 11 files changed, 967 insertions(+), 170 deletions(-) + create mode 100644 Misc/NEWS.d/next/Security/2025-06-02-11-32-23.gh-issue-135034.RLGjbp.rst + +diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst +index ecbbc1d7605f9f..f72aee19d8f332 100644 +--- a/Doc/library/os.path.rst ++++ b/Doc/library/os.path.rst +@@ -408,9 +408,26 @@ the :mod:`glob` module.) + system). On Windows, this function will also resolve MS-DOS (also called 8.3) + style names such as ``C:\\PROGRA~1`` to ``C:\\Program Files``. + +- If a path doesn't exist or a symlink loop is encountered, and *strict* is +- ``True``, :exc:`OSError` is raised. If *strict* is ``False`` these errors +- are ignored, and so the result might be missing or otherwise inaccessible. ++ By default, the path is evaluated up to the first component that does not ++ exist, is a symlink loop, or whose evaluation raises :exc:`OSError`. ++ All such components are appended unchanged to the existing part of the path. ++ ++ Some errors that are handled this way include "access denied", "not a ++ directory", or "bad argument to internal function". Thus, the ++ resulting path may be missing or inaccessible, may still contain ++ links or loops, and may traverse non-directories. ++ ++ This behavior can be modified by keyword arguments: ++ ++ If *strict* is ``True``, the first error encountered when evaluating the path is ++ re-raised. ++ In particular, :exc:`FileNotFoundError` is raised if *path* does not exist, ++ or another :exc:`OSError` if it is otherwise inaccessible. ++ ++ If *strict* is :py:data:`os.path.ALLOW_MISSING`, errors other than ++ :exc:`FileNotFoundError` are re-raised (as with ``strict=True``). ++ Thus, the returned path will not contain any symbolic links, but the named ++ file and some of its parent directories may be missing. + + .. note:: + This function emulates the operating system's procedure for making a path +@@ -429,6 +446,15 @@ the :mod:`glob` module.) + .. versionchanged:: 3.10 + The *strict* parameter was added. + ++ .. versionchanged:: next ++ The :py:data:`~os.path.ALLOW_MISSING` value for the *strict* parameter ++ was added. ++ ++.. data:: ALLOW_MISSING ++ ++ Special value used for the *strict* argument in :func:`realpath`. ++ ++ .. versionadded:: next + + .. function:: relpath(path, start=os.curdir) + +diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst +index f9cb5495e60cd2..7cec108a5bd41d 100644 +--- a/Doc/library/tarfile.rst ++++ b/Doc/library/tarfile.rst +@@ -255,6 +255,15 @@ The :mod:`tarfile` module defines the following exceptions: + Raised to refuse extracting a symbolic link pointing outside the destination + directory. + ++.. exception:: LinkFallbackError ++ ++ Raised to refuse emulating a link (hard or symbolic) by extracting another ++ archive member, when that member would be rejected by the filter location. ++ The exception that was raised to reject the replacement member is available ++ as :attr:`!BaseException.__context__`. ++ ++ .. versionadded:: next ++ + + The following constants are available at the module level: + +@@ -1068,6 +1077,12 @@ reused in custom filters: + Implements the ``'data'`` filter. + In addition to what ``tar_filter`` does: + ++ - Normalize link targets (:attr:`TarInfo.linkname`) using ++ :func:`os.path.normpath`. ++ Note that this removes internal ``..`` components, which may change the ++ meaning of the link if the path in :attr:`!TarInfo.linkname` traverses ++ symbolic links. ++ + - :ref:`Refuse ` to extract links (hard or soft) + that link to absolute paths, or ones that link outside the destination. + +@@ -1099,6 +1114,10 @@ reused in custom filters: + Note that this filter does not block *all* dangerous archive features. + See :ref:`tarfile-further-verification` for details. + ++ .. versionchanged:: next ++ ++ Link targets are now normalized. ++ + + .. _tarfile-extraction-refuse: + +@@ -1127,6 +1146,7 @@ Here is an incomplete list of things to consider: + * Extract to a :func:`new temporary directory ` + to prevent e.g. exploiting pre-existing links, and to make it easier to + clean up after a failed extraction. ++* Disallow symbolic links if you do not need the functionality. + * When working with untrusted data, use external (e.g. OS-level) limits on + disk, memory and CPU usage. + * Check filenames against an allow-list of characters +diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst +index 561d1a8914b50c..1e6a3615963ff4 100644 +--- a/Doc/whatsnew/3.14.rst ++++ b/Doc/whatsnew/3.14.rst +@@ -1608,6 +1608,16 @@ os + (Contributed by Cody Maloney in :gh:`129205`.) + + ++os.path ++------- ++ ++* The *strict* parameter to :func:`os.path.realpath` accepts a new value, ++ :data:`os.path.ALLOW_MISSING`. ++ If used, errors other than :exc:`FileNotFoundError` will be re-raised; ++ the resulting path can be missing but it will be free of symlinks. ++ (Contributed by Petr Viktorin for :cve:`2025-4517`.) ++ ++ + pathlib + ------- + +@@ -1796,6 +1806,28 @@ sysconfig + (Contributed by Xuehai Pan in :gh:`131799`.) + + ++tarfile ++------- ++ ++* :func:`~tarfile.data_filter` now normalizes symbolic link targets in order to ++ avoid path traversal attacks. ++ (Contributed by Petr Viktorin in :gh:`127987` and :cve:`2025-4138`.) ++* :func:`~tarfile.TarFile.extractall` now skips fixing up directory attributes ++ when a directory was removed or replaced by another kind of file. ++ (Contributed by Petr Viktorin in :gh:`127987` and :cve:`2024-12718`.) ++* :func:`~tarfile.TarFile.extract` and :func:`~tarfile.TarFile.extractall` ++ now (re-)apply the extraction filter when substituting a link (hard or ++ symbolic) with a copy of another archive member, and when fixing up ++ directory attributes. ++ The former raises a new exception, :exc:`~tarfile.LinkFallbackError`. ++ (Contributed by Petr Viktorin for :cve:`2025-4330` and :cve:`2024-12718`.) ++* :func:`~tarfile.TarFile.extract` and :func:`~tarfile.TarFile.extractall` ++ no longer extract rejected members when ++ :func:`~tarfile.TarFile.errorlevel` is zero. ++ (Contributed by Matt Prodani and Petr Viktorin in :gh:`112887` ++ and :cve:`2025-4435`.) ++ ++ + threading + --------- + +diff --git a/Lib/genericpath.py b/Lib/genericpath.py +index ba7b0a13c7f81d..9363f564aab7a6 100644 +--- a/Lib/genericpath.py ++++ b/Lib/genericpath.py +@@ -8,7 +8,7 @@ + + __all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime', + 'getsize', 'isdevdrive', 'isdir', 'isfile', 'isjunction', 'islink', +- 'lexists', 'samefile', 'sameopenfile', 'samestat'] ++ 'lexists', 'samefile', 'sameopenfile', 'samestat', 'ALLOW_MISSING'] + + + # Does a path exist? +@@ -189,3 +189,12 @@ def _check_arg_types(funcname, *args): + f'os.PathLike object, not {s.__class__.__name__!r}') from None + if hasstr and hasbytes: + raise TypeError("Can't mix strings and bytes in path components") from None ++ ++# A singleton with a true boolean value. ++@object.__new__ ++class ALLOW_MISSING: ++ """Special value for use in realpath().""" ++ def __repr__(self): ++ return 'os.path.ALLOW_MISSING' ++ def __reduce__(self): ++ return self.__class__.__name__ +diff --git a/Lib/ntpath.py b/Lib/ntpath.py +index 52ff2af743af6c..9cdc16480f9afe 100644 +--- a/Lib/ntpath.py ++++ b/Lib/ntpath.py +@@ -29,7 +29,7 @@ + "abspath","curdir","pardir","sep","pathsep","defpath","altsep", + "extsep","devnull","realpath","supports_unicode_filenames","relpath", + "samefile", "sameopenfile", "samestat", "commonpath", "isjunction", +- "isdevdrive"] ++ "isdevdrive", "ALLOW_MISSING"] + + def _get_bothseps(path): + if isinstance(path, bytes): +@@ -601,9 +601,10 @@ def abspath(path): + from nt import _findfirstfile, _getfinalpathname, readlink as _nt_readlink + except ImportError: + # realpath is a no-op on systems without _getfinalpathname support. +- realpath = abspath ++ def realpath(path, *, strict=False): ++ return abspath(path) + else: +- def _readlink_deep(path): ++ def _readlink_deep(path, ignored_error=OSError): + # These error codes indicate that we should stop reading links and + # return the path we currently have. + # 1: ERROR_INVALID_FUNCTION +@@ -636,7 +637,7 @@ def _readlink_deep(path): + path = old_path + break + path = normpath(join(dirname(old_path), path)) +- except OSError as ex: ++ except ignored_error as ex: + if ex.winerror in allowed_winerror: + break + raise +@@ -645,7 +646,7 @@ def _readlink_deep(path): + break + return path + +- def _getfinalpathname_nonstrict(path): ++ def _getfinalpathname_nonstrict(path, ignored_error=OSError): + # These error codes indicate that we should stop resolving the path + # and return the value we currently have. + # 1: ERROR_INVALID_FUNCTION +@@ -673,17 +674,18 @@ def _getfinalpathname_nonstrict(path): + try: + path = _getfinalpathname(path) + return join(path, tail) if tail else path +- except OSError as ex: ++ except ignored_error as ex: + if ex.winerror not in allowed_winerror: + raise + try: + # The OS could not resolve this path fully, so we attempt + # to follow the link ourselves. If we succeed, join the tail + # and return. +- new_path = _readlink_deep(path) ++ new_path = _readlink_deep(path, ++ ignored_error=ignored_error) + if new_path != path: + return join(new_path, tail) if tail else new_path +- except OSError: ++ except ignored_error: + # If we fail to readlink(), let's keep traversing + pass + # If we get these errors, try to get the real name of the file without accessing it. +@@ -691,7 +693,7 @@ def _getfinalpathname_nonstrict(path): + try: + name = _findfirstfile(path) + path, _ = split(path) +- except OSError: ++ except ignored_error: + path, name = split(path) + else: + path, name = split(path) +@@ -721,6 +723,15 @@ def realpath(path, *, strict=False): + if normcase(path) == devnull: + return '\\\\.