From 66c4f3f38b867d8329b28c032bb907fd1a2f22d2 Mon Sep 17 00:00:00 2001 From: Abhilash Raj Date: Wed, 5 Jun 2019 12:56:33 -0400 Subject: bpo-21315: Fix parsing of encoded words with missing leading ws. (#13425) * bpo-21315: Fix parsing of encoded words with missing leading ws. Because of missing leading whitespace, encoded word would get parsed as unstructured token. This patch fixes that by looking for encoded words when splitting tokens with whitespace. Missing trailing whitespace around encoded word now register a defect instead. Original patch suggestion by David R. Murray on bpo-21315. --- Lib/email/_header_value_parser.py | 21 +++++++++++++++++++ Lib/test/test_email/test__header_value_parser.py | 24 ++++++++++++++++++++-- Lib/test/test_email/test_headerregistry.py | 3 ++- .../2019-05-19-10-48-46.bpo-21315.PgXVqF.rst | 4 ++++ 4 files changed, 49 insertions(+), 3 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-05-19-10-48-46.bpo-21315.PgXVqF.rst diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py index 34969ab..35d746a 100644 --- a/Lib/email/_header_value_parser.py +++ b/Lib/email/_header_value_parser.py @@ -96,6 +96,18 @@ EXTENDED_ATTRIBUTE_ENDS = ATTRIBUTE_ENDS - set('%') def quote_string(value): return '"'+str(value).replace('\\', '\\\\').replace('"', r'\"')+'"' +# Match a RFC 2047 word, looks like =?utf-8?q?someword?= +rfc2047_matcher = re.compile(r''' + =\? # literal =? + [^?]* # charset + \? # literal ? + [qQbB] # literal 'q' or 'b', case insensitive + \? # literal ? + .*? # encoded word + \?= # literal ?= +''', re.VERBOSE | re.MULTILINE) + + # # TokenList and its subclasses # @@ -1052,6 +1064,10 @@ def get_encoded_word(value): _validate_xtext(vtext) ew.append(vtext) text = ''.join(remainder) + # Encoded words should be followed by a WS + if value and value[0] not in WSP: + ew.defects.append(errors.InvalidHeaderDefect( + "missing trailing whitespace after encoded-word")) return ew, value def get_unstructured(value): @@ -1104,6 +1120,11 @@ def get_unstructured(value): unstructured.append(token) continue tok, *remainder = _wsp_splitter(value, 1) + # Split in the middle of an atom if there is a rfc2047 encoded word + # which does not have WSP on both sides. The defect will be registered + # the next time through the loop. + if rfc2047_matcher.search(tok): + tok, *remainder = value.partition('=?') vtext = ValueTerminal(tok, 'vtext') _validate_xtext(vtext) unstructured.append(vtext) diff --git a/Lib/test/test_email/test__header_value_parser.py b/Lib/test/test_email/test__header_value_parser.py index 12da3cf..649923f 100644 --- a/Lib/test/test_email/test__header_value_parser.py +++ b/Lib/test/test_email/test__header_value_parser.py @@ -118,7 +118,7 @@ class TestParser(TestParserMixin, TestEmailBase): '=?us-ascii?q?first?==?utf-8?q?second?=', 'first', 'first', - [], + [errors.InvalidHeaderDefect], '=?utf-8?q?second?=') def test_get_encoded_word_sets_extra_attributes(self): @@ -361,6 +361,25 @@ class TestParser(TestParserMixin, TestEmailBase): '=?utf-8?q?foo?==?utf-8?q?bar?=', 'foobar', 'foobar', + [errors.InvalidHeaderDefect, + errors.InvalidHeaderDefect], + '') + + def test_get_unstructured_ew_without_leading_whitespace(self): + self._test_get_x( + self._get_unst, + 'nowhitespace=?utf-8?q?somevalue?=', + 'nowhitespacesomevalue', + 'nowhitespacesomevalue', + [errors.InvalidHeaderDefect], + '') + + def test_get_unstructured_ew_without_trailing_whitespace(self): + self._test_get_x( + self._get_unst, + '=?utf-8?q?somevalue?=nowhitespace', + 'somevaluenowhitespace', + 'somevaluenowhitespace', [errors.InvalidHeaderDefect], '') @@ -546,7 +565,8 @@ class TestParser(TestParserMixin, TestEmailBase): '"=?utf-8?Q?not_really_valid?="', '"not really valid"', 'not really valid', - [errors.InvalidHeaderDefect], + [errors.InvalidHeaderDefect, + errors.InvalidHeaderDefect], '') # get_comment diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py index 7550546..5d9b357 100644 --- a/Lib/test/test_email/test_headerregistry.py +++ b/Lib/test/test_email/test_headerregistry.py @@ -1180,7 +1180,8 @@ class TestAddressHeader(TestHeaderBase): 'rfc2047_atom_in_quoted_string_is_decoded': ('"=?utf-8?q?=C3=89ric?=" ', - [errors.InvalidHeaderDefect], + [errors.InvalidHeaderDefect, + errors.InvalidHeaderDefect], 'Éric ', 'Éric', 'foo@example.com', diff --git a/Misc/NEWS.d/next/Library/2019-05-19-10-48-46.bpo-21315.PgXVqF.rst b/Misc/NEWS.d/next/Library/2019-05-19-10-48-46.bpo-21315.PgXVqF.rst new file mode 100644 index 0000000..dd0dd7f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-05-19-10-48-46.bpo-21315.PgXVqF.rst @@ -0,0 +1,4 @@ +Email headers containing RFC2047 encoded words are parsed despite the missing +whitespace, and a defect registered. Also missing trailing whitespace after +encoded words is now registered as a defect. + -- cgit v0.12