Hello.
We have currently set dovecot.sieve to insert the text "[SPAM]" at the beginning of an e-mail's subject when it's X-Spam-Score is above 80%. After we set our system as stated the following errors occur:
- When an e-mail's subject contains control characters like [Ctrl+V|^V], dovecot.sieve terminates with an error and an e-mail is not able to be sent. When a MIME encoded Subject like [ＴＥＳＴ^VＭＡＩＬ] is sent we're not able to edit the subject and dovecot ends with an error.
This is a sample of the data that was used in testing. Subject: =?ISO-2022-JP?B?GyRCI1QjRSNTI1QbKEIWGyRCI00jQSNJI0wbKEI=?= X-Spam-Score: 100.00% ↓ Subject: =?ISO-2022-JP?B?GyRCI1QjRSNTI1QbKEIWGyRCI00jQSNJI0wbKEI=?= X-Spam-Score: 100.00%
This is the log generated by the data above.
sieve: info: started log at May 02 10:46:22. main script: line 14: error: addheader action: specified value `[SPAM] ＴＥＳＴ?・・' is invalid.
Aside from [Ctrl + V] the following control charcters also cause errors: backspace Ctrl + A Ctrl + C Ctrl + [ Ctrl + X Ctrl + Y
- When an e-mail's subject line contains a "\0" character, everything following the null character is deleted. When a MIME encoded Subject is sent, for example "ＴＥＳＴ\0ＭＡＩＬ", the subject becomes "[SPAM]ＴＥＳＴ", the characters after the NULL character are deleted and dovecot.sieve ends normally.
This is a sample of the data that we collected. Subject: =?ISO-2022-JP?B?GyRCI1QjRSNTI1QbKEIAGyRCI00jQSNJI0wbKEI=?= X-Spam-Score: 100.00% ↓ Subject: [SPAM] =?utf-8?b?77y077yl77yz77y0?= X-Spam-Score: 100.00%
-Environment ・OS CentOS release 6.5 (Final) x86_64
・Software Version dovecot-2.2.12 dovecot-2.2-pigeonhole-0.4.2
・Results from the "dovecot -n" command.
# 2.2.12: /etc/dovecot/dovecot.conf # OS: Linux 2.6.32-431.5.1.el6.x86_64 x86_64 CentOS release 6.5 (Final) disable_plaintext_auth = no lock_method = dotlock mail_fsync = always mail_gid = vmail mail_location = maildir:~/Maildir mail_nfs_index = yes mail_nfs_storage = yes mail_plugins = quota mail_temp_dir = /var/tmp mail_uid = vmail managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress
comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify
environment mailbox date ihave spamtest spamtestplus editheader mbox_write_locks = dotlock mmap_disable = yes passdb { driver = passwd } plugin { quota = maildir:User quota sieve = ~/Maildir/dovecot.sieve sieve_dir = ~/Maildir/sieve sieve_editheader_max_header_size = 1k sieve_editheader_protected = X-Verified sieve_extensions = +editheader +spamtest +spamtestplus sieve_max_actions = 250 sieve_max_redirects = 100 sieve_spamtest_max_value = 100.00 sieve_spamtest_status_header = X-Spam-Score: ([[:digit:]]+\.[[:digit:]]+)% sieve_spamtest_status_type = score sieve_user_log = /var/log/dovecot.sieve/%d/%u.log } postmaster_address = postmaster@example.jp protocols = pop3 imap service auth { unix_listener auth-userdb { group = vmail mode = 0600 user = vmail } } ssl_ca = </etc/pki/tls/certs/CA.crt ssl_cert = </etc/pki/tls/certs/example.jp.crt ssl_key = </etc/pki/tls/private/example.jp.key submission_host = 127.0.0.1:20025 userdb { args = /etc/dovecot/ldap/userdb.conf.ext driver = ldap } protocol lda { mail_plugins = quota sieve } protocol imap { mail_plugins = quota imap_quota passdb { args = /etc/dovecot/ldap/passdb.conf.ext driver = ldap } } protocol pop3 { passdb { args = /etc/dovecot/ldap/passdb.conf.ext driver = ldap } }
-Contents of the "dovecot.sieve" file user/Maildir/dovecot.sieve
require "fileinto"; require "mailbox"; require "envelope"; require "variables"; require "editheader"; require "spamtestplus"; require "relational"; require "enotify"; require "comparator-i;ascii-numeric";
if spamtest :percent :value "ge" :comparator "i;ascii-numeric" "80" { if exists "subject" { deleteheader :matches "subject" "*"; addheader "Subject" "[SPAM] ${1}"; } else { addheader "Subject" "[SPAM]"; } }
Please reply. Thank you.