Issue #4770: Restrict binascii module to accept only bytes (as specified).

And fix the email package to encode to ASCII instead of ``raw-unicode-escape`` before ASCII-to-binary decoding.

2 files changed, 6 insertions, 4 deletions

diff --git a/Lib/email/base64mime.py b/Lib/email/base64mime.py
index 6cbfdf6ad8..f3bbac1caf 100644
--- a/Lib/email/base64mime.py
+++ b/Lib/email/base64mime.py
@@ -74,12 +74,12 @@ def header_encode(header_bytes, charset='iso-8859-1'):
 
 
 def body_encode(s, maxlinelen=76, eol=NL):
-    """Encode a string with base64.
+    r"""Encode a string with base64.
 
     Each line will be wrapped at, at most, maxlinelen characters (defaults to
     76 characters).
 
-    Each line of encoded text will end with eol, which defaults to "\\n".  Set
+    Each line of encoded text will end with eol, which defaults to "\n".  Set
     this to "\r\n" if you will be using the result of this function directly
     in an email.
     """
diff --git a/Lib/email/message.py b/Lib/email/message.py
index 27a577dac7..520d63d713 100644
--- a/Lib/email/message.py
+++ b/Lib/email/message.py
@@ -198,17 +198,19 @@ class Message:
             return None
         cte = self.get('content-transfer-encoding', '').lower()
         if cte == 'quoted-printable':
+            if isinstance(payload, str):
+                payload = payload.encode('ascii')
             return utils._qdecode(payload)
         elif cte == 'base64':
             try:
                 if isinstance(payload, str):
-                    payload = payload.encode('raw-unicode-escape')
+                    payload = payload.encode('ascii')
                 return base64.b64decode(payload)
             except binascii.Error:
                 # Incorrect padding
                 pass
         elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'):
-            in_file = BytesIO(payload.encode('raw-unicode-escape'))
+            in_file = BytesIO(payload.encode('ascii'))
             out_file = BytesIO()
             try:
                 uu.decode(in_file, out_file, quiet=True)