\\NUL' + had_prefix = path.startswith(prefix) ++ ++ if strict is ALLOW_MISSING: ++ ignored_error = FileNotFoundError ++ strict = True ++ elif strict: ++ ignored_error = () ++ else: ++ ignored_error = OSError ++ + if not had_prefix and not isabs(path): + path = join(cwd, path) + try: +@@ -728,17 +739,16 @@ def realpath(path, *, strict=False): + initial_winerror = 0 + except ValueError as ex: + # gh-106242: Raised for embedded null characters +- # In strict mode, we convert into an OSError. ++ # In strict modes, we convert into an OSError. + # Non-strict mode returns the path as-is, since we've already + # made it absolute. + if strict: + raise OSError(str(ex)) from None + path = normpath(path) +- except OSError as ex: +- if strict: +- raise ++ except ignored_error as ex: + initial_winerror = ex.winerror +- path = _getfinalpathname_nonstrict(path) ++ path = _getfinalpathname_nonstrict(path, ++ ignored_error=ignored_error) + # The path returned by _getfinalpathname will always start with \\?\ - + # strip off that prefix unless it was already provided on the original + # path. +diff --git a/Lib/posixpath.py b/Lib/posixpath.py +index db72ded8826056..d38f3bd5872bcd 100644 +--- a/Lib/posixpath.py ++++ b/Lib/posixpath.py +@@ -36,7 +36,7 @@ + "samefile","sameopenfile","samestat", + "curdir","pardir","sep","pathsep","defpath","altsep","extsep", + "devnull","realpath","supports_unicode_filenames","relpath", +- "commonpath", "isjunction","isdevdrive"] ++ "commonpath", "isjunction","isdevdrive","ALLOW_MISSING"] + + + def _get_sep(path): +@@ -402,10 +402,18 @@ def realpath(filename, *, strict=False): + curdir = '.' + pardir = '..' + getcwd = os.getcwd +- return _realpath(filename, strict, sep, curdir, pardir, getcwd) ++ if strict is ALLOW_MISSING: ++ ignored_error = FileNotFoundError ++ strict = True ++ elif strict: ++ ignored_error = () ++ else: ++ ignored_error = OSError ++ ++ lstat = os.lstat ++ readlink = os.readlink ++ maxlinks = None + +-def _realpath(filename, strict=False, sep=sep, curdir=curdir, pardir=pardir, +- getcwd=os.getcwd, lstat=os.lstat, readlink=os.readlink, maxlinks=None): + # The stack of unresolved path parts. When popped, a special value of None + # indicates that a symlink target has been resolved, and that the original + # symlink path can be retrieved by popping again. The [::-1] slice is a +@@ -477,27 +485,28 @@ def _realpath(filename, strict=False, sep=sep, curdir=curdir, pardir=pardir, + path = newpath + continue + target = readlink(newpath) +- except OSError: +- if strict: +- raise +- path = newpath ++ except ignored_error: ++ pass ++ else: ++ # Resolve the symbolic link ++ if target.startswith(sep): ++ # Symlink target is absolute; reset resolved path. ++ path = sep ++ if maxlinks is None: ++ # Mark this symlink as seen but not fully resolved. ++ seen[newpath] = None ++ # Push the symlink path onto the stack, and signal its specialness ++ # by also pushing None. When these entries are popped, we'll ++ # record the fully-resolved symlink target in the 'seen' mapping. ++ rest.append(newpath) ++ rest.append(None) ++ # Push the unresolved symlink target parts onto the stack. ++ target_parts = target.split(sep)[::-1] ++ rest.extend(target_parts) ++ part_count += len(target_parts) + continue +- # Resolve the symbolic link +- if target.startswith(sep): +- # Symlink target is absolute; reset resolved path. +- path = sep +- if maxlinks is None: +- # Mark this symlink as seen but not fully resolved. +- seen[newpath] = None +- # Push the symlink path onto the stack, and signal its specialness +- # by also pushing None. When these entries are popped, we'll +- # record the fully-resolved symlink target in the 'seen' mapping. +- rest.append(newpath) +- rest.append(None) +- # Push the unresolved symlink target parts onto the stack. +- target_parts = target.split(sep)[::-1] +- rest.extend(target_parts) +- part_count += len(target_parts) ++ # An error occurred and was ignored. ++ path = newpath + + return path + +diff --git a/Lib/tarfile.py b/Lib/tarfile.py +index 212b71f6509740..068aa13ed70356 100644 +--- a/Lib/tarfile.py ++++ b/Lib/tarfile.py +@@ -67,7 +67,7 @@ + "DEFAULT_FORMAT", "open","fully_trusted_filter", "data_filter", + "tar_filter", "FilterError", "AbsoluteLinkError", + "OutsideDestinationError", "SpecialFileError", "AbsolutePathError", +- "LinkOutsideDestinationError"] ++ "LinkOutsideDestinationError", "LinkFallbackError"] + + + #--------------------------------------------------------- +@@ -766,10 +766,22 @@ def __init__(self, tarinfo, path): + super().__init__(f'{tarinfo.name!r} would link to {path!r}, ' + + 'which is outside the destination') + ++class LinkFallbackError(FilterError): ++ def __init__(self, tarinfo, path): ++ self.tarinfo = tarinfo ++ self._path = path ++ super().__init__(f'link {tarinfo.name!r} would be extracted as a ' ++ + f'copy of {path!r}, which was rejected') ++ ++# Errors caused by filters -- both "fatal" and "non-fatal" -- that ++# we consider to be issues with the argument, rather than a bug in the ++# filter function ++_FILTER_ERRORS = (FilterError, OSError, ExtractError) ++ + def _get_filtered_attrs(member, dest_path, for_data=True): + new_attrs = {} + name = member.name +- dest_path = os.path.realpath(dest_path) ++ dest_path = os.path.realpath(dest_path, strict=os.path.ALLOW_MISSING) + # Strip leading / (tar's directory separator) from filenames. + # Include os.sep (target OS directory separator) as well. + if name.startswith(('/', os.sep)): +@@ -779,7 +791,8 @@ def _get_filtered_attrs(member, dest_path, for_data=True): + # For example, 'C:/foo' on Windows. + raise AbsolutePathError(member) + # Ensure we stay in the destination +- target_path = os.path.realpath(os.path.join(dest_path, name)) ++ target_path = os.path.realpath(os.path.join(dest_path, name), ++ strict=os.path.ALLOW_MISSING) + if os.path.commonpath([target_path, dest_path]) != dest_path: + raise OutsideDestinationError(member, target_path) + # Limit permissions (no high bits, and go-w) +@@ -817,6 +830,9 @@ def _get_filtered_attrs(member, dest_path, for_data=True): + if member.islnk() or member.issym(): + if os.path.isabs(member.linkname): + raise AbsoluteLinkError(member) ++ normalized = os.path.normpath(member.linkname) ++ if normalized != member.linkname: ++ new_attrs['linkname'] = normalized + if member.issym(): + target_path = os.path.join(dest_path, + os.path.dirname(name), +@@ -824,7 +840,8 @@ def _get_filtered_attrs(member, dest_path, for_data=True): + else: + target_path = os.path.join(dest_path, + member.linkname) +- target_path = os.path.realpath(target_path) ++ target_path = os.path.realpath(target_path, ++ strict=os.path.ALLOW_MISSING) + if os.path.commonpath([target_path, dest_path]) != dest_path: + raise LinkOutsideDestinationError(member, target_path) + return new_attrs +@@ -2386,30 +2403,58 @@ def extractall(self, path=".", members=None, *, numeric_owner=False, + members = self + + for member in members: +- tarinfo = self._get_extract_tarinfo(member, filter_function, path) ++ tarinfo, unfiltered = self._get_extract_tarinfo( ++ member, filter_function, path) + if tarinfo is None: + continue + if tarinfo.isdir(): + # For directories, delay setting attributes until later, + # since permissions can interfere with extraction and + # extracting contents can reset mtime. +- directories.append(tarinfo) ++ directories.append(unfiltered) + self._extract_one(tarinfo, path, set_attrs=not tarinfo.isdir(), +- numeric_owner=numeric_owner) ++ numeric_owner=numeric_owner, ++ filter_function=filter_function) + + # Reverse sort directories. + directories.sort(key=lambda a: a.name, reverse=True) + ++ + # Set correct owner, mtime and filemode on directories. +- for tarinfo in directories: +- dirpath = os.path.join(path, tarinfo.name) ++ for unfiltered in directories: + try: ++ # Need to re-apply any filter, to take the *current* filesystem ++ # state into account. ++ try: ++ tarinfo = filter_function(unfiltered, path) ++ except _FILTER_ERRORS as exc: ++ self._log_no_directory_fixup(unfiltered, repr(exc)) ++ continue ++ if tarinfo is None: ++ self._log_no_directory_fixup(unfiltered, ++ 'excluded by filter') ++ continue ++ dirpath = os.path.join(path, tarinfo.name) ++ try: ++ lstat = os.lstat(dirpath) ++ except FileNotFoundError: ++ self._log_no_directory_fixup(tarinfo, 'missing') ++ continue ++ if not stat.S_ISDIR(lstat.st_mode): ++ # This is no longer a directory; presumably a later ++ # member overwrote the entry. ++ self._log_no_directory_fixup(tarinfo, 'not a directory') ++ continue + self.chown(tarinfo, dirpath, numeric_owner=numeric_owner) + self.utime(tarinfo, dirpath) + self.chmod(tarinfo, dirpath) + except ExtractError as e: + self._handle_nonfatal_error(e) + ++ def _log_no_directory_fixup(self, member, reason): ++ self._dbg(2, "tarfile: Not fixing up directory %r (%s)" % ++ (member.name, reason)) ++ + def extract(self, member, path="", set_attrs=True, *, numeric_owner=False, + filter=None): + """Extract a member from the archive to the current working directory, +@@ -2425,41 +2470,56 @@ def extract(self, member, path="", set_attrs=True, *, numeric_owner=False, + String names of common filters are accepted. + """ + filter_function = self._get_filter_function(filter) +- tarinfo = self._get_extract_tarinfo(member, filter_function, path) ++ tarinfo, unfiltered = self._get_extract_tarinfo( ++ member, filter_function, path) + if tarinfo is not None: + self._extract_one(tarinfo, path, set_attrs, numeric_owner) + + def _get_extract_tarinfo(self, member, filter_function, path): +- """Get filtered TarInfo (or None) from member, which might be a str""" ++ """Get (filtered, unfiltered) TarInfos from *member* ++ ++ *member* might be a string. ++ ++ Return (None, None) if not found. ++ """ ++ + if isinstance(member, str): +- tarinfo = self.getmember(member) ++ unfiltered = self.getmember(member) + else: +- tarinfo = member ++ unfiltered = member + +- unfiltered = tarinfo ++ filtered = None + try: +- tarinfo = filter_function(tarinfo, path) ++ filtered = filter_function(unfiltered, path) + except (OSError, UnicodeEncodeError, FilterError) as e: + self._handle_fatal_error(e) + except ExtractError as e: + self._handle_nonfatal_error(e) +- if tarinfo is None: ++ if filtered is None: + self._dbg(2, "tarfile: Excluded %r" % unfiltered.name) +- return None ++ return None, None ++ + # Prepare the link target for makelink(). +- if tarinfo.islnk(): +- tarinfo = copy.copy(tarinfo) +- tarinfo._link_target = os.path.join(path, tarinfo.linkname) +- return tarinfo ++ if filtered.islnk(): ++ filtered = copy.copy(filtered) ++ filtered._link_target = os.path.join(path, filtered.linkname) ++ return filtered, unfiltered ++ ++ def _extract_one(self, tarinfo, path, set_attrs, numeric_owner, ++ filter_function=None): ++ """Extract from filtered tarinfo to disk. + +- def _extract_one(self, tarinfo, path, set_attrs, numeric_owner): +- """Extract from filtered tarinfo to disk""" ++ filter_function is only used when extracting a *different* ++ member (e.g. as fallback to creating a symlink) ++ """ + self._check("r") + + try: + self._extract_member(tarinfo, os.path.join(path, tarinfo.name), + set_attrs=set_attrs, +- numeric_owner=numeric_owner) ++ numeric_owner=numeric_owner, ++ filter_function=filter_function, ++ extraction_root=path) + except (OSError, UnicodeEncodeError) as e: + self._handle_fatal_error(e) + except ExtractError as e: +@@ -2517,9 +2577,13 @@ def extractfile(self, member): + return None + + def _extract_member(self, tarinfo, targetpath, set_attrs=True, +- numeric_owner=False): +- """Extract the TarInfo object tarinfo to a physical ++ numeric_owner=False, *, filter_function=None, ++ extraction_root=None): ++ """Extract the filtered TarInfo object tarinfo to a physical + file called targetpath. ++ ++ filter_function is only used when extracting a *different* ++ member (e.g. as fallback to creating a symlink) + """ + # Fetch the TarInfo object for the given name + # and build the destination pathname, replacing +@@ -2548,7 +2612,10 @@ def _extract_member(self, tarinfo, targetpath, set_attrs=True, + elif tarinfo.ischr() or tarinfo.isblk(): + self.makedev(tarinfo, targetpath) + elif tarinfo.islnk() or tarinfo.issym(): +- self.makelink(tarinfo, targetpath) ++ self.makelink_with_filter( ++ tarinfo, targetpath, ++ filter_function=filter_function, ++ extraction_root=extraction_root) + elif tarinfo.type not in SUPPORTED_TYPES: + self.makeunknown(tarinfo, targetpath) + else: +@@ -2631,10 +2698,18 @@ def makedev(self, tarinfo, targetpath): + os.makedev(tarinfo.devmajor, tarinfo.devminor)) + + def makelink(self, tarinfo, targetpath): ++ return self.makelink_with_filter(tarinfo, targetpath, None, None) ++ ++ def makelink_with_filter(self, tarinfo, targetpath, ++ filter_function, extraction_root): + """Make a (symbolic) link called targetpath. If it cannot be created + (platform limitation), we try to make a copy of the referenced file + instead of a link. ++ ++ filter_function is only used when extracting a *different* ++ member (e.g. as fallback to creating a link). + """ ++ keyerror_to_extracterror = False + try: + # For systems that support symbolic and hard links. + if tarinfo.issym(): +@@ -2642,18 +2717,38 @@ def makelink(self, tarinfo, targetpath): + # Avoid FileExistsError on following os.symlink. + os.unlink(targetpath) + os.symlink(tarinfo.linkname, targetpath) ++ return + else: + if os.path.exists(tarinfo._link_target): + os.link(tarinfo._link_target, targetpath) +- else: +- self._extract_member(self._find_link_target(tarinfo), +- targetpath) ++ return + except symlink_exception: ++ keyerror_to_extracterror = True ++ ++ try: ++ unfiltered = self._find_link_target(tarinfo) ++ except KeyError: ++ if keyerror_to_extracterror: ++ raise ExtractError( ++ "unable to resolve link inside archive") from None ++ else: ++ raise ++ ++ if filter_function is None: ++ filtered = unfiltered ++ else: ++ if extraction_root is None: ++ raise ExtractError( ++ "makelink_with_filter: if filter_function is not None, " ++ + "extraction_root must also not be None") + try: +- self._extract_member(self._find_link_target(tarinfo), +- targetpath) +- except KeyError: +- raise ExtractError("unable to resolve link inside archive") from None ++ filtered = filter_function(unfiltered, extraction_root) ++ except _FILTER_ERRORS as cause: ++ raise LinkFallbackError(tarinfo, unfiltered.name) from cause ++ if filtered is not None: ++ self._extract_member(filtered, targetpath, ++ filter_function=filter_function, ++ extraction_root=extraction_root) + + def chown(self, tarinfo, targetpath, numeric_owner): + """Set owner of targetpath according to tarinfo. If numeric_owner +diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py +index f83ef225a6e48e..927a0befcc8c13 100644 +--- a/Lib/test/test_ntpath.py ++++ b/Lib/test/test_ntpath.py +@@ -7,7 +7,8 @@ + import unittest + import warnings + from test.support import cpython_only, os_helper +-from test.support import TestFailed, is_emscripten ++from test.support import TestFailed ++from ntpath import ALLOW_MISSING + from test.support.os_helper import FakePath + from test import test_genericpath + from tempfile import TemporaryFile +@@ -77,6 +78,27 @@ def tester(fn, wantResult): + %(str(fn), str(wantResult), repr(gotResult))) + + ++def _parameterize(*parameters): ++ """Simplistic decorator to parametrize a test ++ ++ Runs the decorated test multiple times in subTest, with a value from ++ 'parameters' passed as an extra positional argument. ++ Calls doCleanups() after each run. ++ ++ Not for general use. Intended to avoid indenting for easier backports. ++ ++ See https://discuss.python.org/t/91827 for discussing generalizations. ++ """ ++ def _parametrize_decorator(func): ++ def _parameterized(self, *args, **kwargs): ++ for parameter in parameters: ++ with self.subTest(parameter): ++ func(self, *args, parameter, **kwargs) ++ self.doCleanups() ++ return _parameterized ++ return _parametrize_decorator ++ ++ + class NtpathTestCase(unittest.TestCase): + def assertPathEqual(self, path1, path2): + if path1 == path2 or _norm(path1) == _norm(path2): +@@ -475,6 +497,27 @@ def test_realpath_curdir(self): + tester("ntpath.realpath('.\\.')", expected) + tester("ntpath.realpath('\\'.join(['.'] * 100))", expected) + ++ def test_realpath_curdir_strict(self): ++ expected = ntpath.normpath(os.getcwd()) ++ tester("ntpath.realpath('.', strict=True)", expected) ++ tester("ntpath.realpath('./.', strict=True)", expected) ++ tester("ntpath.realpath('/'.join(['.'] * 100), strict=True)", expected) ++ tester("ntpath.realpath('.\\.', strict=True)", expected) ++ tester("ntpath.realpath('\\'.join(['.'] * 100), strict=True)", expected) ++ ++ def test_realpath_curdir_missing_ok(self): ++ expected = ntpath.normpath(os.getcwd()) ++ tester("ntpath.realpath('.', strict=ALLOW_MISSING)", ++ expected) ++ tester("ntpath.realpath('./.', strict=ALLOW_MISSING)", ++ expected) ++ tester("ntpath.realpath('/'.join(['.'] * 100), strict=ALLOW_MISSING)", ++ expected) ++ tester("ntpath.realpath('.\\.', strict=ALLOW_MISSING)", ++ expected) ++ tester("ntpath.realpath('\\'.join(['.'] * 100), strict=ALLOW_MISSING)", ++ expected) ++ + def test_realpath_pardir(self): + expected = ntpath.normpath(os.getcwd()) + tester("ntpath.realpath('..')", ntpath.dirname(expected)) +@@ -487,24 +530,59 @@ def test_realpath_pardir(self): + tester("ntpath.realpath('\\'.join(['..'] * 50))", + ntpath.splitdrive(expected)[0] + '\\') + ++ def test_realpath_pardir_strict(self): ++ expected = ntpath.normpath(os.getcwd()) ++ tester("ntpath.realpath('..', strict=True)", ntpath.dirname(expected)) ++ tester("ntpath.realpath('../..', strict=True)", ++ ntpath.dirname(ntpath.dirname(expected))) ++ tester("ntpath.realpath('/'.join(['..'] * 50), strict=True)", ++ ntpath.splitdrive(expected)[0] + '\\') ++ tester("ntpath.realpath('..\\..', strict=True)", ++ ntpath.dirname(ntpath.dirname(expected))) ++ tester("ntpath.realpath('\\'.join(['..'] * 50), strict=True)", ++ ntpath.splitdrive(expected)[0] + '\\') ++ ++ def test_realpath_pardir_missing_ok(self): ++ expected = ntpath.normpath(os.getcwd()) ++ tester("ntpath.realpath('..', strict=ALLOW_MISSING)", ++ ntpath.dirname(expected)) ++ tester("ntpath.realpath('../..', strict=ALLOW_MISSING)", ++ ntpath.dirname(ntpath.dirname(expected))) ++ tester("ntpath.realpath('/'.join(['..'] * 50), strict=ALLOW_MISSING)", ++ ntpath.splitdrive(expected)[0] + '\\') ++ tester("ntpath.realpath('..