dovecot - Oct 2008 - antispam plugin claims "antispam signature not found"

Hi,

I am trying to setup the antispam plugin using the direct dspam backend.
I have set

antispam_signature = X-DSPAM-Signature

in dovecot.conf
and in all mails I have signature lines like

X-DSPAM-Signature: 1,49084a24139132188715614

but still, if I try to move a mail into the spam folder, i get the IMAP error
message

"antispam signature not found".

I thought it might have to do with permissions and made sure that the user
running dovecot is able
to execute the dspam binary.
I also tried to enable debug logging to syslog (via the .config file in the make
process) but I do
not see any debug messages showing up; where should these go? to the mail
facility?

Perhaps somebody who has a working setup can shed some light on this?

Yours,
JC

Some weeks ago I asked a question on the antispam plugin; obviously 
nobody could help me. I just worked on it again but made no progress.
Is actually anybody out there running the antispam plugin with dspam?? I 
am willing to write a Wiki page for configuring this as soon as I get it 
to work.

The problem still remains and the outlines are:

- antispam plugin is compiled, configured for dspam and debug is 
switched on.
- plugin starts with dovecot and throws debug info to /var/log/messages 
(debug logging activated via syslog)
- as soon as I move a message into the spam folder it gives an error 
message saying "antispam signature not found"

I checked that the given location for the dspam executable is correct, 
that the user executing it (dovecot?) is actually able to execute dspam 
and that dspam trusts this user. I triple-checked that the signature is 
configured correctly. I have lines like

X-DSPAM-Signature: 1,49084a24139132188715614 

in all mails  and my plugin conf says

    # mail signature (used with any backend requiring a signature)

    antispam_signature = X-DSPAM-Signature

I do not get any error messages in the debug output, only dovecot says:
dovecot: Nov 09 13:19:40 Error: IMAP(****): Next message unexpectedly 
lost from 49

Any ideas? How can I get a more specific debugging for the signature? Or 
might this still be a permission problem?

Here is my plugin config:

# antispam plugin - learn spam from folder
    antispam_signature = X-DSPAM-Signature
    antispam_spam = spam
    antispam_dspam_binary = /usr/local/bin/dspam


Regards, Jakob

Jakob Curdes wrote
> Some weeks ago I asked a question on the antispam plugin; obviously
> nobody could help me. I just worked on it again but made no progress.
> Is actually anybody out there running the antispam plugin with dspam?? I
> am willing to write a Wiki page for configuring this as soon as I get it
> to work.
> .....
> - as soon as I move a message into the spam folder it gives an error
> message saying "antispam signature not found"
Just had this error myself. In my case, the cause was a large spam message 
(above the configured MaxMessageSize parameter for DSPAM) that was skipped 
during tests and thus no signature was added. Might this be true in your 
case?

As a general suggestion for Johannes: maybe it is better to ignore this 
error silently, just move the message and don't call DSPAM?
> I checked that the given location for the dspam executable is correct,
> that the user executing it (dovecot?) is actually able to execute dspam
> and that dspam trusts this user. I triple-checked that the signature is
> configured correctly. I have lines like
> X-DSPAM-Signature: 1,49084a24139132188715614
Another guess: if that comma is not a misprint, something is wrong in your 
setup.

Regards
Eugene

I have the same problem and i'm wondering how should i use this patch ?
I'm not familiar with the patch command.

Thanks.

