python · tdwyer · May 31, 2023
@@ -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]



@@ -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(<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org)<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org<<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org><bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org@<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org,<bob@example.com>']),
+           [('', 'alice@example.org'), ('', 'bob@example.com')])
+        eq(utils.getaddresses(['alice@example.org;<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org:<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org.<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org"<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org[<bob@example.com>']),
+           [('', '')])
+        eq(utils.getaddresses(['alice@example.org]<bob@example.com>']),
+           [('', '')])
+
+    def test_parseaddr_parsing_errors(self):
+        """Test for parsing errors from CVE-2023-27043"""
+        eq = self.assertEqual
+        eq(utils.parseaddr(['alice@example.org(<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org)<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org<<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org><bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org@<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org,<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org;<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org:<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org.<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org"<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org[<bob@example.com>']),
+           ('', ''))
+        eq(utils.parseaddr(['alice@example.org]<bob@example.com>']),
+           ('', ''))
+
    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@dom.ain>']),
           [('', ''), ('Jason R. Mastaler', 'jason@dom.ain')])
+        eq(utils.getaddresses(
+           ['Pete(A nice \) chap) <pete(his account)@silly.test(his host)>']),
+           [('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 <jdoe@machine(comment).  example>']),
+           [('John Doe (comment)', 'jdoe@machine.example')])
+        eq(utils.getaddresses(
+           ['"Mary Smith: Personal Account" <smith@home.example>']),
+           [('Mary Smith: Personal Account', 'smith@home.example')])
+        eq(utils.getaddresses(
+           ['Undisclosed recipients:;']),
+           [('', '')])
+        eq(utils.getaddresses(
+           ['<boss@nil.test>, "Giant; \"Big\" Box" <bob@example.net>']),
+           [('', 'boss@nil.test'), ('Giant;  Big  Box', 'bob@example.net')])

    def test_getaddresses_embedded_comment(self):
        """Test proper handling of a nested comment"""