MSVSphere Packaging Team
4 months ago
parent
fe280c0944
commit
1caf821acc
@ -0,0 +1,345 @@
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From 7a25b2f511054dd2011308275bb24e914e1977af Mon Sep 17 00:00:00 2001
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From: Petr Viktorin <encukou@gmail.com>
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Date: Tue, 6 Aug 2024 19:07:19 +0200
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Subject: [PATCH] gh-121650: Encode newlines in headers, and verify headers are
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sound (GH-122233) (#122599)
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* gh-121650: Encode newlines in headers, and verify headers are sound (GH-122233)
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- Encode header parts that contain newlines
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Per RFC 2047:
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> [...] these encoding schemes allow the
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> encoding of arbitrary octet values, mail readers that implement this
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> decoding should also ensure that display of the decoded data on the
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> recipient's terminal will not cause unwanted side-effects
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It seems that the "quoted-word" scheme is a valid way to include
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a newline character in a header value, just like we already allow
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undecodable bytes or control characters.
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They do need to be properly quoted when serialized to text, though.
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- Verify that email headers are well-formed
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This should fail for custom fold() implementations that aren't careful
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about newlines.
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Co-authored-by: Bas Bloemsaat <bas@bloemsaat.org>
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Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
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(cherry picked from commit 097633981879b3c9de9a1dd120d3aa585ecc2384)
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* Document changes as made in 3.12.5
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---
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Doc/library/email.errors.rst | 7 +++
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Doc/library/email.policy.rst | 18 ++++++
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Lib/email/_header_value_parser.py | 12 +++-
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Lib/email/_policybase.py | 8 +++
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Lib/email/errors.py | 4 ++
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Lib/email/generator.py | 13 +++-
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Lib/test/test_email/test_generator.py | 62 +++++++++++++++++++
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Lib/test/test_email/test_policy.py | 26 ++++++++
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...-07-27-16-10-41.gh-issue-121650.nf6oc9.rst | 5 ++
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9 files changed, 151 insertions(+), 4 deletions(-)
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create mode 100644 Misc/NEWS.d/next/Library/2024-07-27-16-10-41.gh-issue-121650.nf6oc9.rst
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diff --git a/Doc/library/email.errors.rst b/Doc/library/email.errors.rst
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index 56aea65..27b0481 100644
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--- a/Doc/library/email.errors.rst
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+++ b/Doc/library/email.errors.rst
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@@ -58,6 +58,13 @@ The following exception classes are defined in the :mod:`email.errors` module:
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:class:`~email.mime.nonmultipart.MIMENonMultipart` (e.g.
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:class:`~email.mime.image.MIMEImage`).
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+
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+.. exception:: HeaderWriteError()
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+
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+ Raised when an error occurs when the :mod:`~email.generator` outputs
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+ headers.
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+
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+
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.. exception:: MessageDefect()
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This is the base class for all defects found when parsing email messages.
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diff --git a/Doc/library/email.policy.rst b/Doc/library/email.policy.rst
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index fd47dd0..6ec6e4d 100644
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--- a/Doc/library/email.policy.rst
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+++ b/Doc/library/email.policy.rst
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@@ -230,6 +230,24 @@ added matters. To illustrate::
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.. versionadded:: 3.6
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+
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+ .. attribute:: verify_generated_headers
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+
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+ If ``True`` (the default), the generator will raise
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+ :exc:`~email.errors.HeaderWriteError` instead of writing a header
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+ that is improperly folded or delimited, such that it would
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+ be parsed as multiple headers or joined with adjacent data.
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+ Such headers can be generated by custom header classes or bugs
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+ in the ``email`` module.
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+
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+ As it's a security feature, this defaults to ``True`` even in the
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+ :class:`~email.policy.Compat32` policy.
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+ For backwards compatible, but unsafe, behavior, it must be set to
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+ ``False`` explicitly.
