Hi all,
I'm seeing Dovecot include the string "MISSING_DOMAIN" in fetch
envelope requests when an mailbox's addr-spec part does not have a
domain part.
For example:
C: a022 uid fetch 40 (envelope rfc822.header) S: * 5 FETCH (UID 40 ENVELOPE ("Sat, 15 Aug 2020 12:53:05 +1000" "test {{name}}" (("Michael Gratton" NIL "mike" "vee.net")) (("Michael Gratton" NIL "mike" "vee.net")) (("Michael Gratton" NIL "mike" "vee.net")) (("postgres" NIL "postgres" "MISSING_DOMAIN")) NIL NIL NIL NIL) RFC822.HEADER {literal/244b})
I understand that RFC 5322 require a mailbox to have a domain part, however it is still possible for mail to contain mailboxes that do not. In these cases, Dovecot returning random string such as the above is harmful, since it not possible for IMAP clients to determine whether host name string is actually present or something that the IMAP server has made up.
As a result, an IMAP client has two options: Either display the string as-is, preventing it from providing an appropriately localised explanation or visual indication of the problem in the user interface, or simply avoid ever requesting IMAP envelopes from the server and always download and parse the complete RFC822 headers itself (as I believe Thunderbird does).
The former is untenable since "MISSING_DOMAIN" does not mean anything to non-English speakers, the latter is untenable since it unnecessarily inflates the of volume of data that must be transmitted over the wire to work around a server bug.
In these cases, or when any other part of a required IMAP address structure is missing, Dovecot should return the empty string, e.g. "".
Cheers, //Mike
Dovecot details:
*REDACTED*:~$ sudo dovecot -n # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.19.0-9-amd64 x86_64 Debian 10.4 ext4 # Hostname: *REDACTED* first_valid_uid = *REDACTED* hostname = *REDACTED* last_valid_uid = *REDACTED* lda_original_recipient_header = X-Original-To lmtp_rcpt_check_quota = yes lmtp_save_to_detail_mailbox = yes mail_gid = *REDACTED* mail_home = *REDACTED* mail_location = mdbox:*REDACTED*:UTF-8 mail_privileged_group = mail mail_server_admin = mailto:*REDACTED* mail_temp_dir = *REDACTED* mail_uid = *REDACTED* 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 index ihave duplicate mime foreverypart extracttext imapsieve vnd.dovecot.imapsieve namespace inbox { inbox = yes location = mailbox Drafts { auto = subscribe special_use = \Drafts } mailbox Junk { auto = subscribe autoexpunge = 30 days special_use = \Junk } mailbox Sent { auto = subscribe special_use = \Sent } mailbox Trash { auto = subscribe autoexpunge = 30 days special_use = \Trash } prefix = separator = . type = private } passdb { args = *REDACTED* driver = ldap } plugin { imapsieve_mailbox1_before = file:*REDACTED* imapsieve_mailbox1_causes = COPY imapsieve_mailbox1_name = Junk imapsieve_mailbox2_before = file:*REDACTED* imapsieve_mailbox2_causes = COPY imapsieve_mailbox2_from = Junk imapsieve_mailbox2_name = * recipient_delimiter = + sieve = file://*REDACTED* sieve_before = /etc/dovecot/sieve-before.d sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment +vnd.dovecot.report sieve_pipe_bin_dir = /etc/dovecot/sieve-scripts sieve_plugins = sieve_imapsieve sieve_extprograms sieve_quota_max_storage = 50M } postmaster_address = *REDACTED* protocols = " imap lmtp sieve" service auth-worker { user = mail } service auth { unix_listener *REDACTED* { group = postfix mode = 0666 user = postfix } } service lmtp { process_min_avail = 2 unix_listener *REDACTED* { group = postfix mode = 0600 user = postfix } user = mail } ssl = required ssl_cert = <*REDACTED* ssl_client_ca_dir = *REDACTED* ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it submission_host = *REDACTED*:587 userdb { args = uid=8 driver = static } protocol lmtp { mail_plugins = " sieve" } protocol imap { mail_plugins = " imap_sieve" }
-- Michael Gratton. <https://mjog.vee.net>