From 887b8caef1f64e5e7aa303d09f38c19f4281ecbb Mon Sep 17 00:00:00 2001 From: Thomas Dwyer Date: Tue, 30 May 2023 21:28:39 -0500 Subject: [PATCH] gh-102988: Detect email address parsing errors and return empty tupleto indicate the parsing error (old API) --- Lib/email/utils.py | 60 ++++++++++++++++++++--- Lib/test/test_email/test_email.py | 81 +++++++++++++++++++++++++++++-- 2 files changed, 132 insertions(+), 9 deletions(-) diff --git a/Lib/email/utils.py b/Lib/email/utils.py index 81da5394ea1695..5bcbb1da0c18a8 100644 --- a/Lib/email/utils.py +++ b/Lib/email/utils.py @@ -106,12 +106,51 @@ def formataddr(pair, charset='utf-8'): return address +def _pre_parse_validation(email_header_fields): + accepted_values = [] + for v in email_header_fields: + s = v.replace('\\(', '').replace('\\)', '') + if s.count('(') != s.count(')'): + v = "('', '')" + accepted_values.append(v) + + return accepted_values + + +def _post_parse_validation(parsed_email_header_tuples): + accepted_values = [] + # The parser would have parsed a correctly formatted domain-literal + # The existence of an [ after parsing indicates a parsing failure + for v in parsed_email_header_tuples: + if '[' in v[1]: + v = ('', '') + accepted_values.append(v) + + return accepted_values + def getaddresses(fieldvalues): - """Return a list of (REALNAME, EMAIL) for each fieldvalue.""" - all = COMMASPACE.join(str(v) for v in fieldvalues) + """Return a list of (REALNAME, EMAIL) for each fieldvalue, + unless the parse fails, in which case return a 2-tuple of ('', '') + will be returned in it's place. + + If the resulting list is greater than number of items in the fieldvalues + list, a list containing a single empty 2-tuple [('', '')] will be returned. + """ + fieldvalues = [str(v) for v in fieldvalues] + fieldvalues = _pre_parse_validation(fieldvalues) + all = COMMASPACE.join(v for v in fieldvalues) a = _AddressList(all) - return a.addresslist + result = _post_parse_validation(a.addresslist) + + n = 0 + for v in fieldvalues: + n += v.count(',') + 1 + + if len(result) != n: + return [('', '')] + + return result def _format_timetuple_and_zone(timetuple, zone): @@ -212,9 +251,18 @@ def parseaddr(addr): Return a tuple of realname and email address, unless the parse fails, in which case return a 2-tuple of ('', ''). """ - addrs = _AddressList(addr).addresslist - if not addrs: - return '', '' + if isinstance(addr, list): + addr = addr[0] + + if not isinstance(addr, str): + return ('', '') + + addr = _pre_parse_validation([addr])[0] + addrs = _post_parse_validation(_AddressList(addr).addresslist) + + if not addrs or len(addrs) > 1: + return ('', '') + return addrs[0] diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py index 44b405740c4403..f7f5a55e138750 100644 --- a/Lib/test/test_email/test_email.py +++ b/Lib/test/test_email/test_email.py @@ -3319,15 +3319,90 @@ def test_getaddresses(self): [('Al Person', 'aperson@dom.ain'), ('Bud Person', 'bperson@dom.ain')]) + def test_getaddresses_parsing_errors(self): + """Test for parsing errors from CVE-2023-27043""" + eq = self.assertEqual + eq(utils.getaddresses(['alice@example.org(']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org)']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org<']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org>']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org@']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org,']), + [('', 'alice@example.org'), ('', 'bob@example.com')]) + eq(utils.getaddresses(['alice@example.org;']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org:']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org.']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org"']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org[']), + [('', '')]) + eq(utils.getaddresses(['alice@example.org]']), + [('', '')]) + + def test_parseaddr_parsing_errors(self): + """Test for parsing errors from CVE-2023-27043""" + eq = self.assertEqual + eq(utils.parseaddr(['alice@example.org(']), + ('', '')) + eq(utils.parseaddr(['alice@example.org)']), + ('', '')) + eq(utils.parseaddr(['alice@example.org<']), + ('', '')) + eq(utils.parseaddr(['alice@example.org>']), + ('', '')) + eq(utils.parseaddr(['alice@example.org@']), + ('', '')) + eq(utils.parseaddr(['alice@example.org,']), + ('', '')) + eq(utils.parseaddr(['alice@example.org;']), + ('', '')) + eq(utils.parseaddr(['alice@example.org:']), + ('', '')) + eq(utils.parseaddr(['alice@example.org.']), + ('', '')) + eq(utils.parseaddr(['alice@example.org"']), + ('', '')) + eq(utils.parseaddr(['alice@example.org[']), + ('', '')) + eq(utils.parseaddr(['alice@example.org]']), + ('', '')) + def test_getaddresses_nasty(self): eq = self.assertEqual eq(utils.getaddresses(['foo: ;']), [('', '')]) - eq(utils.getaddresses( - ['[]*-- =~$']), - [('', ''), ('', ''), ('', '*--')]) + eq(utils.getaddresses(['[]*-- =~$']), [('', '')]) eq(utils.getaddresses( ['foo: ;', '"Jason R. Mastaler" ']), [('', ''), ('Jason R. Mastaler', 'jason@dom.ain')]) + eq(utils.getaddresses( + ['Pete(A nice \) chap) ']), + [('Pete (A nice ) chap his account his host)', 'pete@silly.test')]) + eq(utils.getaddresses( + ['(Empty list)(start)Undisclosed recipients :(nobody(I know))']), + [('', '')]) + eq(utils.getaddresses( + ['Mary <@machine.tld:mary@example.net>, , jdoe@test . example']), + [('Mary', 'mary@example.net'), ('', ''), ('', 'jdoe@test.example')]) + eq(utils.getaddresses( + ['John Doe ']), + [('John Doe (comment)', 'jdoe@machine.example')]) + eq(utils.getaddresses( + ['"Mary Smith: Personal Account" ']), + [('Mary Smith: Personal Account', 'smith@home.example')]) + eq(utils.getaddresses( + ['Undisclosed recipients:;']), + [('', '')]) + eq(utils.getaddresses( + [', "Giant; \"Big\" Box" ']), + [('', 'boss@nil.test'), ('Giant; Big Box', 'bob@example.net')]) def test_getaddresses_embedded_comment(self): """Test proper handling of a nested comment"""