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+
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+ .. versionadded:: 3.12.5
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+
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+
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The following :class:`Policy` method is intended to be called by code using
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the email library to create policy instances with custom settings:
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diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py
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index 0d6bd81..362edc5 100644
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--- a/Lib/email/_header_value_parser.py
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+++ b/Lib/email/_header_value_parser.py
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@@ -92,6 +92,8 @@ TOKEN_ENDS = TSPECIALS | WSP
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ASPECIALS = TSPECIALS | set("*'%")
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ATTRIBUTE_ENDS = ASPECIALS | WSP
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EXTENDED_ATTRIBUTE_ENDS = ATTRIBUTE_ENDS - set('%')
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+NLSET = {'\n', '\r'}
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+SPECIALSNL = SPECIALS | NLSET
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def quote_string(value):
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return '"'+str(value).replace('\\', '\\\\').replace('"', r'\"')+'"'
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@@ -2776,9 +2778,13 @@ def _refold_parse_tree(parse_tree, *, policy):
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wrap_as_ew_blocked -= 1
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continue
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tstr = str(part)
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- if part.token_type == 'ptext' and set(tstr) & SPECIALS:
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- # Encode if tstr contains special characters.
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- want_encoding = True
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+ if not want_encoding:
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+ if part.token_type == 'ptext':
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+ # Encode if tstr contains special characters.
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+ want_encoding = not SPECIALSNL.isdisjoint(tstr)
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+ else:
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+ # Encode if tstr contains newlines.
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+ want_encoding = not NLSET.isdisjoint(tstr)
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try:
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tstr.encode(encoding)
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charset = encoding
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diff --git a/Lib/email/_policybase.py b/Lib/email/_policybase.py
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index c9cbadd..d1f4821 100644
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--- a/Lib/email/_policybase.py
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+++ b/Lib/email/_policybase.py
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@@ -157,6 +157,13 @@ class Policy(_PolicyBase, metaclass=abc.ABCMeta):
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message_factory -- the class to use to create new message objects.
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If the value is None, the default is Message.
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+ verify_generated_headers
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+ -- if true, the generator verifies that each header
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+ they are properly folded, so that a parser won't
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+ treat it as multiple headers, start-of-body, or
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+ part of another header.
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+ This is a check against custom Header & fold()
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+ implementations.
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"""
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raise_on_defect = False
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@@ -165,6 +172,7 @@ class Policy(_PolicyBase, metaclass=abc.ABCMeta):
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max_line_length = 78
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mangle_from_ = False
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message_factory = None
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+ verify_generated_headers = True
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def handle_defect(self, obj, defect):
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"""Based on policy, either raise defect or call register_defect.
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diff --git a/Lib/email/errors.py b/Lib/email/errors.py
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index 3ad0056..02aa5ec 100644
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--- a/Lib/email/errors.py
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+++ b/Lib/email/errors.py
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@@ -29,6 +29,10 @@ class CharsetError(MessageError):
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"""An illegal charset was given."""
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+class HeaderWriteError(MessageError):
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+ """Error while writing headers."""
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+
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+
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# These are parsing defects which the parser was able to work around.
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class MessageDefect(ValueError):
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"""Base class for a message defect."""
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diff --git a/Lib/email/generator.py b/Lib/email/generator.py
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index 7ccbe10..ea87ad2 100644
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--- a/Lib/email/generator.py
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+++ b/Lib/email/generator.py
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@@ -14,12 +14,14 @@ import random
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from copy import deepcopy
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from io import StringIO, BytesIO
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from email.utils import _has_surrogates
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+from email.errors import HeaderWriteError
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UNDERSCORE = '_'
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NL = '\n' # XXX: no longer used by the code below.