\\..', strict=ALLOW_MISSING)", ++ ntpath.dirname(ntpath.dirname(expected))) ++ tester("ntpath.realpath('\\'.join(['..'] * 50), strict=ALLOW_MISSING)", ++ ntpath.splitdrive(expected)[0] + '\\') ++ + @os_helper.skip_unless_symlink + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') +- def test_realpath_basic(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_basic(self, kwargs): + ABSTFN = ntpath.abspath(os_helper.TESTFN) + open(ABSTFN, "wb").close() + self.addCleanup(os_helper.unlink, ABSTFN) + self.addCleanup(os_helper.unlink, ABSTFN + "1") + + os.symlink(ABSTFN, ABSTFN + "1") +- self.assertPathEqual(ntpath.realpath(ABSTFN + "1"), ABSTFN) +- self.assertPathEqual(ntpath.realpath(os.fsencode(ABSTFN + "1")), ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "1", **kwargs), ABSTFN) ++ self.assertPathEqual(ntpath.realpath(os.fsencode(ABSTFN + "1"), **kwargs), + os.fsencode(ABSTFN)) + + # gh-88013: call ntpath.realpath with binary drive name may raise a + # TypeError. The drive should not exist to reproduce the bug. + drives = {f"{c}:\\" for c in string.ascii_uppercase} - set(os.listdrives()) + d = drives.pop().encode() +- self.assertEqual(ntpath.realpath(d), d) ++ self.assertEqual(ntpath.realpath(d, strict=False), d) ++ ++ # gh-106242: Embedded nulls and non-strict fallback to abspath ++ if kwargs: ++ with self.assertRaises(OSError): ++ ntpath.realpath(os_helper.TESTFN + "\0spam", ++ **kwargs) ++ else: ++ self.assertEqual(ABSTFN + "\0spam", ++ ntpath.realpath(os_helper.TESTFN + "\0spam", **kwargs)) + + @os_helper.skip_unless_symlink + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') +@@ -527,51 +605,66 @@ def test_realpath_invalid_paths(self): + self.assertEqual(realpath(path, strict=False), path) + # gh-106242: Embedded nulls should raise OSError (not ValueError) + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + path = ABSTFNb + b'\x00' + self.assertEqual(realpath(path, strict=False), path) + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + path = ABSTFN + '\\nonexistent\\x\x00' + self.assertEqual(realpath(path, strict=False), path) + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + path = ABSTFNb + b'\\nonexistent\\x\x00' + self.assertEqual(realpath(path, strict=False), path) + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + path = ABSTFN + '\x00\\..' + self.assertEqual(realpath(path, strict=False), os.getcwd()) + self.assertEqual(realpath(path, strict=True), os.getcwd()) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), os.getcwd()) + path = ABSTFNb + b'\x00\\..' + self.assertEqual(realpath(path, strict=False), os.getcwdb()) + self.assertEqual(realpath(path, strict=True), os.getcwdb()) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), os.getcwdb()) + path = ABSTFN + '\\nonexistent\\x\x00\\..' + self.assertEqual(realpath(path, strict=False), ABSTFN + '\\nonexistent') + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), ABSTFN + '\\nonexistent') + path = ABSTFNb + b'\\nonexistent\\x\x00\\..' + self.assertEqual(realpath(path, strict=False), ABSTFNb + b'\\nonexistent') + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), ABSTFNb + b'\\nonexistent') + ++ @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_invalid_unicode_paths(self, kwargs): ++ realpath = ntpath.realpath ++ ABSTFN = ntpath.abspath(os_helper.TESTFN) ++ ABSTFNb = os.fsencode(ABSTFN) + path = ABSTFNb + b'\xff' +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) + path = ABSTFNb + b'\\nonexistent\\\xff' +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) + path = ABSTFNb + b'\xff\\..' +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) + path = ABSTFNb + b'\\nonexistent\\\xff\\..' +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) +- self.assertRaises(UnicodeDecodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) ++ self.assertRaises(UnicodeDecodeError, realpath, path, **kwargs) + + @os_helper.skip_unless_symlink + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') +- def test_realpath_relative(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_relative(self, kwargs): + ABSTFN = ntpath.abspath(os_helper.TESTFN) + open(ABSTFN, "wb").close() + self.addCleanup(os_helper.unlink, ABSTFN) + self.addCleanup(os_helper.unlink, ABSTFN + "1") + + os.symlink(ABSTFN, ntpath.relpath(ABSTFN + "1")) +- self.assertPathEqual(ntpath.realpath(ABSTFN + "1"), ABSTFN) ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "1", **kwargs), ABSTFN) + + @os_helper.skip_unless_symlink + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') +@@ -723,7 +816,62 @@ def test_realpath_symlink_loops_strict(self): + + @os_helper.skip_unless_symlink + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') +- def test_realpath_symlink_prefix(self): ++ def test_realpath_symlink_loops_raise(self): ++ # Symlink loops raise OSError in ALLOW_MISSING mode ++ ABSTFN = ntpath.abspath(os_helper.TESTFN) ++ self.addCleanup(os_helper.unlink, ABSTFN) ++ self.addCleanup(os_helper.unlink, ABSTFN + "1") ++ self.addCleanup(os_helper.unlink, ABSTFN + "2") ++ self.addCleanup(os_helper.unlink, ABSTFN + "y") ++ self.addCleanup(os_helper.unlink, ABSTFN + "c") ++ self.addCleanup(os_helper.unlink, ABSTFN + "a") ++ self.addCleanup(os_helper.unlink, ABSTFN + "x") ++ ++ os.symlink(ABSTFN, ABSTFN) ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN, strict=ALLOW_MISSING) ++ ++ os.symlink(ABSTFN + "1", ABSTFN + "2") ++ os.symlink(ABSTFN + "2", ABSTFN + "1") ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1", ++ strict=ALLOW_MISSING) ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN + "2", ++ strict=ALLOW_MISSING) ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN + "1\\x", ++ strict=ALLOW_MISSING) ++ ++ # Windows eliminates '..' components before resolving links; ++ # realpath is not expected to raise if this removes the loop. ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "1\\.."), ++ ntpath.dirname(ABSTFN)) ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "1\\..\\x"), ++ ntpath.dirname(ABSTFN) + "\\x") ++ ++ os.symlink(ABSTFN + "x", ABSTFN + "y") ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "1\\..\\" ++ + ntpath.basename(ABSTFN) + "y"), ++ ABSTFN + "x") ++ self.assertRaises( ++ OSError, ntpath.realpath, ++ ABSTFN + "1\\..\\" + ntpath.basename(ABSTFN) + "1", ++ strict=ALLOW_MISSING) ++ ++ os.symlink(ntpath.basename(ABSTFN) + "a\\b", ABSTFN + "a") ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN + "a", ++ strict=ALLOW_MISSING) ++ ++ os.symlink("..\\" + ntpath.basename(ntpath.dirname(ABSTFN)) ++ + "\\" + ntpath.basename(ABSTFN) + "c", ABSTFN + "c") ++ self.assertRaises(OSError, ntpath.realpath, ABSTFN + "c", ++ strict=ALLOW_MISSING) ++ ++ # Test using relative path as well. ++ self.assertRaises(OSError, ntpath.realpath, ntpath.basename(ABSTFN), ++ strict=ALLOW_MISSING) ++ ++ @os_helper.skip_unless_symlink ++ @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_symlink_prefix(self, kwargs): + ABSTFN = ntpath.abspath(os_helper.TESTFN) + self.addCleanup(os_helper.unlink, ABSTFN + "3") + self.addCleanup(os_helper.unlink, "\\\\?\\" + ABSTFN + "3.") +@@ -738,9 +886,9 @@ def test_realpath_symlink_prefix(self): + f.write(b'1') + os.symlink("\\\\?\\" + ABSTFN + "3.", ABSTFN + "3.link") + +- self.assertPathEqual(ntpath.realpath(ABSTFN + "3link"), ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "3link", **kwargs), + ABSTFN + "3") +- self.assertPathEqual(ntpath.realpath(ABSTFN + "3.link"), ++ self.assertPathEqual(ntpath.realpath(ABSTFN + "3.link", **kwargs), + "\\\\?\\" + ABSTFN + "3.") + + # Resolved paths should be usable to open target files +@@ -750,14 +898,17 @@ def test_realpath_symlink_prefix(self): + self.assertEqual(f.read(), b'1') + + # When the prefix is included, it is not stripped +- self.assertPathEqual(ntpath.realpath("\\\\?\\" + ABSTFN + "3link"), ++ self.assertPathEqual(ntpath.realpath("\\\\?\\" + ABSTFN + "3link", **kwargs), + "\\\\?\\" + ABSTFN + "3") +- self.assertPathEqual(ntpath.realpath("\\\\?\\" + ABSTFN + "3.link"), ++ self.assertPathEqual(ntpath.realpath("\\\\?\\" + ABSTFN + "3.link", **kwargs), + "\\\\?\\" + ABSTFN + "3.") + + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') + def test_realpath_nul(self): + tester("ntpath.realpath('NUL')", r'\\.\NUL') ++ tester("ntpath.realpath('NUL', strict=False)", r'\\.\NUL') ++ tester("ntpath.realpath('NUL', strict=True)", r'\\.\NUL') ++ tester("ntpath.realpath('NUL', strict=ALLOW_MISSING)", r'\\.\NUL') + + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') + @unittest.skipUnless(HAVE_GETSHORTPATHNAME, 'need _getshortpathname') +@@ -781,12 +932,20 @@ def test_realpath_cwd(self): + + self.assertPathEqual(test_file_long, ntpath.realpath(test_file_short)) + +- with os_helper.change_cwd(test_dir_long): +- self.assertPathEqual(test_file_long, ntpath.realpath("file.txt")) +- with os_helper.change_cwd(test_dir_long.lower()): +- self.assertPathEqual(test_file_long, ntpath.realpath("file.txt")) +- with os_helper.change_cwd(test_dir_short): +- self.assertPathEqual(test_file_long, ntpath.realpath("file.txt")) ++ for kwargs in {}, {'strict': True}, {'strict': ALLOW_MISSING}: ++ with self.subTest(**kwargs): ++ with os_helper.change_cwd(test_dir_long): ++ self.assertPathEqual( ++ test_file_long, ++ ntpath.realpath("file.txt", **kwargs)) ++ with os_helper.change_cwd(test_dir_long.lower()): ++ self.assertPathEqual( ++ test_file_long, ++ ntpath.realpath("file.txt", **kwargs)) ++ with os_helper.change_cwd(test_dir_short): ++ self.assertPathEqual( ++ test_file_long, ++ ntpath.realpath("file.txt", **kwargs)) + + @unittest.skipUnless(HAVE_GETFINALPATHNAME, 'need _getfinalpathname') + def test_realpath_permission(self): +@@ -807,12 +966,15 @@ def test_realpath_permission(self): + # Automatic generation of short names may be disabled on + # NTFS volumes for the sake of performance. + # They're not supported at all on ReFS and exFAT. +- subprocess.run( ++ p = subprocess.run( + # Try to set the short name manually. + ['fsutil.exe', 'file', 'setShortName', test_file, 