PS: Sorry for the empty mail

Johannes Berg a ?crit 
> On Tue, 2008-11-11 at 11:42 +0100, Johannes Berg wrote:
>
>   
>> Not sure, I personally think that moving them silently makes errors
>> harder to diagnose. I'll add an option since then you can set this
>> option (antispam_missing_signature = [error|move]) to move after
you've
>> tested and verified that it works just fine.
>>     
>
> Try this patch please, I have only compiled it so far. (there might be
> rejects in the signature-log.c file unless you update to the current git
> tree but you don't care about that)
>
> diff --git a/antispam.7 b/antispam.7
> index d07c1d0..e26db69 100644
> --- a/antispam.7
> +++ b/antispam.7
> @@ -108,6 +108,13 @@ plugin {
>      # mail signature (used with any backend requiring a signature)
>      antispam_signature = X-DSPAM-Signature
>  
> +    # action to take on mails without signature
> +    # (used with any backend requiring a signature)
> +    # (we recommend only setting this to 'move' after verifying
that the
> +    # whole setup is working)
> +    # antispam_signature_missing = move # move silently without training
> +    antispam_signature_missing = error
> +
>      # semicolon-separated list of Trash folders (default unset i.e. none)
>      # antispam_trash >      # antispam_trash = trash;Trash;Deleted
Items
> diff --git a/signature-log.c b/signature-log.c
> index ab8cd6d..5b7b306 100644
> --- a/signature-log.c
> +++ b/signature-log.c
> @@ -99,7 +99,12 @@ int backend_handle_mail(struct
mailbox_transaction_context *t,
>  		return -1;
>  	}
>  
> -	signature = signature_extract(t, mail);
> +	ret = signature_extract(t, mail, &signature);
> +	if (ret)
> +		return ret;
> +
> +	if (!signature)
> +		return 0;
>  
>  	switch (wanted) {
>  	case CLASS_SPAM:
> diff --git a/signature.c b/signature.c
> index 7f9d83b..7ad29d6 100644
> --- a/signature.c
> +++ b/signature.c
> @@ -5,6 +5,7 @@
>  #include "mail-storage-private.h"
>  
>  const char *signature_hdr = "X-DSPAM-Signature";
> +static int signature_nosig_ignore = 0;
>  
>  void signature_init(void)
>  {
> @@ -12,6 +13,16 @@ void signature_init(void)
>  	if (tmp)
>  		signature_hdr = tmp;
>  	debug("signature header line is \"%s\"\n",
signature_hdr);
> +
> +	tmp = get_setting("SIGNATURE_MISSING");
> +	if (!tmp)
> +		tmp = "error";
> +	if (strcmp(tmp, "move") == 0) {
> +		signature_nosig_ignore = 1;
> +		debug("will silently move mails with missing signature\n");
> +	} else if (strcmp(tmp, "error") != 0) {
> +		debug("invalid signature_missing setting '%s',
ignoring\n", tmp);
> +	}
>  }
>  
>  int signature_extract_to_list(struct mailbox_transaction_context *t,
> @@ -23,10 +34,14 @@ int signature_extract_to_list(struct
mailbox_transaction_context *t,
>  
>  	signatures = get_mail_headers(mail, signature_hdr);
>  	if (!signatures || !signatures[0]) {
> -		mail_storage_set_error(t->box->storage,
> -				       ME(NOTPOSSIBLE)
> -				       "antispam signature not found");
> -		return -1;
> +		if (!signature_nosig_ignore) {
> +			mail_storage_set_error(t->box->storage,
> +					       ME(NOTPOSSIBLE)
> +					       "antispam signature not found");
> +			return -1;
> +		} else {
> +			return 0;
> +		}
>  	}
>  
>  	while (signatures[1])
> @@ -42,23 +57,30 @@ int signature_extract_to_list(struct
mailbox_transaction_context *t,
>  	return 0;
>  }
>  
> -const char *signature_extract(struct mailbox_transaction_context *t,
> -			      struct mail *mail)
> +int signature_extract(struct mailbox_transaction_context *t,
> +		      struct mail *mail, const char **signature)
>  {
>  	const char *const *signatures;
>  
>  	signatures = get_mail_headers(mail, signature_hdr);
>  	if (!signatures || !signatures[0]) {
> -		mail_storage_set_error(t->box->storage,
> -				       ME(NOTPOSSIBLE)
> -				       "antispam signature not found");
> -		return NULL;
> +		if (!signature_nosig_ignore) {
> +			mail_storage_set_error(t->box->storage,
> +					       ME(NOTPOSSIBLE)
> +					       "antispam signature not found");
> +			return -1;
> +		} else {
> +			*signature = NULL;
> +			return 0;
> +		}
>  	}
>  
>  	while (signatures[1])
>  		signatures++;
>  
> -	return signatures[0];
> +	*signature = signatures[0];
> +
> +	return 0;
>  }
>  
>  void signature_list_free(struct siglist **list)
> diff --git a/signature.h b/signature.h
> index e25d1b5..1384924 100644
> --- a/signature.h
> +++ b/signature.h
> @@ -16,8 +16,8 @@ void signature_init(void);
>  int signature_extract_to_list(struct mailbox_transaction_context *t,
>  			      struct mail *mail, struct siglist **list,
>  			      enum classification wanted);
> -const char *signature_extract(struct mailbox_transaction_context *t,
> -			      struct mail *mail);
> +int signature_extract(struct mailbox_transaction_context *t,
> +		      struct mail *mail, const char **signature);
>  void signature_list_free(struct siglist **list);
>  
>  extern const char *signature_hdr;
>
>   





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