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NLCRE = re.compile(r'\r\n|\r|\n')
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fcre = re.compile(r'^From ', re.MULTILINE)
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+NEWLINE_WITHOUT_FWSP = re.compile(r'\r\n[^ \t]|\r[^ \n\t]|\n[^ \t]')
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class Generator:
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@@ -222,7 +224,16 @@ class Generator:
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def _write_headers(self, msg):
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for h, v in msg.raw_items():
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- self.write(self.policy.fold(h, v))
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+ folded = self.policy.fold(h, v)
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+ if self.policy.verify_generated_headers:
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+ linesep = self.policy.linesep
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+ if not folded.endswith(self.policy.linesep):
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+ raise HeaderWriteError(
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+ f'folded header does not end with {linesep!r}: {folded!r}')
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+ if NEWLINE_WITHOUT_FWSP.search(folded.removesuffix(linesep)):
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+ raise HeaderWriteError(
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+ f'folded header contains newline: {folded!r}')
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+ self.write(folded)
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# A blank line always separates headers from body
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self.write(self._NL)
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diff --git a/Lib/test/test_email/test_generator.py b/Lib/test/test_email/test_generator.py
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index 89e7ede..d29400f 100644
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--- a/Lib/test/test_email/test_generator.py
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+++ b/Lib/test/test_email/test_generator.py
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@@ -6,6 +6,7 @@ from email.message import EmailMessage
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from email.generator import Generator, BytesGenerator
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from email.headerregistry import Address
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from email import policy
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+import email.errors
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from test.test_email import TestEmailBase, parameterize
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@@ -216,6 +217,44 @@ class TestGeneratorBase:
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g.flatten(msg)
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self.assertEqual(s.getvalue(), self.typ(expected))
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+ def test_keep_encoded_newlines(self):
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+ msg = self.msgmaker(self.typ(textwrap.dedent("""\
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+ To: nobody
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+ Subject: Bad subject=?UTF-8?Q?=0A?=Bcc: injection@example.com
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+
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+ None
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+ """)))
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+ expected = textwrap.dedent("""\
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+ To: nobody
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+ Subject: Bad subject=?UTF-8?Q?=0A?=Bcc: injection@example.com
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+
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+ None
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+ """)
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+ s = self.ioclass()
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+ g = self.genclass(s, policy=self.policy.clone(max_line_length=80))
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+ g.flatten(msg)
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+ self.assertEqual(s.getvalue(), self.typ(expected))
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+
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+ def test_keep_long_encoded_newlines(self):
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+ msg = self.msgmaker(self.typ(textwrap.dedent("""\
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+ To: nobody
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+ Subject: Bad subject=?UTF-8?Q?=0A?=Bcc: injection@example.com
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+
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+ None
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+ """)))
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+ expected = textwrap.dedent("""\
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+ To: nobody
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+ Subject: Bad subject
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+ =?utf-8?q?=0A?=Bcc:
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+ injection@example.com
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+
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+ None
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+ """)
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+ s = self.ioclass()
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+ g = self.genclass(s, policy=self.policy.clone(max_line_length=30))
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+ g.flatten(msg)
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+ self.assertEqual(s.getvalue(), self.typ(expected))
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+
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class TestGenerator(TestGeneratorBase, TestEmailBase):
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@@ -224,6 +263,29 @@ class TestGenerator(TestGeneratorBase, TestEmailBase):
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ioclass = io.StringIO
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typ = str
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+ def test_verify_generated_headers(self):
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+ """gh-121650: by default the generator prevents header injection"""
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+ class LiteralHeader(str):
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+ name = 'Header'
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+ def fold(self, **kwargs):
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+ return self
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+
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+ for text in (
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+ 'Value\r\nBad Injection\r\n',
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+ 'NoNewLine'
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+ ):
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+ with self.subTest(text=text):
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+ message = message_from_string(
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+ "Header: Value\r\n\r\nBody",
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+ policy=self.policy,
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+ )
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+
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+ del message['Header']
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+ message['Header'] = LiteralHeader(text)
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+
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+ with self.assertRaises(email.errors.HeaderWriteError):
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+ message.as_string()
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+
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class TestBytesGenerator(TestGeneratorBase, TestEmailBase):
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diff --git a/Lib/test/test_email/test_policy.py b/Lib/test/test_email/test_policy.py
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index e87c275..ff1ddf7 100644
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--- a/Lib/test/test_email/test_policy.py
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+++ b/Lib/test/test_email/test_policy.py
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@@ -26,6 +26,7 @@ class PolicyAPITests(unittest.TestCase):
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'raise_on_defect': False,
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'mangle_from_': True,
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'message_factory': None,
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+ 'verify_generated_headers': True,
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}
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# These default values are the ones set on email.policy.default.
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# If any of these defaults change, the docs must be updated.