'LONGFI~1.TXT'], + creationflags=subprocess.DETACHED_PROCESS + ) + ++ if p.returncode: ++ raise unittest.SkipTest('failed to set short name') ++ + try: + self.assertPathEqual(test_file, ntpath.realpath(test_file_short)) + except AssertionError: +diff --git a/Lib/test/test_posixpath.py b/Lib/test/test_posixpath.py +index f3f9895f529470..c45ce6d3ef7820 100644 +--- a/Lib/test/test_posixpath.py ++++ b/Lib/test/test_posixpath.py +@@ -4,7 +4,8 @@ + import random + import sys + import unittest +-from posixpath import realpath, abspath, dirname, basename ++from functools import partial ++from posixpath import realpath, abspath, dirname, basename, ALLOW_MISSING + from test import support + from test import test_genericpath + from test.support import import_helper +@@ -33,6 +34,27 @@ def skip_if_ABSTFN_contains_backslash(test): + msg = "ABSTFN is not a posix path - tests fail" + return [test, unittest.skip(msg)(test)][found_backslash] + ++ ++def _parameterize(*parameters): ++ """Simplistic decorator to parametrize a test ++ ++ Runs the decorated test multiple times in subTest, with a value from ++ 'parameters' passed as an extra positional argument. ++ Does *not* call doCleanups() after each run. ++ ++ Not for general use. Intended to avoid indenting for easier backports. ++ ++ See https://discuss.python.org/t/91827 for discussing generalizations. ++ """ ++ def _parametrize_decorator(func): ++ def _parameterized(self, *args, **kwargs): ++ for parameter in parameters: ++ with self.subTest(parameter): ++ func(self, *args, parameter, **kwargs) ++ return _parameterized ++ return _parametrize_decorator ++ ++ + class PosixPathTest(unittest.TestCase): + + def setUp(self): +@@ -442,32 +464,35 @@ def test_normpath(self): + self.assertEqual(result, expected) + + @skip_if_ABSTFN_contains_backslash +- def test_realpath_curdir(self): +- self.assertEqual(realpath('.'), os.getcwd()) +- self.assertEqual(realpath('./.'), os.getcwd()) +- self.assertEqual(realpath('/'.join(['.'] * 100)), os.getcwd()) ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_curdir(self, kwargs): ++ self.assertEqual(realpath('.', **kwargs), os.getcwd()) ++ self.assertEqual(realpath('./.', **kwargs), os.getcwd()) ++ self.assertEqual(realpath('/'.join(['.'] * 100), **kwargs), os.getcwd()) + +- self.assertEqual(realpath(b'.'), os.getcwdb()) +- self.assertEqual(realpath(b'./.'), os.getcwdb()) +- self.assertEqual(realpath(b'/'.join([b'.'] * 100)), os.getcwdb()) ++ self.assertEqual(realpath(b'.', **kwargs), os.getcwdb()) ++ self.assertEqual(realpath(b'./.', **kwargs), os.getcwdb()) ++ self.assertEqual(realpath(b'/'.join([b'.'] * 100), **kwargs), os.getcwdb()) + + @skip_if_ABSTFN_contains_backslash +- def test_realpath_pardir(self): +- self.assertEqual(realpath('..'), dirname(os.getcwd())) +- self.assertEqual(realpath('../..'), dirname(dirname(os.getcwd()))) +- self.assertEqual(realpath('/'.join(['..'] * 100)), '/') ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_pardir(self, kwargs): ++ self.assertEqual(realpath('..', **kwargs), dirname(os.getcwd())) ++ self.assertEqual(realpath('../..', **kwargs), dirname(dirname(os.getcwd()))) ++ self.assertEqual(realpath('/'.join(['..'] * 100), **kwargs), '/') + +- self.assertEqual(realpath(b'..'), dirname(os.getcwdb())) +- self.assertEqual(realpath(b'../..'), dirname(dirname(os.getcwdb()))) +- self.assertEqual(realpath(b'/'.join([b'..'] * 100)), b'/') ++ self.assertEqual(realpath(b'..', **kwargs), dirname(os.getcwdb())) ++ self.assertEqual(realpath(b'../..', **kwargs), dirname(dirname(os.getcwdb()))) ++ self.assertEqual(realpath(b'/'.join([b'..'] * 100), **kwargs), b'/') + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_basic(self): ++ @_parameterize({}, {'strict': ALLOW_MISSING}) ++ def test_realpath_basic(self, kwargs): + # Basic operation. + try: + os.symlink(ABSTFN+"1", ABSTFN) +- self.assertEqual(realpath(ABSTFN), ABSTFN+"1") ++ self.assertEqual(realpath(ABSTFN, **kwargs), ABSTFN+"1") + finally: + os_helper.unlink(ABSTFN) + +@@ -487,90 +512,115 @@ def test_realpath_invalid_paths(self): + path = '/\x00' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(ValueError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = b'/\x00' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(ValueError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = '/nonexistent/x\x00' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = b'/nonexistent/x\x00' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = '/\x00/..' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(ValueError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = b'/\x00/..' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(ValueError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) ++ + path = '/nonexistent/x\x00/..' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + path = b'/nonexistent/x\x00/..' + self.assertRaises(ValueError, realpath, path, strict=False) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertRaises(ValueError, realpath, path, strict=ALLOW_MISSING) + + path = '/\udfff' + if sys.platform == 'win32': + self.assertEqual(realpath(path, strict=False), path) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), path) + else: + self.assertRaises(UnicodeEncodeError, realpath, path, strict=False) + self.assertRaises(UnicodeEncodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeEncodeError, realpath, path, strict=ALLOW_MISSING) + path = '/nonexistent/\udfff' + if sys.platform == 'win32': + self.assertEqual(realpath(path, strict=False), path) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), path) + else: + self.assertRaises(UnicodeEncodeError, realpath, path, strict=False) ++ self.assertRaises(UnicodeEncodeError, realpath, path, strict=ALLOW_MISSING) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) + path = '/\udfff/..' + if sys.platform == 'win32': + self.assertEqual(realpath(path, strict=False), '/') + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), '/') + else: + self.assertRaises(UnicodeEncodeError, realpath, path, strict=False) + self.assertRaises(UnicodeEncodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeEncodeError, realpath, path, strict=ALLOW_MISSING) + path = '/nonexistent/\udfff/..' + if sys.platform == 'win32': + self.assertEqual(realpath(path, strict=False), '/nonexistent') ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), '/nonexistent') + else: + self.assertRaises(UnicodeEncodeError, realpath, path, strict=False) ++ self.assertRaises(UnicodeEncodeError, realpath, path, strict=ALLOW_MISSING) + self.assertRaises(FileNotFoundError, realpath, path, strict=True) + + path = b'/\xff' + if sys.platform == 'win32': + self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) + self.assertRaises(UnicodeDecodeError, realpath, path, strict=True) ++ self.assertRaises(UnicodeDecodeError, realpath, path, strict=ALLOW_MISSING) + else: + self.assertEqual(realpath(path, strict=False), path) + if support.is_wasi: + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + else: + self.assertRaises(FileNotFoundError, realpath, path, strict=True) ++ self.assertEqual(realpath(path, strict=ALLOW_MISSING), path) + path = b'/nonexistent/\xff' + if sys.platform == 'win32': + self.assertRaises(UnicodeDecodeError, realpath, path, strict=False) ++ self.assertRaises(UnicodeDecodeError, realpath, path, strict=ALLOW_MISSING) + else: + self.assertEqual(realpath(path, strict=False), path) + if support.is_wasi: + self.assertRaises(OSError, realpath, path, strict=True) ++ self.assertRaises(OSError, realpath, path, strict=ALLOW_MISSING) + else: + self.assertRaises(FileNotFoundError, realpath, path, strict=True) + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_relative(self): ++ @_parameterize({}, {'strict': ALLOW_MISSING}) ++ def test_realpath_relative(self, kwargs): + try: + os.symlink(posixpath.relpath(ABSTFN+"1"), ABSTFN) +- self.assertEqual(realpath(ABSTFN), ABSTFN+"1") ++ self.assertEqual(realpath(ABSTFN, **kwargs), ABSTFN+"1") + finally: + os_helper.unlink(ABSTFN) + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_missing_pardir(self): ++ @_parameterize({}, {'strict': ALLOW_MISSING}) ++ def test_realpath_missing_pardir(self, kwargs): + try: + os.symlink(TESTFN + "1", TESTFN) +- self.assertEqual(realpath("nonexistent/../" + TESTFN), ABSTFN + "1") ++ self.assertEqual( ++ realpath("nonexistent/../" + TESTFN, **kwargs), ABSTFN + "1") + finally: + os_helper.unlink(TESTFN) + +@@ -617,37 +667,38 @@ def test_realpath_symlink_loops(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_symlink_loops_strict(self): ++ @_parameterize({'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_symlink_loops_strict(self, kwargs): + # Bug #43757, raise OSError if we get into an infinite symlink loop in +- # strict mode. ++ # the strict modes. + try: + os.symlink(ABSTFN, ABSTFN) +- self.assertRaises(OSError, realpath, ABSTFN, strict=True) ++ self.assertRaises(OSError, realpath, ABSTFN, **kwargs) + + os.symlink(ABSTFN+"1", ABSTFN+"2") + os.symlink(ABSTFN+"2", ABSTFN+"1") +- self.assertRaises(OSError, realpath, ABSTFN+"1", strict=True) +- self.assertRaises(OSError, realpath, ABSTFN+"2", strict=True) ++ self.assertRaises(OSError, realpath, ABSTFN+"1", **kwargs) ++ self.assertRaises(OSError, realpath, ABSTFN+"2", **kwargs) + +- self.assertRaises(OSError, realpath, ABSTFN+"1/x", strict=True) +- self.assertRaises(OSError, realpath, ABSTFN+"1/..", strict=True) +- self.assertRaises(OSError, realpath, ABSTFN+"1/../x", strict=True) ++ self.assertRaises(OSError, realpath, ABSTFN+"1/x", **kwargs) ++ self.assertRaises(OSError, realpath, ABSTFN+"1/..", **kwargs) ++ self.assertRaises(OSError, realpath, ABSTFN+"1/../x", **kwargs) + os.symlink(ABSTFN+"x", ABSTFN+"y") + self.assertRaises(OSError, realpath, +- ABSTFN+"1/../" + basename(ABSTFN) + "y", strict=True) ++ ABSTFN+"1/../" + basename(ABSTFN) + "y", **kwargs) + self.assertRaises(OSError, realpath, +- ABSTFN+"1/../" + basename(ABSTFN) + "1", strict=True) ++ ABSTFN+"1/../" + basename(ABSTFN) + "1", **kwargs) + + os.symlink(basename(ABSTFN) + "a/b", ABSTFN+"a") +- self.assertRaises(OSError, realpath, ABSTFN+"a", strict=True) ++ self.assertRaises(OSError, realpath, ABSTFN+"a", **kwargs) + + os.symlink("../" + basename(dirname(ABSTFN)) + "/" + + basename(ABSTFN) + "c", ABSTFN+"c") +- self.assertRaises(OSError, realpath, ABSTFN+"c", strict=True) ++ self.assertRaises(OSError, realpath, ABSTFN+"c", **kwargs) + + # Test using relative path as well. + with os_helper.change_cwd(dirname(ABSTFN)): +- self.assertRaises(OSError, realpath, basename(ABSTFN), strict=True) ++ self.assertRaises(OSError, realpath, basename(ABSTFN), **kwargs) + finally: + os_helper.unlink(ABSTFN) + os_helper.unlink(ABSTFN+"1") +@@ -658,13 +709,14 @@ def test_realpath_symlink_loops_strict(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_repeated_indirect_symlinks(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_repeated_indirect_symlinks(self, kwargs): + # Issue #6975. + try: + os.mkdir(ABSTFN) + os.symlink('../' + basename(ABSTFN), ABSTFN + '/self') + os.symlink('self/self/self', ABSTFN + '/link') +- self.assertEqual(realpath(ABSTFN + '/link'), ABSTFN) ++ self.assertEqual(realpath(ABSTFN + '/link', **kwargs), ABSTFN) + finally: + os_helper.unlink(ABSTFN + '/self') + os_helper.unlink(ABSTFN + '/link') +@@ -672,14 +724,15 @@ def test_realpath_repeated_indirect_symlinks(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_deep_recursion(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_deep_recursion(self, kwargs): + depth = 10 + try: + os.mkdir(ABSTFN) + for i in range(depth): + os.symlink('/'.join(['%d' % i] * 10), ABSTFN + '/%d' % (i + 1)) + os.symlink('.', ABSTFN + '/0') +- self.assertEqual(realpath(ABSTFN + '/%d' % depth), ABSTFN) ++ self.assertEqual(realpath(ABSTFN + '/%d' % depth, **kwargs), ABSTFN) + + # Test using relative path as well. + with os_helper.change_cwd(ABSTFN): +@@ -691,7 +744,8 @@ def test_realpath_deep_recursion(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_resolve_parents(self): ++ @_parameterize({}, {'strict': ALLOW_MISSING}) ++ def test_realpath_resolve_parents(self, kwargs): + # We also need to resolve any symlinks in the parents of a relative + # path passed to realpath. E.g.: current working directory is + # /usr/doc with 'doc' being a symlink to /usr/share/doc. We call +@@ -702,7 +756,8 @@ def test_realpath_resolve_parents(self): + os.symlink(ABSTFN + "/y", ABSTFN + "/k") + + with os_helper.change_cwd(ABSTFN + "/k"): +- self.assertEqual(realpath("a"), ABSTFN + "/y/a") ++ self.assertEqual(realpath("a", **kwargs), ++ ABSTFN + "/y/a") + finally: + os_helper.unlink(ABSTFN + "/k") + os_helper.rmdir(ABSTFN + "/y") +@@ -710,7 +765,8 @@ def test_realpath_resolve_parents(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_resolve_before_normalizing(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_resolve_before_normalizing(self, kwargs): + # Bug #990669: Symbolic links should be resolved before we + # normalize the path. E.g.: if we have directories 'a', 'k' and 'y' + # in the following hierarchy: +@@ -725,10 +781,10 @@ def test_realpath_resolve_before_normalizing(self): + os.symlink(ABSTFN + "/k/y", ABSTFN + "/link-y") + + # Absolute path. +- self.assertEqual(realpath(ABSTFN + "/link-y/.."), ABSTFN + "/k") ++ self.assertEqual(realpath(ABSTFN + "/link-y/..", **kwargs), ABSTFN + "/k") + # Relative path. + with os_helper.change_cwd(dirname(ABSTFN)): +- self.assertEqual(realpath(basename(ABSTFN) + "/link-y/.."), ++ self.assertEqual(realpath(basename(ABSTFN) + "/link-y/..", **kwargs), + ABSTFN + "/k") + finally: + os_helper.unlink(ABSTFN + "/link-y") +@@ -738,7 +794,8 @@ def test_realpath_resolve_before_normalizing(self): + + @os_helper.skip_unless_symlink + @skip_if_ABSTFN_contains_backslash +- def test_realpath_resolve_first(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_resolve_first(self, kwargs): + # Bug #1213894: The first component of the path, if not absolute, + # must be resolved too. + +@@ -748,8 +805,8 @@ def test_realpath_resolve_first(self): + os.symlink(ABSTFN, ABSTFN + "link") + with os_helper.change_cwd(dirname(ABSTFN)): + base = basename(ABSTFN) +- self.assertEqual(realpath(base + "link"), ABSTFN) +- self.assertEqual(realpath(base + "link/k"), ABSTFN + "/k") ++ self.assertEqual(realpath(base + "link", **kwargs), ABSTFN) ++ self.assertEqual(realpath(base + "link/k", **kwargs), ABSTFN + "/k") + finally: + os_helper.unlink(ABSTFN + "link") + os_helper.rmdir(ABSTFN + "/k") +@@ -767,12 +824,67 @@ def test_realpath_unreadable_symlink(self): + self.assertEqual(realpath(ABSTFN + '/foo'), ABSTFN + '/foo') + self.assertEqual(realpath(ABSTFN + '/../foo'), dirname(ABSTFN) + '/foo') + self.assertEqual(realpath(ABSTFN + '/foo/..'), ABSTFN) +- with self.assertRaises(PermissionError): +- realpath(ABSTFN, strict=True) + finally: + os.chmod(ABSTFN, 0o755, follow_symlinks=False) + os_helper.unlink(ABSTFN) + ++ @os_helper.skip_unless_symlink ++ @skip_if_ABSTFN_contains_backslash ++ @unittest.skipIf(os.chmod not in os.supports_follow_symlinks, "Can't set symlink permissions") ++ @unittest.skipIf(sys.platform != "darwin", "only macOS requires read permission to readlink()") ++ @_parameterize({'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_realpath_unreadable_symlink_strict(self, kwargs): ++ try: ++ os.symlink(ABSTFN+"1", ABSTFN) ++ os.chmod(ABSTFN, 0o000, follow_symlinks=False) ++ with self.assertRaises(PermissionError): ++ realpath(ABSTFN, **kwargs) ++ with self.assertRaises(PermissionError): ++ realpath(ABSTFN + '/foo', **kwargs), ++ with self.assertRaises(PermissionError): ++ realpath(ABSTFN + '/../foo', **kwargs) ++ with self.assertRaises(PermissionError): ++ realpath(ABSTFN + '/foo/..', **kwargs) ++ finally: ++ os.chmod(ABSTFN, 0o755, follow_symlinks=False) ++ os.unlink(ABSTFN) ++ ++ @skip_if_ABSTFN_contains_backslash ++ @os_helper.skip_unless_symlink ++ def test_realpath_unreadable_directory(self): ++ try: ++ os.mkdir(ABSTFN) ++ os.mkdir(ABSTFN + '/k') ++ os.chmod(ABSTFN, 0o000) ++ self.assertEqual(realpath(ABSTFN, strict=False), ABSTFN) ++ self.assertEqual(realpath(ABSTFN, strict=True), ABSTFN) ++ self.assertEqual(realpath(ABSTFN, strict=ALLOW_MISSING), ABSTFN) ++ ++ try: ++ os.stat(ABSTFN) ++ except PermissionError: ++ pass ++ else: ++ self.skipTest('Cannot block permissions') ++ ++ self.assertEqual(realpath(ABSTFN + '/k', strict=False), ++ ABSTFN + '/k') ++ self.assertRaises(PermissionError, realpath, ABSTFN + '/k', ++ strict=True) ++ self.assertRaises(PermissionError, realpath, ABSTFN + '/k', ++ strict=ALLOW_MISSING) ++ ++ self.assertEqual(realpath(ABSTFN + '/missing', strict=False), ++ ABSTFN + '/missing') ++ self.assertRaises(PermissionError, realpath, ABSTFN + '/missing', ++ strict=True) ++ self.assertRaises(PermissionError, realpath, ABSTFN + '/missing', ++ strict=ALLOW_MISSING) ++ finally: ++ os.chmod(ABSTFN, 0o755) ++ os_helper.rmdir(ABSTFN + '/k') ++ os_helper.rmdir(ABSTFN) ++ + @skip_if_ABSTFN_contains_backslash + def test_realpath_nonterminal_file(self): + try: +@@ -780,14 +892,27 @@ def test_realpath_nonterminal_file(self): + f.write('test_posixpath wuz ere') + self.assertEqual(realpath(ABSTFN, strict=False), ABSTFN) + self.assertEqual(realpath(ABSTFN, strict=True), ABSTFN) ++ self.assertEqual(realpath(ABSTFN, strict=ALLOW_MISSING), ABSTFN) ++ + self.assertEqual(realpath(ABSTFN + "/", strict=False), ABSTFN) + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/.", strict=False), ABSTFN) + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/..", strict=False), dirname(ABSTFN)) + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/subdir", strict=False), ABSTFN + "/subdir") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", ++ strict=ALLOW_MISSING) + finally: + os_helper.unlink(ABSTFN) + +@@ -800,14 +925,27 @@ def test_realpath_nonterminal_symlink_to_file(self): + os.symlink(ABSTFN + "1", ABSTFN) + self.assertEqual(realpath(ABSTFN, strict=False), ABSTFN + "1") + self.assertEqual(realpath(ABSTFN, strict=True), ABSTFN + "1") ++ self.assertEqual(realpath(ABSTFN, strict=ALLOW_MISSING), ABSTFN + "1") ++ + self.assertEqual(realpath(ABSTFN + "/", strict=False), ABSTFN + "1") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/.", strict=False), ABSTFN + "1") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/..", strict=False), dirname(ABSTFN)) + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/subdir", strict=False), ABSTFN + "1/subdir") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", ++ strict=ALLOW_MISSING) + finally: + os_helper.unlink(ABSTFN) + os_helper.unlink(ABSTFN + "1") +@@ -822,14 +960,27 @@ def test_realpath_nonterminal_symlink_to_symlinks_to_file(self): + os.symlink(ABSTFN + "1", ABSTFN) + self.assertEqual(realpath(ABSTFN, strict=False), ABSTFN + "2") + self.assertEqual(realpath(ABSTFN, strict=True), ABSTFN + "2") ++ self.assertEqual(realpath(ABSTFN, strict=True), ABSTFN + "2") ++ + self.assertEqual(realpath(ABSTFN + "/", strict=False), ABSTFN + "2") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/.", strict=False), ABSTFN + "2") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/.", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/..", strict=False), dirname(ABSTFN)) + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/..", ++ strict=ALLOW_MISSING) ++ + self.assertEqual(realpath(ABSTFN + "/subdir", strict=False), ABSTFN + "2/subdir") + self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", strict=True) ++ self.assertRaises(NotADirectoryError, realpath, ABSTFN + "/subdir", ++ strict=ALLOW_MISSING) + finally: + os_helper.unlink(ABSTFN) + os_helper.unlink(ABSTFN + "1") +@@ -1017,9 +1168,12 @@ def test_path_normpath(self): + def test_path_abspath(self): + self.assertPathEqual(self.path.abspath) + +- def test_path_realpath(self): ++ @_parameterize({}, {'strict': True}, {'strict': ALLOW_MISSING}) ++ def test_path_realpath(self, kwargs): + self.assertPathEqual(self.path.realpath) + ++ self.assertPathEqual(partial(self.path.realpath, **kwargs)) ++ + def test_path_relpath(self): + self.assertPathEqual(self.path.relpath) + +diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py +index cf218a2bf14369..7055e1ed147a9e 100644 +--- a/Lib/test/test_tarfile.py ++++ b/Lib/test/test_tarfile.py +@@ -2715,6 +2715,31 @@ def test_useful_error_message_when_modules_missing(self): + str(excinfo.exception), + ) + ++ @unittest.skipUnless(os_helper.can_symlink(), 'requires symlink support') ++ @unittest.skipUnless(hasattr(os, 'chmod'), "missing os.chmod") ++ @unittest.mock.patch('os.chmod') ++ def test_deferred_directory_attributes_update(self, mock_chmod): ++ # Regression test for gh-127987: setting attributes on arbitrary files ++ tempdir = os.path.join(TEMPDIR, 'test127987') ++ def mock_chmod_side_effect(path, mode, **kwargs): ++ target_path = os.path.realpath(path) ++ if os.path.commonpath([target_path, tempdir]) != tempdir: ++ raise Exception("should not try to chmod anything outside the destination", target_path) ++ mock_chmod.side_effect = mock_chmod_side_effect ++ ++ outside_tree_dir = os.path.join(TEMPDIR, 'outside_tree_dir') ++ with ArchiveMaker() as arc: ++ arc.add('x', symlink_to='.') ++ arc.add('x', type=tarfile.DIRTYPE, mode='?rwsrwsrwt') ++ arc.add('x', symlink_to=outside_tree_dir) ++ ++ os.makedirs(outside_tree_dir) ++ try: ++ arc.open().extractall(path=tempdir, filter='tar') ++ finally: ++ os_helper.rmtree(outside_tree_dir) ++ os_helper.rmtree(tempdir) ++ + + class CommandLineTest(unittest.TestCase): + +@@ -3275,6 +3300,10 @@ def check_files_present(self, directory): + got_paths = set( + p.relative_to(directory) + for p in pathlib.Path(directory).glob('**/*')) ++ if self.extraction_filter in (None, 'data'): ++ # The 'data' filter is expected to reject special files ++ for path in 'ustar/fifotype', 'ustar/blktype', 'ustar/chrtype': ++ got_paths.discard(pathlib.Path(path)) + self.assertEqual(self.control_paths, got_paths) + + @contextmanager +@@ -3504,12 +3533,28 @@ def __exit__(self, *exc): + self.bio = None + + def add(self, name, *, type=None, symlink_to=None, hardlink_to=None, +- mode=None, size=None, **kwargs): +- """Add a member to the test archive. Call within `with`.""" ++ mode=None, size=None, content=None, **kwargs): ++ """Add a member to the test archive. Call within `with`. ++ ++ Provides many shortcuts: ++ - default `type` is based on symlink_to, hardlink_to, and trailing `/` ++ in name (which is stripped) ++ - size & content defaults are based on each other ++ - content can be str or bytes ++ - mode should be textual ('-rwxrwxrwx') ++ ++ (add more! this is unstable internal test-only API) ++ """ + name = str(name) + tarinfo = tarfile.TarInfo(name).replace(**kwargs) ++ if content is not None: ++ if isinstance(content, str): ++ content = content.encode() ++ size = len(content) + if size is not None: + tarinfo.size = size ++ if content is None: ++ content = bytes(tarinfo.size) + if mode: + tarinfo.mode = _filemode_to_int(mode) + if symlink_to is not None: +@@ -3523,7 +3568,7 @@ def add(self, name, *, type=None, symlink_to=None, hardlink_to=None, + if type is not None: + tarinfo.type = type + if tarinfo.isreg(): +- fileobj = io.BytesIO(bytes(tarinfo.size)) ++ fileobj = io.BytesIO(content) + else: + fileobj = None + self.tar_w.addfile(tarinfo, fileobj) +@@ -3557,7 +3602,7 @@ class TestExtractionFilters(unittest.TestCase): + destdir = outerdir / 'dest' + + @contextmanager +- def check_context(self, tar, filter): ++ def check_context(self, tar, filter, *, check_flag=True): + """Extracts `tar` to `self.destdir` and allows checking the result + + If an error occurs, it must be checked using `expect_exception` +@@ -3566,27 +3611,40 @@ def check_context(self, tar, filter): + except the destination directory itself and parent directories of + other files. + When checking directories, do so before their contents. ++ ++ A file called 'flag' is made in outerdir (i.e. outside destdir) ++ before extraction; it should not be altered nor should its contents ++ be read/copied. + """ + with os_helper.temp_dir(self.outerdir): ++ flag_path = self.outerdir / 'flag' ++ flag_path.write_text('capture me') + try: + tar.extractall(self.destdir, filter=filter) + except Exception as exc: + self.raised_exception = exc ++ self.reraise_exception = True + self.expected_paths = set() + else: + self.raised_exception = None ++ self.reraise_exception = False + self.expected_paths = set(self.outerdir.glob('**/*')) + self.expected_paths.discard(self.destdir) ++ self.expected_paths.discard(flag_path) + try: +- yield ++ yield self + finally: + tar.close() +- if self.raised_exception: ++ if self.reraise_exception: + raise self.raised_exception + self.assertEqual(self.expected_paths, set()) ++ if check_flag: ++ self.assertEqual(flag_path.read_text(), 'capture me') ++ else: ++ assert filter == 'fully_trusted' + + def expect_file(self, name, type=None, symlink_to=None, mode=None, +- size=None): ++ size=None, content=None): + """Check a single file. See check_context.""" + if self.raised_exception: + raise self.raised_exception +@@ -3605,26 +3663,45 @@ def expect_file(self, name, type=None, symlink_to=None, mode=None, + # The symlink might be the same (textually) as what we expect, + # but some systems change the link to an equivalent path, so + # we fall back to samefile(). +- if expected != got: +- self.assertTrue(got.samefile(expected)) ++ try: ++ if expected != got: ++ self.assertTrue(got.samefile(expected)) ++ except Exception as e: ++ # attach a note, so it's shown even if `samefile` fails ++ e.add_note(f'{expected=}, {got=}') ++ raise + elif type == tarfile.REGTYPE or type is None: + self.assertTrue(path.is_file()) + elif type == tarfile.DIRTYPE: + self.assertTrue(path.is_dir()) + elif type == tarfile.FIFOTYPE: + self.assertTrue(path.is_fifo()) ++ elif type == tarfile.SYMTYPE: ++ self.assertTrue(path.is_symlink()) + else: + raise NotImplementedError(type) + if size is not None: + self.assertEqual(path.stat().st_size, size) ++ if content is not None: ++ self.assertEqual(path.read_text(), content) + for parent in path.parents: + self.expected_paths.discard(parent) + ++ def expect_any_tree(self, name): ++ """Check a directory; forget about its contents.""" ++ tree_path = (self.destdir / name).resolve() ++ self.expect_file(tree_path, type=tarfile.DIRTYPE) ++ self.expected_paths = { ++ p for p in self.expected_paths ++ if tree_path not in p.parents ++ } ++ + def expect_exception(self, exc_type, message_re='.'): + with self.assertRaisesRegex(exc_type, message_re): + if self.raised_exception is not None: + raise self.raised_exception +- self.raised_exception = None ++ self.reraise_exception = False ++ return self.raised_exception + + def test_benign_file(self): + with ArchiveMaker() as arc: +@@ -3709,6 +3786,80 @@ def test_parent_symlink(self): + with self.check_context(arc.open(), 'data'): + self.expect_file('parent/evil') + ++ @symlink_test ++ @os_helper.skip_unless_symlink ++ def test_realpath_limit_attack(self): ++ # (CVE-2025-4517) ++ ++ with ArchiveMaker() as arc: ++ # populate the symlinks and dirs that expand in os.path.realpath() ++ # The component length is chosen so that in common cases, the unexpanded ++ # path fits in PATH_MAX, but it overflows when the final symlink ++ # is expanded ++ steps = "abcdefghijklmnop" ++ if sys.platform == 'win32': ++ component = 'd' * 25 ++ elif 'PC_PATH_MAX' in os.pathconf_names: ++ max_path_len = os.pathconf(self.outerdir.parent, "PC_PATH_MAX") ++ path_sep_len = 1 ++ dest_len = len(str(self.destdir)) + path_sep_len ++ component_len = (max_path_len - dest_len) // (len(steps) + path_sep_len) ++ component = 'd' * component_len ++ else: ++ raise NotImplementedError("Need to guess component length for {sys.platform}") ++ path = "" ++ step_path = "" ++ for i in steps: ++ arc.add(os.path.join(path, component), type=tarfile.DIRTYPE, ++ mode='drwxrwxrwx') ++ arc.add(os.path.join(path, i), symlink_to=component) ++ path = os.path.join(path, component) ++ step_path = os.path.join(step_path, i) ++ # create the final symlink that exceeds PATH_MAX and simply points ++ # to the top dir. ++ # this link will never be expanded by ++ # os.path.realpath(strict=False), nor anything after it. ++ linkpath = os.path.join(*steps, "l"*254) ++ parent_segments = [".."] * len(steps) ++ arc.add(linkpath, symlink_to=os.path.join(*parent_segments)) ++ # make a symlink outside to keep the tar command happy ++ arc.add("escape", symlink_to=os.path.join(linkpath, "..")) ++ # use the symlinks above, that are not checked, to create a hardlink ++ # to a file outside of the destination path ++ arc.add("flaglink", hardlink_to=os.path.join("escape", "flag")) ++ # now that we have the