bpo-27397: Make email module properly handle invalid-length base64 strings (GH-7583) (GH-7664)
When attempting to base64-decode a payload of invalid length (1 mod 4),
properly recognize and handle it. The given data will be returned as-is,
i.e. not decoded, along with a new defect, InvalidBase64LengthDefect.
(cherry picked from commit c3f55be7dd012b7e92901627d0b31c21e983ccb4)
Co-authored-by: Tal Einat <taleinat+github@gmail.com>
diff --git a/Doc/library/email.errors.rst b/Doc/library/email.errors.rst
index 5838767..511ad16 100644
--- a/Doc/library/email.errors.rst
+++ b/Doc/library/email.errors.rst
@@ -108,3 +108,7 @@
* :class:`InvalidBase64CharactersDefect` -- When decoding a block of base64
encoded bytes, characters outside the base64 alphabet were encountered.
The characters are ignored, but the resulting decoded bytes may be invalid.
+
+* :class:`InvalidBase64LengthDefect` -- When decoding a block of base64 encoded
+ bytes, the number of non-padding base64 characters was invalid (1 more than
+ a multiple of 4). The encoded block was kept as-is.