From c4e69cc1d84a8e025c6b1894b4749cda8bb1d156 Mon Sep 17 00:00:00 2001 From: "R. David Murray" Date: Tue, 3 Aug 2010 22:14:10 +0000 Subject: #3196: if needed pad a short base64 encoded word before trying to decode. The RFCs encourage following Postel's law: be liberal in what you accept. So if someone forgot to pad the base64 encoded word payload to an even four bytes, we add the padding before handing it to base64mime.decode. Previously, missing padding resulted in a HeaderParseError. Patch by Jason Williams. --- Lib/email/header.py | 3 +++ Lib/email/test/test_email.py | 11 ++++++++++- Misc/ACKS | 1 + Misc/NEWS | 3 +++ 4 files changed, 17 insertions(+), 1 deletion(-) diff --git a/Lib/email/header.py b/Lib/email/header.py index c924d3a..89c1391 100644 --- a/Lib/email/header.py +++ b/Lib/email/header.py @@ -94,6 +94,9 @@ def decode_header(header): word = email.quoprimime.header_decode(encoded_string) decoded_words.append((word, charset)) elif encoding == 'b': + paderr = len(encoded_string) % 4 # Postel's law: add missing padding + if paderr: + encoded_string += '==='[:4 - paderr] try: word = email.base64mime.decode(encoded_string) except binascii.Error: diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py index 09f51df..c311469 100644 --- a/Lib/email/test/test_email.py +++ b/Lib/email/test/test_email.py @@ -1649,6 +1649,15 @@ Re: =?mac-iceland?q?r=8Aksm=9Arg=8Cs?= baz foo bar =?mac-iceland?q?r=8Aksm?= (b'rg', None), (b'\xe5', 'iso-8859-1'), (b'sbord', None)]) + def test_rfc2047_B_bad_padding(self): + s = '=?iso-8859-1?B?%s?=' + data = [ # only test complete bytes + ('dm==', b'v'), ('dm=', b'v'), ('dm', b'v'), + ('dmk=', b'vi'), ('dmk', b'vi') + ] + for q, a in data: + dh = decode_header(s % q) + self.assertEqual(dh, [(a, 'iso-8859-1')]) # Test the MIMEMessage class @@ -3176,7 +3185,7 @@ A very long line that must get split to something other than at the def test_broken_base64_header(self): raises = self.assertRaises - s = 'Subject: =?EUC-KR?B?CSixpLDtKSC/7Liuvsax4iC6uLmwMcijIKHaILzSwd/H0SC8+LCjwLsgv7W/+Mj3IQ?=' + s = 'Subject: =?EUC-KR?B?CSixpLDtKSC/7Liuvsax4iC6uLmwMcijIKHaILzSwd/H0SC8+LCjwLsgv7W/+Mj3I ?=' raises(errors.HeaderParseError, decode_header, s) diff --git a/Misc/ACKS b/Misc/ACKS index 0347f67..75c3ae7 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -854,6 +854,7 @@ Felix Wiemann Gerry Wiener Frank Wierzbicki Bryce "Zooko" Wilcox-O'Hearn +Jason Williams John Williams Sue Williams Gerald S. Williams diff --git a/Misc/NEWS b/Misc/NEWS index a523b8f..dcf2b62 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -37,6 +37,9 @@ Extensions Library ------- +- Issue #3196: email header decoding is now forgiving if an RFC2047 + encoded word encoded in base64 is lacking padding. + - Issue #9444: Argparse now uses the first element of prefix_chars as the option character for the added 'h/help' option if prefix_chars does not contain a '-', instead of raising an error. -- cgit v0.12