hardlink we can overwrite the file ++ arc.add("flaglink", content='overwrite') ++ # we can also create new files as well! ++ arc.add("escape/newfile", content='new') ++ ++ with (self.subTest('fully_trusted'), ++ self.check_context(arc.open(), filter='fully_trusted', ++ check_flag=False)): ++ if sys.platform == 'win32': ++ self.expect_exception((FileNotFoundError, FileExistsError)) ++ elif self.raised_exception: ++ # Cannot symlink/hardlink: tarfile falls back to getmember() ++ self.expect_exception(KeyError) ++ # Otherwise, this block should never enter. ++ else: ++ self.expect_any_tree(component) ++ self.expect_file('flaglink', content='overwrite') ++ self.expect_file('../newfile', content='new') ++ self.expect_file('escape', type=tarfile.SYMTYPE) ++ self.expect_file('a', symlink_to=component) ++ ++ for filter in 'tar', 'data': ++ with self.subTest(filter), self.check_context(arc.open(), filter=filter): ++ exc = self.expect_exception((OSError, KeyError)) ++ if isinstance(exc, OSError): ++ if sys.platform == 'win32': ++ # 3: ERROR_PATH_NOT_FOUND ++ # 5: ERROR_ACCESS_DENIED ++ # 206: ERROR_FILENAME_EXCED_RANGE ++ self.assertIn(exc.winerror, (3, 5, 206)) ++ else: ++ self.assertEqual(exc.errno, errno.ENAMETOOLONG) ++ + @symlink_test + def test_parent_symlink2(self): + # Test interplaying symlinks +@@ -3931,8 +4082,8 @@ def test_chains(self): + arc.add('symlink2', symlink_to=os.path.join( + 'linkdir', 'hardlink2')) + arc.add('targetdir/target', size=3) +- arc.add('linkdir/hardlink', hardlink_to='targetdir/target') +- arc.add('linkdir/hardlink2', hardlink_to='linkdir/symlink') ++ arc.add('linkdir/hardlink', hardlink_to=os.path.join('targetdir', 'target')) ++ arc.add('linkdir/hardlink2', hardlink_to=os.path.join('linkdir', 'symlink')) + + for filter in 'tar', 'data', 'fully_trusted': + with self.check_context(arc.open(), filter): +@@ -3948,6 +4099,129 @@ def test_chains(self): + self.expect_file('linkdir/symlink', size=3) + self.expect_file('symlink2', size=3) + ++ @symlink_test ++ def test_sneaky_hardlink_fallback(self): ++ # (CVE-2025-4330) ++ # Test that when hardlink extraction falls back to extracting members ++ # from the archive, the extracted member is (re-)filtered. ++ with ArchiveMaker() as arc: ++ # Create a directory structure so the c/escape symlink stays ++ # inside the path ++ arc.add("a/t/dummy") ++ # Create b/ directory ++ arc.add("b/") ++ # Point "c" to the bottom of the tree in "a" ++ arc.add("c", symlink_to=os.path.join("a", "t")) ++ # link to non-existant location under "a" ++ arc.add("c/escape", symlink_to=os.path.join("..", "..", ++ "link_here")) ++ # Move "c" to point to "b" ("c/escape" no longer exists) ++ arc.add("c", symlink_to="b") ++ # Attempt to create a hard link to "c/escape". Since it doesn't ++ # exist it will attempt to extract "cescape" but at "boom". ++ arc.add("boom", hardlink_to=os.path.join("c", "escape")) ++ ++ with self.check_context(arc.open(), 'data'): ++ if not os_helper.can_symlink(): ++ # When 'c/escape' is extracted, 'c' is a regular ++ # directory, and 'c/escape' *would* point outside ++ # the destination if symlinks were allowed. ++ self.expect_exception( ++ tarfile.LinkOutsideDestinationError) ++ elif sys.platform == "win32": ++ # On Windows, 'c/escape' points outside the destination ++ self.expect_exception(tarfile.LinkOutsideDestinationError) ++ else: ++ e = self.expect_exception( ++ tarfile.LinkFallbackError, ++ "link 'boom' would be extracted as a copy of " ++ + "'c/escape', which was rejected") ++ self.assertIsInstance(e.__cause__, ++ tarfile.LinkOutsideDestinationError) ++ for filter in 'tar', 'fully_trusted': ++ with self.subTest(filter), self.check_context(arc.open(), filter): ++ if not os_helper.can_symlink(): ++ self.expect_file("a/t/dummy") ++ self.expect_file("b/") ++ self.expect_file("c/") ++ else: ++ self.expect_file("a/t/dummy") ++ self.expect_file("b/") ++ self.expect_file("a/t/escape", symlink_to='../../link_here') ++ self.expect_file("boom", symlink_to='../../link_here') ++ self.expect_file("c", symlink_to='b') ++ ++ @symlink_test ++ def test_exfiltration_via_symlink(self): ++ # (CVE-2025-4138) ++ # Test changing symlinks that result in a symlink pointing outside ++ # the extraction directory, unless prevented by 'data' filter's ++ # normalization. ++ with ArchiveMaker() as arc: ++ arc.add("escape", symlink_to=os.path.join('link', 'link', '..', '..', 'link-here')) ++ arc.add("link", symlink_to='./') ++ ++ for filter in 'tar', 'data', 'fully_trusted': ++ with self.check_context(arc.open(), filter): ++ if os_helper.can_symlink(): ++ self.expect_file("link", symlink_to='./') ++ if filter == 'data': ++ self.expect_file("escape", symlink_to='link-here') ++ else: ++ self.expect_file("escape", ++ symlink_to='link/link/../../link-here') ++ else: ++ # Nothing is extracted. ++ pass ++ ++ @symlink_test ++ def test_chmod_outside_dir(self): ++ # (CVE-2024-12718) ++ # Test that members used for delayed updates of directory metadata ++ # are (re-)filtered. ++ with ArchiveMaker() as arc: ++ # "pwn" is a veeeery innocent symlink: ++ arc.add("a/pwn", symlink_to='.') ++ # But now "pwn" is also a directory, so it's scheduled to have its ++ # metadata updated later: ++ arc.add("a/pwn/", mode='drwxrwxrwx') ++ # Oops, "pwn" is not so innocent any more: ++ arc.add("a/pwn", symlink_to='x/../') ++ # Newly created symlink points to the dest dir, ++ # so it's OK for the "data" filter. ++ arc.add('a/x', symlink_to=('../')) ++ # But now "pwn" points outside the dest dir ++ ++ for filter in 'tar', 'data', 'fully_trusted': ++ with self.check_context(arc.open(), filter) as cc: ++ if not os_helper.can_symlink(): ++ self.expect_file("a/pwn/") ++ elif filter == 'data': ++ self.expect_file("a/x", symlink_to='../') ++ self.expect_file("a/pwn", symlink_to='.') ++ else: ++ self.expect_file("a/x", symlink_to='../') ++ self.expect_file("a/pwn", symlink_to='x/../') ++ if sys.platform != "win32": ++ st_mode = cc.outerdir.stat().st_mode ++ self.assertNotEqual(st_mode & 0o777, 0o777) ++ ++ def test_link_fallback_normalizes(self): ++ # Make sure hardlink fallbacks work for non-normalized paths for all ++ # filters ++ with ArchiveMaker() as arc: ++ arc.add("dir/") ++ arc.add("dir/../afile") ++ arc.add("link1", hardlink_to='dir/../afile') ++ arc.add("link2", hardlink_to='dir/../dir/../afile') ++ ++ for filter in 'tar', 'data', 'fully_trusted': ++ with self.check_context(arc.open(), filter) as cc: ++ self.expect_file("dir/") ++ self.expect_file("afile") ++ self.expect_file("link1") ++ self.expect_file("link2") ++ + def test_modes(self): + # Test how file modes are extracted + # (Note that the modes are ignored on platforms without working chmod) +@@ -4072,7 +4346,7 @@ def test_tar_filter(self): + # The 'tar' filter returns TarInfo objects with the same name/type. + # (It can also fail for particularly "evil" input, but we don't have + # that in the test archive.) +- with tarfile.TarFile.open(tarname) as tar: ++ with tarfile.TarFile.open(tarname, encoding="iso8859-1") as tar: + for tarinfo in tar.getmembers(): + try: + filtered = tarfile.tar_filter(tarinfo, '') +@@ -4084,7 +4358,7 @@ def test_tar_filter(self): + def test_data_filter(self): + # The 'data' filter either raises, or returns TarInfo with the same + # name/type. +- with tarfile.TarFile.open(tarname) as tar: ++ with tarfile.TarFile.open(tarname, encoding="iso8859-1") as tar: + for tarinfo in tar.getmembers(): + try: + filtered = tarfile.data_filter(tarinfo, '') +@@ -4242,13 +4516,13 @@ def valueerror_filter(tarinfo, path): + # If errorlevel is 0, errors affected by errorlevel are ignored + + with self.check_context(arc.open(errorlevel=0), extracterror_filter): +- self.expect_file('file') ++ pass + + with self.check_context(arc.open(errorlevel=0), filtererror_filter): +- self.expect_file('file') ++ pass + + with self.check_context(arc.open(errorlevel=0), oserror_filter): +- self.expect_file('file') ++ pass + + with self.check_context(arc.open(errorlevel=0), tarerror_filter): + self.expect_exception(tarfile.TarError) +@@ -4259,7 +4533,7 @@ def valueerror_filter(tarinfo, path): + # If 1, all fatal errors are raised + + with self.check_context(arc.open(errorlevel=1), extracterror_filter): +- self.expect_file('file') ++ pass + + with self.check_context(arc.open(errorlevel=1), filtererror_filter): + self.expect_exception(tarfile.FilterError) +diff --git a/Misc/NEWS.d/next/Security/2025-06-02-11-32-23.gh-issue-135034.RLGjbp.rst b/Misc/NEWS.d/next/Security/2025-06-02-11-32-23.gh-issue-135034.RLGjbp.rst +new file mode 100644 +index 00000000000000..08a0087e203671 +--- /dev/null ++++ b/Misc/NEWS.d/next/Security/2025-06-02-11-32-23.gh-issue-135034.RLGjbp.rst +@@ -0,0 +1,6 @@ ++Fixes multiple issues that allowed ``tarfile`` extraction filters ++(``filter="data"`` and ``filter="tar"``) to be bypassed using crafted ++symlinks and hard links. ++ ++Addresses :cve:`2024-12718`, :cve:`2025-4138`, :cve:`2025-4330`, and :cve:`2025-4517`. ++ diff --git a/pkgs/development/interpreters/python/cpython/default.nix b/pkgs/development/interpreters/python/cpython/default.nix index 52b0a3ea4eb4..216c7d064fb5 100644 --- a/pkgs/development/interpreters/python/cpython/default.nix +++ b/pkgs/development/interpreters/python/cpython/default.nix @@ -339,6 +339,9 @@ stdenv.mkDerivation (finalAttrs: { ++ optionals (pythonAtLeast "3.13") [ ./3.13/virtualenv-permissions.patch ] + ++ optionals (pythonAtLeast "3.14") [ + ./3.14/CVE-2025-4517.patch + ] ++ optionals mimetypesSupport [ # Make the mimetypes module refer to the right file ./mimetypes.patch