Gnus mishandled PGP clearsigned files in attachments

Gnus mishandled PGP clearsigned files in attachments

[Juliusz Chroboczek]

Hi,

(I've also reported this as Debian bug 348383 -- sorry for the spamming.)

Gnus mishandles ASCII-armored GPG signed files sent as attachments.
An example of such a file is available on gmane in group
gmane.comp.version-control.darcs.devel under

  Message-ID: <200601142043.k0EKhTvU018182@ms-smtp-02.nyroc.rr.com>

There are two mis-behaviours:

  - when displaying such a message, Gnus will attempt to verify the
    signature before de-QP-ing.  Obviously, this fails;
  - when saving such an attachment, Gnus discards the PGP armour (and
    therefore the signature).  This makes it impossible to check the
    signature.

Mutt simply treats the attachment as plain text:

  - when displaying such a message, Mutt doesn't attempt to do any
    processing.
  - when saving such an attachment, Mutt saves the pristine, de-QP-ed
    attachment, which it is then possible to verify.

Ideally, Gnus would behave like Mutt when saving the attachment, but
verify the signature after de-QP-ing when displaying the message.

(In case you're interested: there are very good reasons for using this
sort of attachments -- the attachment can be verified after being
saved without using a mailer, which is not the case with PGP/MIME.
This is a needed feature in Darcs.)

Thanks for your help,

                                        Juliusz Chroboczek

Re: Gnus mishandled PGP clearsigned files in attachments

[Katsumi Yamaoka]

>>>>> In <7ifynf984w.fsf@lanthane.pps.jussieu.fr> Juliusz Chroboczek wrote:

> Gnus mishandles ASCII-armored GPG signed files sent as attachments.
> An example of such a file is available on gmane in group
> gmane.comp.version-control.darcs.devel under

>   Message-ID: <200601142043.k0EKhTvU018182@ms-smtp-02.nyroc.rr.com>

> There are two mis-behaviours:

>   - when displaying such a message, Gnus will attempt to verify the
>     signature before de-QP-ing.  Obviously, this fails;

Fixed in CVS.  Thanks for the good example.

>   - when saving such an attachment, Gnus discards the PGP armour (and
>     therefore the signature).  This makes it impossible to check the
>     signature.

We don't have a means to do it up to now, but I'll grope the way
to achieve it...

Re: Gnus mishandled PGP clearsigned files in attachments

[Katsumi Yamaoka]

>>>>> In <b4m1wyzwo5v.fsf@jpl.org> Katsumi Yamaoka wrote:

>>   - when saving such an attachment, Gnus discards the PGP armour (and
>>     therefore the signature).  This makes it impossible to check the
>>     signature.

> We don't have a means to do it up to now, but I'll grope the way
> to achieve it...

I've modified the Gnus trunk (i.e., No Gnus) so as to display
extra buttons that point parts containing PGP signatures.  You
can enable it by typing the M-t key in the summary buffer, or
always display those buttons by setting the
`mm-uu-buttonize-original-text-parts' variable to non-nil.

>> gmane.comp.version-control.darcs.devel under

>>   Message-ID: <200601142043.k0EKhTvU018182@ms-smtp-02.nyroc.rr.com>

And this article will be displayed as follows:

[2. The original part of --- text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]...

[[PGP Signed Part:Undecided]]
[3. text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]

The part 2 contains a PGP signature, but the part 3 doesn't.  Is
this behavior ok?

P.S. I made a mistake in writing cvs log, sorry.

Re: Gnus mishandled PGP clearsigned files in attachments

[Katsumi Yamaoka]

>>>>> In <b4mvewbqnh5.fsf@jpl.org> Katsumi Yamaoka wrote:

>>> gmane.comp.version-control.darcs.devel under

>>>   Message-ID: <200601142043.k0EKhTvU018182@ms-smtp-02.nyroc.rr.com>

> And this article will be displayed as follows:

> [2. The original part of --- text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]...

> [[PGP Signed Part:Undecided]]
> [3. text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]

> The part 2 contains a PGP signature, but the part 3 doesn't.  Is
> this behavior ok?

Well, I don't like this interface very much.  In that case, most
users seem to be confused by the part 2 and the part 3 that are
very much alike.  So, I want to disable it by default, or
withdraw it.  WDYT?

BTW, you can set the `gnus-article-emulate-mime' variable to nil
so that Gnus might display signed parts which aren't MIME as is.

Re: Gnus mishandled PGP clearsigned files in attachments

[Katsumi Yamaoka]

>>>>> In <b4mslrfnooo.fsf@jpl.org> Katsumi Yamaoka wrote:

>>>> gmane.comp.version-control.darcs.devel under

>>>>   Message-ID: <200601142043.k0EKhTvU018182@ms-smtp-02.nyroc.rr.com>

>> And this article will be displayed as follows:

>> [2. The original part of --- text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]...

>> [[PGP Signed Part:Undecided]]
>> [3. text/x-darcs-patch; save-email-description-file-if-a-send-fails.dpatch]

> Well, I don't like this interface very much.  In that case, most
> users seem to be confused by the part 2 and the part 3 that are
> very much alike.  So, I want to disable it by default, or
> withdraw it.  WDYT?

I've withdrawn it.  Instead, I've implemented the new features
in No Gnus.  You can now use the following commands at security
buttons in addition to RET and mouse-2:

`o'	gnus-mime-security-save-part
`|'	gnus-mime-security-pipe-part
`mouse-3' gnus-mime-security-button-menu

`o' saves a part containing a PGP signature to a file, `|' sends
a part to a process, and `mouse-3' pops up a menu.  For instance,
typing `| gpg --verify' will verify a signature.  Note that you
have to make Gnus show security buttons in the article buffer.
To do that, type `M-t' in the summary buffer or customize the
`gnus-buttonized-mime-types' variable as follows:

(add-to-list 'gnus-buttonized-mime-types "multipart/signed")

Could you try the CVS trunk?

Re: Gnus mishandled PGP clearsigned files in attachments

[Juliusz Chroboczek]

Katsumi Yamaoka <yamaoka@jpl.org>:

> I've withdrawn it.  Instead, I've implemented the new features
> in No Gnus.  You can now use the following commands at security
> buttons in addition to RET and mouse-2:
>
> `o'	gnus-mime-security-save-part
> `|'	gnus-mime-security-pipe-part
> `mouse-3' gnus-mime-security-button-menu
>
> `o' saves a part containing a PGP signature to a file, `|' sends
> a part to a process,

That's exactly the functionality I need -- thanks a lot.

> Could you try the CVS trunk?

Will do, but unfortunately not before Friday.

Thanks again,

                                        Juliusz