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@@ -277,6 +278,31 @@ class PolicyAPITests(unittest.TestCase):
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with self.assertRaises(email.errors.HeaderParseError):
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policy.fold("Subject", subject)
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+ def test_verify_generated_headers(self):
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+ """Turning protection off allows header injection"""
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+ policy = email.policy.default.clone(verify_generated_headers=False)
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+ for text in (
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+ 'Header: Value\r\nBad: Injection\r\n',
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+ 'Header: NoNewLine'
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+ ):
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+ with self.subTest(text=text):
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+ message = email.message_from_string(
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+ "Header: Value\r\n\r\nBody",
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+ policy=policy,
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+ )
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+ class LiteralHeader(str):
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+ name = 'Header'
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+ def fold(self, **kwargs):
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+ return self
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+
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+ del message['Header']
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+ message['Header'] = LiteralHeader(text)
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+
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+ self.assertEqual(
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+ message.as_string(),
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+ f"{text}\nBody",
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+ )
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+
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# XXX: Need subclassing tests.
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# For adding subclassed objects, make sure the usual rules apply (subclass
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# wins), but that the order still works (right overrides left).
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diff --git a/Misc/NEWS.d/next/Library/2024-07-27-16-10-41.gh-issue-121650.nf6oc9.rst b/Misc/NEWS.d/next/Library/2024-07-27-16-10-41.gh-issue-121650.nf6oc9.rst
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new file mode 100644
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index 0000000..83dd28d
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--- /dev/null
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+++ b/Misc/NEWS.d/next/Library/2024-07-27-16-10-41.gh-issue-121650.nf6oc9.rst
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@@ -0,0 +1,5 @@
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+:mod:`email` headers with embedded newlines are now quoted on output. The
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+:mod:`~email.generator` will now refuse to serialize (write) headers that
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+are unsafely folded or delimited; see
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+:attr:`~email.policy.Policy.verify_generated_headers`. (Contributed by Bas
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+Bloemsaat and Petr Viktorin in :gh:`121650`.)
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--
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2.45.2
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@ -0,0 +1,121 @@
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: "Miss Islington (bot)"
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<31488909+miss-islington@users.noreply.github.com>
|
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Date: Mon, 12 Aug 2024 02:35:17 +0200
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Subject: [PATCH] 00436: [CVE-2024-8088] gh-122905: Sanitize names in
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zipfile.Path.
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|
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---
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Lib/test/test_zipfile/_path/test_path.py | 17 +++++
|
||||
Lib/zipfile/_path/__init__.py | 64 ++++++++++++++++++-
|
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...-08-11-14-08-04.gh-issue-122905.7tDsxA.rst | 1 +
|
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3 files changed, 81 insertions(+), 1 deletion(-)
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create mode 100644 Misc/NEWS.d/next/Library/2024-08-11-14-08-04.gh-issue-122905.7tDsxA.rst
|
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|
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diff --git a/Lib/test/test_zipfile/_path/test_path.py b/Lib/test/test_zipfile/_path/test_path.py
|
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index 06d5aab69b..90885dbbe3 100644
|
||||
--- a/Lib/test/test_zipfile/_path/test_path.py
|
||||
+++ b/Lib/test/test_zipfile/_path/test_path.py
|
||||
@@ -577,3 +577,20 @@ def test_getinfo_missing(self, alpharep):
|
||||
zipfile.Path(alpharep)
|
||||
with self.assertRaises(KeyError):
|
||||
alpharep.getinfo('does-not-exist')
|
||||
+
|
||||
+ def test_malformed_paths(self):
|
||||
+ """
|
||||
+ Path should handle malformed paths.
|
||||
+ """
|
||||
+ data = io.BytesIO()
|
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+ zf = zipfile.ZipFile(data, "w")
|
||||
+ zf.writestr("/one-slash.txt", b"content")
|
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+ zf.writestr("//two-slash.txt", b"content")
|
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+ zf.writestr("../parent.txt", b"content")
|
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+ zf.filename = ''
|
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+ root = zipfile.Path(zf)
|
||||
+ assert list(map(str, root.iterdir())) == [
|
||||
+ 'one-slash.txt',
|
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+ 'two-slash.txt',
|
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+ 'parent.txt',
|
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+ ]
|
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diff --git a/Lib/zipfile/_path/__init__.py b/Lib/zipfile/_path/__init__.py
|
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index 78c413563b..42f9fded21 100644
|
||||
--- a/Lib/zipfile/_path/__init__.py
|
||||
+++ b/Lib/zipfile/_path/__init__.py
|
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@@ -83,7 +83,69 @@ def __setstate__(self, state):
|
||||
super().__init__(*args, **kwargs)
|
||||
|
||||
|
||||
-class CompleteDirs(InitializedState, zipfile.ZipFile):
|
||||
+class SanitizedNames:
|
||||
+ """
|
||||
+ ZipFile mix-in to ensure names are sanitized.
