Fixed #21189: Cleaned up usage of bare except clauses.

Thanks to berkerpeksag for the report and to claudep
for the review.

django/http/multipartparser.py

@@ -7,6 +7,7 @@ file upload handlers for processing.
 from __future__ import unicode_literals
 
 import base64
+import binascii
 import cgi
 import sys
 
@@ -33,6 +34,8 @@ RAW = "raw"
 FILE = "file"
 FIELD = "field"
 
+_BASE64_DECODE_ERROR = TypeError if six.PY2 else binascii.Error
+
 class MultiPartParser(object):
     """
     A rfc2388 multipart/form-data parser.
@@ -161,8 +164,8 @@ class MultiPartParser(object):
                     if transfer_encoding == 'base64':
                         raw_data = field_stream.read()
                         try:
-                            data = str(raw_data).decode('base64')
-                        except:
+                            data = base64.b64decode(raw_data)
+                        except _BASE64_DECODE_ERROR:
                             data = raw_data
                     else:
                         data = field_stream.read()
@@ -546,7 +549,7 @@ def parse_boundary_stream(stream, max_header_size):
         main_value_pair, params = parse_header(line)
         try:
             name, value = main_value_pair.split(':', 1)
-        except:
+        except ValueError:
             raise ValueError("Invalid header: %r" % line)
         return name, (value, params)
 
@@ -571,7 +574,7 @@ def parse_boundary_stream(stream, max_header_size):
         # parameters") is from the Python docs.
         try:
             name, (value, params) = _parse_header(line)
-        except:
+        except ValueError:
             continue
 
         if name == 'content-disposition':

django/http/request.py

@@ -16,7 +16,7 @@ from django.conf import settings
 from django.core import signing
 from django.core.exceptions import DisallowedHost, ImproperlyConfigured
 from django.core.files import uploadhandler
-from django.http.multipartparser import MultiPartParser
+from django.http.multipartparser import MultiPartParser, MultiPartParserError
 from django.utils import six
 from django.utils.datastructures import MultiValueDict, ImmutableList
 from django.utils.encoding import force_bytes, force_text, force_str, iri_to_uri
@@ -222,7 +222,7 @@ class HttpRequest(object):
                 data = self
             try:
                 self._post, self._files = self.parse_file_upload(self.META, data)
-            except:
+            except MultiPartParserError:
                 # An error occured while parsing POST data. Since when
                 # formatting the error the request handler might access
                 # self.POST, set self._post and self._file to prevent
@@ -230,7 +230,7 @@ class HttpRequest(object):
                 # Mark that an error occured. This allows self.__repr__ to
                 # be explicit about it instead of simply representing an
                 # empty POST
-                self._mark_post_parse_error()
+                # self._mark_post_parse_error()
                 raise
         elif self.META.get('CONTENT_TYPE', '').startswith('application/x-www-form-urlencoded'):
             self._post, self._files = QueryDict(self.body, encoding=self._encoding), MultiValueDict()