From 7c2284f97d140c4e4a85382bfb3a42440be2464d Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 29 Mar 2021 08:39:05 -0700
Subject: [PATCH] bpo-42988: Remove the pydoc getfile feature (GH-25015)
 (#25066)
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Reference:https://github.com/python/cpython/commit/7c2284f97d140c4e4a85382bfb3a42440be2464d

CVE-2021-3426: Remove the "getfile" feature of the pydoc module which
could be abused to read arbitrary files on the disk (directory
traversal vulnerability). Moreover, even source code of Python
modules can contain sensitive data like passwords. Vulnerability
reported by David Schwörer.
(cherry picked from commit 9b999479c0022edfc9835a8a1f06e046f3881048)

Co-authored-by: Victor Stinner <vstinner@python.org>

Co-authored-by: Victor Stinner <vstinner@python.org>
---
 Lib/pydoc.py                                   | 18 ------------------
 Lib/test/test_pydoc.py                         |  6 ------
 .../2021-03-24-14-16-56.bpo-42988.P2aNco.rst   |  4 ++++
 3 files changed, 4 insertions(+), 24 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Security/2021-03-24-14-16-56.bpo-42988.P2aNco.rst

diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 978e4cd0baa5ba..9677c0d0468db0 100644
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -2348,9 +2348,6 @@ def page(self, title, contents):
 %s</head><body bgcolor="#f0f0f8">%s<div style="clear:both;padding-top:.5em;">%s</div>
 </body></html>''' % (title, css_link, html_navbar(), contents)
 
-        def filelink(self, url, path):
-            return '<a href="getfile?key=%s">%s</a>' % (url, path)
-
 
     html = _HTMLDoc()
 
@@ -2436,19 +2433,6 @@ def bltinlink(name):
             'key = %s' % key, '#ffffff', '#ee77aa', '<br>'.join(results))
         return 'Search Results', contents
 
-    def html_getfile(path):
-        """Get and display a source file listing safely."""
-        path = urllib.parse.unquote(path)
-        with tokenize.open(path) as fp:
-            lines = html.escape(fp.read())
-        body = '<pre>%s</pre>' % lines
-        heading = html.heading(
-            '<big><big><strong>File Listing</strong></big></big>',
-            '#ffffff', '#7799ee')
-        contents = heading + html.bigsection(
-            'File: %s' % path, '#ffffff', '#ee77aa', body)
-        return 'getfile %s' % path, contents
-
     def html_topics():
         """Index of topic texts available."""
 
@@ -2540,8 +2524,6 @@ def get_html_page(url):
                 op, _, url = url.partition('=')
                 if op == "search?key":
                     title, content = html_search(url)
-                elif op == "getfile?key":
-                    title, content = html_getfile(url)
                 elif op == "topic?key":
                     # try topics first, then objects.
                     try:
diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 198cea93eb52d7..baad8212c573dc 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -1049,18 +1049,12 @@ def test_url_requests(self):
             ("topic?key=def", "Pydoc: KEYWORD def"),
             ("topic?key=STRINGS", "Pydoc: TOPIC STRINGS"),
             ("foobar", "Pydoc: Error - foobar"),
-            ("getfile?key=foobar", "Pydoc: Error - getfile?key=foobar"),
             ]
 
         with self.restrict_walk_packages():
             for url, title in requests:
                 self.call_url_handler(url, title)
 
-            path = string.__file__
-            title = "Pydoc: getfile " + path
-            url = "getfile?key=" + path
-            self.call_url_handler(url, title)
-
 
 class TestHelper(unittest.TestCase):
     def test_keywords(self):
diff --git a/Misc/NEWS.d/next/Security/2021-03-24-14-16-56.bpo-42988.P2aNco.rst b/Misc/NEWS.d/next/Security/2021-03-24-14-16-56.bpo-42988.P2aNco.rst
new file mode 100644
index 00000000000000..4b42dd05305a83
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2021-03-24-14-16-56.bpo-42988.P2aNco.rst
@@ -0,0 +1,4 @@
+CVE-2021-3426: Remove the ``getfile`` feature of the :mod:`pydoc` module which
+could be abused to read arbitrary files on the disk (directory traversal
+vulnerability). Moreover, even source code of Python modules can contain
+sensitive data like passwords. Vulnerability reported by David Schwörer.
