Re: Possible problem with Gnus

[Reiner Steib]

On Tue, May 11 2004, Paul Jarc wrote:

> Reiner Steib <address@hidden> wrote:
>> E.g. xdvi is launched as "xdvi -safer %s".
>
> What if the attachment's filename contains characters that would be
> dangerous for the shell?  Does Gnus use the filename in the message,
> or generate its own?

Gnus creates a new temporary directory[1].  The filename is rewritten
using `mm-file-name-rewrite-functions'[1,2] in order to avoid
dangerous characters.

(Cc-ing Jesper Harder, who improved `mm-file-name-rewrite-functions'
recently.)  I wonder if e.g. »`« and »&« should be removed too.
Jesper, could you explain why those are not deleted in
`mm-file-name-delete-gotchas'?  Testing...  Okay, Gnus already seems
to do proper quoting:

  [2. application/postscript; dan`ls`erous.ps]
  -> »Displaying gv -safer /tmp/ste/emm.11740F6T/dan\`ls\`erous.ps...«.

Bye, Reiner.

[1] See the function `mm-display-external' in `mm-decode.el':

--8<---------------cut here---------------start------------->8---
        (let* ((dir (mm-make-temp-file
                     (expand-file-name "emm." mm-tmp-directory) 'dir))
               (filename (or
                          (mail-content-type-get
                           (mm-handle-disposition handle) 'filename)
                          (mail-content-type-get
                           (mm-handle-type handle) 'name)))
[...]
               file buffer)
          ;; We create a private sub-directory where we store our files.
          (set-file-modes dir 448)
          (if filename
              (setq file (expand-file-name
                          (gnus-map-function mm-file-name-rewrite-functions
                                             (file-name-nondirectory filename))
                          dir))
            (setq file (mm-make-temp-file (expand-file-name "mm." dir))))
--8<---------------cut here---------------end--------------->8---

[2]
,----[ (info "(emacs-mime)Files and Directories") ]
| `mm-file-name-rewrite-functions'
|      A list of functions used for rewriting file names of MIME parts.
|      Each function is applied successively to the file name.
|      Ready-made functions include
| 
|     `mm-file-name-delete-control'
|           Delete all control characters.
| 
|     `mm-file-name-delete-gotchas'
|           Delete characters that could have unintended consequences
|           when used with flawed shell scripts, i.e. `|', `>' and `<';
|           and `-', `.' as the first character.
`----
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo--- PGP key available via WWW   http://rsteib.home.pages.de/