On 11/28/2016 3:28 PM, Volker Wysk wrote:
> Hi!
>
> "Dovecot always logs a detailed error message if something goes wrong.
> If it doesn't, it's considered a bug and will be fixed." (http://
> wiki2.dovecot.org/Logging)
>
> I'm trying to set up a spam filter with dovecot-antispam and dspam as backend.
>
> When I move a spam message from INBOX to Spam, I get this in syslog:
>
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_unsure(Spam): 0
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_trash(INBOX): 0
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_trash(Spam): 0
> Nov 28 21:15:58 desktop imap: antispam: mail copy: from trash: 0, to trash: 0
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_spam(INBOX): 0
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_spam(Spam): 1
> Nov 28 21:15:58 desktop imap: antispam: mailbox_is_unsure(INBOX): 0
> Nov 28 21:15:58 desktop imap: antispam: mail copy: src spam: 0, dst spam: 1,
> src unsure: 0
>
> There are no log entries about how dspam is called, or what goes on. Indeed,
> dspam doesn't get called at all. I know, because I've examined the antispam-
> plugin source code. There would be a log message if dspam was called.
>
> It's hard to study the source code, because there are hardly any comments.
>
> I have been able to trace the problem to function signature_extract_to_list()
> in signature.c. There, -1 is returned:
>
> int signature_extract_to_list(const struct signature_config *cfg,
> struct mailbox_transaction_context *t,
> struct mail *mail, struct siglist **list,
> enum classification wanted)
> {
> const char *const *signatures;
> struct siglist *item;
>
> signatures = get_mail_headers(mail, cfg->signature_hdr);
> if (!signatures || !signatures[0]) {
> if (!cfg->signature_nosig_ignore) {
>
> mail_storage_set_error(t->box->storage,
> ME(NOTPOSSIBLE)
> "antispam signature not found");
> return -1; /* <-- HERE */
> } else {
> return 0;
> }
> }
>
> while (signatures[1])
> signatures++;
>
> item = i_new(struct siglist, 1);
> item->next = *list;
> item->wanted = wanted;
> item->sig = i_strdup(signatures[0]);
>
> *list = item;
>
> return 0;
> }
>
> So, what's happening is "antispam signature not found". My question: What
> does this mean? What's going on?
>
I too encountered this same issue after upgrading to 2.2.27. I traced it
to an apparent change in Dovecot's mail_get_headers() function, which
now returns a non-zero value even when the header is found. This wasn't
the behavior in 2.2.24, though I'm not sure if it was in .25 or .26.
I haven't tracked down the details further.
Anyway, the antispam plugin uses this API to find the X-DSPAM-Signature
header, and the change causes the plugin to abort. This happens in the
plugin's antispam-plugin.h wrapper, which I modified as follows.
I'm confused why the dovecot API behavior changed, but I hope this
helps!
Tom.
*** antispam-plugin.h 2016-12-17 17:25:48.571704442 -0500
--- antispam-plugin.h.orig 2016-12-17 17:24:55.010093416 -0500
***************
*** 268,275 ****
static inline const char *const *
get_mail_headers(struct mail *mail, const char *hdr)
{
! const char *const *ret = NULL;
! mail_get_headers(mail, hdr, &ret);
return ret;
}
--- 268,276 ----
static inline const char *const *
get_mail_headers(struct mail *mail, const char *hdr)
{
! const char *const *ret;
! if (mail_get_headers(mail, hdr, &ret))
! return NULL;
return ret;
}