Dovecot Sieve and Postfix header_checks Issue

[Alex Crow]

On 26/09/14 14:10, Klaipedaville on Google wrote:
> Hey! You are right Alex! Many thanks for pointing me to head over to 
> the right direction!
> It was a clash on rules for some reason. Now, I was also right that 
> these two systems could not be used together because the rules 
> declared in different systems to perform the same action (REJECT) 
> cause the error I was having!
> The following rule in default.sieve:
> require ["reject"];
> # rule: Reject on "x-spam-flag" header
> if header :contains "X-Spam-Flag" "YES" {
>       reject "No spamming allowed here.";
>    stop;
> }
> and the following Postfix's regexp header_check rules on the subject 
> field:
> /^Subject:.**{5}SPAM*{5}/                REJECT No spammers allowed here.
> /^Subject:.*\*\*\*\*\*SPAM\*\*\*\*\*/    REJECT No spammers allowed.
> /\s**{5}SPAM*{5}/                        REJECT No spamming 
> hullababballos allowed.

I think it may be this one above. From the postfix manuals:

"By default, matching is case-insensitive, and newlines are not treated 
as special characters. The behavior is controlled by flags, which are 
toggled by appending one or more of the following characters after the 
pattern: *i* (default: on) Toggles the case sensitivity flag. By 
default, matching is case insensitive."

And it looks like * needs escaping there too (if you're trying to match 
exactly 5 asterisks, you should probably do "\*{5}" not just *{5}.

> /^Subject:(.*)SPAM/                      REJECT Spam is not allowed. 
> DISCARD.
> were causing the Dovecot Sieve rejection bounce not to go through. The 
> rules blocked the spam all right but rejection was turned into discard 
> for some reason.
> Now the question is how do I find out which regular expressions will 
> be in conflict with default.sieve scripting rules?

That's just about learning Posix Regex syntax.

> Default.sieve is set to block spam on the X-Spam-Flag header and 
> header_checks is set to block spam on the subject field. I am still 
> clueless why didn't these two "cooperate"? Was it just because they 
> were "told" to perform the same action as per my previous guess?

I'm almost 100% sure that that regex also matched the bounce from your 
sieve rules. There is no mysterious interaction between header_checks 
and sieve rules, it's just your pattern was too liberal in the former.

> But the target to perform this same action on was different... Any 
> more ideas anyone? Alex? Many thanks in advance for any input!

I think if you tune that header_checks file correctly you should have no 
more issues.

Thanks

Alex

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