Re: application/octet-stream sent as 7bit

[Dmitri Paduchikh <dpaduch@k66.ru>]

[-- Attachment #1: Type: text/plain, Size: 1606 bytes --]

Katsumi Yamaoka:

>>>>>> Dmitri Paduchikh wrote:
>> In some cases Gnus sends application/octet-stream attachments in
>> unencoded form:

>> ,----
>>| --=-=-=
>>| Content-Type: application/octet-stream
>>| Content-Disposition: attachment; filename=test.sh
>>|
>>| #!/bin/sh
>>| echo test
>> `----

>> I am concerned that contents can change when transferring a message.
>> Think of EOL conversions, ">From " stuff, etc. Such changes can corrupt
>> shell script, for example.

>> In general, RFC 2046 says that application/octet-stream denotes
>> arbitrary binary data. For arbitrary binary data I would expect that it
>> is transferred exactly as is, even if it looks like a 7-bit text.

> Agreed.  Aren't there any other application/* types that should
> not be forced to be encoded by 7bit?  Otherwise, is it better not
> to force the 7bit encoding to all application/* types?

Hmm... It is unclear to me whether other application/* (or audio/*,
image/*, video/*) require protection from this behavior. Although binary
data most likely isn't 7-bit, it may be 7-bit in principle. IMO, in such
case it would be preferable to provide safe default behavior and means
to change it if user wants to. 7bit enforcement breaks both of these
principles (safe default and user control) thus I would rather remove it
completely as in the patch below. Are there any situations when it is
desirable to enforce 7bit?

> Here are two patches; one is for excluding application/octet-stream,
> the other is for excluding application/*.

Thank you. The following patch is a variation of your patches.

-- 
Dmitri Paduchikh


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: Type: text/x-patch, Size: 717 bytes --]

diff --git a/lisp/mm-encode.el b/lisp/mm-encode.el
index 39b83ff..963936d 100644
--- a/lisp/mm-encode.el
+++ b/lisp/mm-encode.el
@@ -145,13 +145,7 @@ The encoding used is returned."
 	 (encoding
 	  (or (and (listp type)
 		   (cadr (assq 'encoding type)))
-	      (mm-content-transfer-encoding mime-type)))
-	 (bits (mm-body-7-or-8)))
-    ;; We force buffers that are 7bit to be unencoded, no matter
-    ;; what the preferred encoding is.
-    ;; Only if the buffers don't contain lone lines.
-    (when (and (eq bits '7bit) (not (mm-long-lines-p 76)))
-      (setq encoding bits))
+	      (mm-content-transfer-encoding mime-type))))
     (mm-encode-content-transfer-encoding encoding mime-type)
     encoding))