|
||||
+ """
|
||||
+
|
||||
+ def namelist(self):
|
||||
+ return list(map(self._sanitize, super().namelist()))
|
||||
+
|
||||
+ @staticmethod
|
||||
+ def _sanitize(name):
|
||||
+ r"""
|
||||
+ Ensure a relative path with posix separators and no dot names.
|
||||
+
|
||||
+ Modeled after
|
||||
+ https://github.com/python/cpython/blob/bcc1be39cb1d04ad9fc0bd1b9193d3972835a57c/Lib/zipfile/__init__.py#L1799-L1813
|
||||
+ but provides consistent cross-platform behavior.
|
||||
+
|
||||
+ >>> san = SanitizedNames._sanitize
|
||||
+ >>> san('/foo/bar')
|
||||
+ 'foo/bar'
|
||||
+ >>> san('//foo.txt')
|
||||
+ 'foo.txt'
|
||||
+ >>> san('foo/.././bar.txt')
|
||||
+ 'foo/bar.txt'
|
||||
+ >>> san('foo../.bar.txt')
|
||||
+ 'foo../.bar.txt'
|
||||
+ >>> san('\\foo\\bar.txt')
|
||||
+ 'foo/bar.txt'
|
||||
+ >>> san('D:\\foo.txt')
|
||||
+ 'D/foo.txt'
|
||||
+ >>> san('\\\\server\\share\\file.txt')
|
||||
+ 'server/share/file.txt'
|
||||
+ >>> san('\\\\?\\GLOBALROOT\\Volume3')
|
||||
+ '?/GLOBALROOT/Volume3'
|
||||
+ >>> san('\\\\.\\PhysicalDrive1\\root')
|
||||
+ 'PhysicalDrive1/root'
|
||||
+
|
||||
+ Retain any trailing slash.
|
||||
+ >>> san('abc/')
|
||||
+ 'abc/'
|
||||
+
|
||||
+ Raises a ValueError if the result is empty.
|
||||
+ >>> san('../..')
|
||||
+ Traceback (most recent call last):
|
||||
+ ...
|
||||
+ ValueError: Empty filename
|
||||
+ """
|
||||
+
|
||||
+ def allowed(part):
|
||||
+ return part and part not in {'..', '.'}
|
||||
+
|
||||
+ # Remove the drive letter.
|
||||
+ # Don't use ntpath.splitdrive, because that also strips UNC paths
|
||||
+ bare = re.sub('^([A-Z]):', r'\1', name, flags=re.IGNORECASE)
|
||||
+ clean = bare.replace('\\', '/')
|
||||
+ parts = clean.split('/')
|
||||
+ joined = '/'.join(filter(allowed, parts))
|
||||
+ if not joined:
|
||||
+ raise ValueError("Empty filename")
|
||||
+ return joined + '/' * name.endswith('/')
|
||||
+
|
||||
+
|
||||
+class CompleteDirs(InitializedState, SanitizedNames, zipfile.ZipFile):
|
||||
"""
|
||||
A ZipFile subclass that ensures that implied directories
|
||||
are always included in the namelist.
|
||||
diff --git a/Misc/NEWS.d/next/Library/2024-08-11-14-08-04.gh-issue-122905.7tDsxA.rst b/Misc/NEWS.d/next/Library/2024-08-11-14-08-04.gh-issue-122905.7tDsxA.rst
|
||||
new file mode 100644
|
||||
index 0000000000..1be44c906c
|
||||
--- /dev/null
|
||||
+++ b/Misc/NEWS.d/next/Library/2024-08-11-14-08-04.gh-issue-122905.7tDsxA.rst
|
||||
@@ -0,0 +1 @@
|
||||
+:class:`zipfile.Path` objects now sanitize names from the zipfile.
|
||||
Loading…
Reference in new issue