Fixed #19036 -- Fixed base64 uploads decoding

Thanks anthony at adsorbtion.org for the report, and johannesl for
bringing the patch up-to-date.

1 files changed, 6 insertions, 0 deletions

diff --git a/django/http/multipartparser.py b/django/http/multipartparser.py
index 9413a1eabb..edf98f6e49 100644
--- a/django/http/multipartparser.py
+++ b/django/http/multipartparser.py
@@ -199,6 +199,12 @@ class MultiPartParser(object):
                         for chunk in field_stream:
                             if transfer_encoding == 'base64':
                                 # We only special-case base64 transfer encoding
+                                # We should always read base64 streams by multiple of 4
+                                over_bytes = len(chunk) % 4
+                                if over_bytes:
+                                    over_chunk = field_stream.read(4 - over_bytes)
+                                    chunk += over_chunk
+
                                 try:
                                     chunk = base64.b64decode(chunk)
                                 except Exception as e: