commit 75a292e5be429977656acaf846345be9dc0a6b8e
author R. David Murray <rdmurray@bitdance.com> Wed Aug 04 00:05:50 2010 +0000
committer R. David Murray <rdmurray@bitdance.com> Wed Aug 04 00:05:50 2010 +0000
tree 6a78b925d0a0b0a0f7bdd1ad9bf7dfa01ca3163c
parent f38d888f2f9d071191a0defe4f37066c6c8d2233

Merged revisions 83690 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r83690 | r.david.murray | 2010-08-03 18:14:10 -0400 (Tue, 03 Aug 2010) | 10 lines

  #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

diff --git a/Lib/email/header.py b/Lib/email/header.py
index 6e03922..9e91dc2 100644
--- a/Lib/email/header.py
+++ b/Lib/email/header.py
@@ -92,6 +92,9 @@
                 if encoding == 'q':
                     dec = email.quoprimime.header_decode(encoded)
                 elif encoding == 'b':
+                    paderr = len(encoded) % 4   # Postel's law: add missing padding
+                    if paderr:
+                        encoded += '==='[:4 - paderr]
                     try:
                         dec = email.base64mime.decode(encoded)
                     except binascii.Error:

Lib/email/test/test_email.py

diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index 067937a..e1754e9 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -1611,6 +1611,15 @@
                               ('rg', None), ('\xe5', 'iso-8859-1'),
                               ('sbord', None)])
 
+    def test_rfc2047_B_bad_padding(self):
+        s = '=?iso-8859-1?B?%s?='
+        data = [                                # only test complete bytes
+            ('dm==', 'v'), ('dm=', 'v'), ('dm', 'v'),
+            ('dmk=', 'vi'), ('dmk', 'vi')
+          ]
+        for q, a in data:
+            dh = decode_header(s % q)
+            self.assertEqual(dh, [(a, 'iso-8859-1')])
 
 
 # Test the MIMEMessage class
@@ -3064,7 +3073,7 @@
 
     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)
 
 

Lib/email/test/test_email_renamed.py

diff --git a/Lib/email/test/test_email_renamed.py b/Lib/email/test/test_email_renamed.py
index 976d892..481c40f 100644
--- a/Lib/email/test/test_email_renamed.py
+++ b/Lib/email/test/test_email_renamed.py
@@ -2958,7 +2958,7 @@
 
     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)