Re: application/octet-stream sent as 7bit

[Katsumi Yamaoka <yamaoka@jpl.org>]

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>>>>> 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?

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


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--- mm-encode.el~	2009-01-22 08:09:02 +0000
+++ mm-encode.el	2009-09-03 11:24:11 +0000
@@ -148,9 +148,11 @@
 	      (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)))
+    ;; what the preferred encoding is, except that the MIME-type is
+    ;; application/octet-stream or the buffers contain long lines.
+    (when (and (eq bits '7bit)
+	       (not (string-equal mime-type "application/octet-stream"))
+	       (not (mm-long-lines-p 76)))
       (setq encoding bits))
     (mm-encode-content-transfer-encoding encoding mime-type)
     encoding))

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--- mm-encode.el~	2009-01-22 08:09:02 +0000
+++ mm-encode.el	2009-09-03 11:24:11 +0000
@@ -148,9 +148,11 @@
 	      (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)))
+    ;; what the preferred encoding is, except that the MIME-type is
+    ;; any application/* type or the buffers contain long lines.
+    (when (and (eq bits '7bit)
+	       (not (string-match "\\`application/" mime-type))
+	       (not (mm-long-lines-p 76)))
       (setq encoding bits))
     (mm-encode-content-transfer-encoding encoding mime-type)
     encoding))