February 2020 - dovecot

auth-client via SSL?
by Heiko Schlittermann 05 Feb '20

05 Feb '20

Hello, does dovecot support tls-on-connect for AF INET based auth-client sockets? Rationale behind my question: Exim can use the Dovecot auth-client socket to delegate the SMTP-AUTH authentication to Dovecot. Currently Exim supports the AF UNIX only for this socket. Jeremy makes progress in extending this to use AF INET sockets too. While it works with clear text communication already, during testing I was to setup the auch-client socket as an TLS server (tls-on-connect). It doesn't seem to work as I'd expect. The socket still offers clear-text only. Here my configuration snippets regarding this socket ssl = yes ssl_cert = </etc/dovecot/private/server.pem ssl_key = </etc/dovecot/private/server.pem service auth { … unix_listener auth-client { group = _exim mode = 0660 } inet_listener auth-client { name = exim port = 4711 ssl = yes } } SSL connections to :993 work as expected. Best regards from Dresden/Germany Viele Grüße aus Dresden Heiko Schlittermann -- SCHLITTERMANN.de ---------------------------- internet & unix support - Heiko Schlittermann, Dipl.-Ing. (TU) - {fon,fax}: +49.351.802998{1,3} - gnupg encrypted messages are welcome --------------- key ID: F69376CE - ! key id 7CBF764A and 972EAC9F are revoked since 2015-01 ------------ -

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Submission service, XCLIENT and HELO
by Riccardo Alfieri 04 Feb '20

04 Feb '20

Hello, I'm using version 2.3.4.1 and I have a fairly simple setup based on a submission server where I run dovecot and a relay server with postfix. The relevant part of dovecot's config is as follows (sanitized): hostname = submission.domain.local submission_client_workarounds = whitespace-before-path submission_relay_host = 192.168.1.1 <- postfix submission_relay_port = 25 submission_relay_trusted = yes Postfix is configured as follows: smtpd_authorized_xclient_hosts = 192.168.1.2 <- submission server Everything apparently works as expected, meaning that I can correctly authenticate on the submission server and the email is relayed to postfix, where I can see the original MUA's IP correctly logged. There is, however, a little problem with the client HELO string that is not being forwarded to postfix. Instead of having the MUA HELO, I see the submission server HELO, as shown in the following tcpdump taken on the postfix server: 220 postfix.domain.local ESMTP Postfix (Ubuntu) EHLO submission.domain.local 250-postfix.domain.local 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-STARTTLS 250-AUTH DIGEST-MD5 CRAM-MD5 NTLM PLAIN LOGIN 250-AUTH=DIGEST-MD5 CRAM-MD5 NTLM PLAIN LOGIN 250-XCLIENT NAME ADDR PROTO HELO REVERSE_NAME PORT LOGIN DESTADDR DESTPORT 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 SMTPUTF8 XCLIENT ADDR=192.168.1.3 PORT=57116 LOGIN=riccardo-at-domain.local 220 postfix.domain.local ESMTP Postfix (Ubuntu) EHLO submission.domain.local 250-postfix.domain.local 250-PIPELINING ... As you can see the first EHLO is correctly done with the submission server's hostname, but the subsequent one after XCLIENT is -still- the same hostname, while I was expecting that to be the one forwarded from the MUA, or possibly a "HELO=somethingelse" in the XCLIENT line. I've looked almost everywhere and I couldn't find a way to make dovecot use the MUA's HELO string. The question I'm asking is if there is a way to have the MUA's HELO forwarded to the relay server in some way, or if this is a bug or an expected behaviour. Thanks for any help you could give -- Best regards, Riccardo Alfieri Spamhaus Technology https://www.spamhaustech.com/

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Vacation use different SMTP server
by azurit＠pobox.sk 03 Feb '20

03 Feb '20

Hi, in our setup, we have two SMTP servers: - one for receiving messages (this one is using Dovecot's LMTP for delivery) - one for sending messages (this one is used by our users as outgoing SMTP server) Only the first one has list of local domains, local e-mail accoutns etc. so the second one will ALWAYS use MX records for delivery - with this setup, we can allow to our users to add any domain to their accounts (for example, if someone will add gmail.com and create e-mail accounts on it, it's complete safe because we will never deliver mail for gmail.com locally). The only problem seems to be vacation messages (maybe other messages send by sieve), as Dovecot is using the first SMTP server for sending. My questions: Can i set different SMTP server for sieve messages? How exactly is Dovecot/Sieve choosing which SMTP server will be used? Thanks. azur

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mail_filter and mail_filter_out broken somewhere between 2.2.27 and 2.3.4, problem still exists in git
by Michael Fincham 03 Feb '20

03 Feb '20

Hi Dovecot folks, I recently reported this bug in Debian (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=939442) after a stretch -> buster upgrade, however since I can reproduce it using the latest 2.4 from git I thought perhaps I ought to take it straight upstream. Here's the text I provided Debian about the issue, and below that I've included a syslog snip showing the same issue in a fresh build of git master as well. mail_filter_out seems to fully panic (backtrace below), whereas mail_filter is just behaving oddly. Thanks :) ***************************** Package: dovecot-core Version: 2.3.4.1-5+deb10u1 Severity: important Hi Dovecot maintainers, After upgrading from the latest stretch version of dovecot-core (2.2.27-3+deb9u5) to buster (2.3.4.1-5+deb10u1) the "mail filter" interface seems to have broken. This problem is also present in the sid version (2.3.7.2-1). Mail filter is used to run the content of messages being stored or retrieved through an arbitrary process. The interface used for the external process is described here: https://wiki.dovecot.org/Plugins/MailFilter It is expected that the process will be called with the arguments specified in the configuration then supplied a message body on stdin, however since upgrading it seems that the arguments are not being correctly passed, instead being all jammed in to $1 and separated by tabs, rather than expanded in to argv. Even stranger the first few lines of the body of the message appear in argv rather than in stdin... These reproduction steps were carried out on a fresh install of Debian Buster with the "dovecot-core" package installed initially from stretch then upgraded to the buster version, however this behaviour has also been observed on stretch systems after upgrading to buster. To reproduce, drop this minimalised config in to /etc/dovecot/conf.d/repro.conf: # Minimal maildir setup for LDA first_valid_uid = 0 mail_location = maildir:~/Maildir userdb { driver = static args = allow_all_users=yes uid=mail gid=mail home=/tmp/%u } # Mail filter configuration mail_plugins = $mail_plugins mail_filter plugin { mail_filter = mail-filter read %u mail_filter_out = mail-filter write %u } service mail-filter { executable = script /usr/local/bin/mail-filter.sh user = dovecot unix_listener mail-filter { mode = 0666 } } And create the example script in /usr/local/bin/mail-filter.sh with executable permissions: #!/bin/bash echo "arguments were: $@" 1>&2 tempfile=$(mktemp) cat > "${tempfile}" cat "${tempfile}" rm "${tempfile}" This script simply logs the arguments it recieves, writes stdin to a file then retrieves it again from the file. Here's a sample session of me using dovecot-lda to pass a message through this script, then retrieve it again with doveadm: root@scratch-b6fd8bdd:~# /usr/lib/dovecot/dovecot-lda -d fincham@scratch-b6fd8bdd -f 'Test <scratch-b6fd8bdd>' < /root/test.eml root@scratch-b6fd8bdd:~# doveadm fetch -u 'fincham@scratch-b6fd8bdd' hdr subject Test hdr: To: Test <fincham@scratch-b6fd8bdd> From: Test <fincham@scratch-b6fd8bdd> Subject: This is the test e-mail root@scratch-b6fd8bdd:~# tail /var/log/syslog | grep mail-filter Sep 5 00:07:48 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: write fincham@scratch-b6fd8bdd Sep 5 00:07:50 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: read fincham@scratch-b6fd8bdd However after upgrading dovecot to the buster version this process no longer works, and the logged argv of the example script is very strange: root@scratch-b6fd8bdd:~# apt dist-upgrade Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done The following NEW packages will be installed: liblua5.3-0 libsodium23 ssl-cert The following packages will be upgraded: dovecot-core [...] root@scratch-b6fd8bdd:~# /usr/lib/dovecot/dovecot-lda -d fincham@scratch-b6fd8bdd -f scratch-b6fd8bdd < /root/test.eml Aborted root@scratch-b6fd8bdd:~# doveadm fetch -u 'fincham@scratch-b6fd8bdd' hdr subject Test hdr: Hello! doveadm(fincham@scratch-b6fd8bdd): Error: Mailbox INBOX: UID=1: read() failed: Cached message size larger than expected (115 > 7, box=INBOX, UID=1) (read reason=mail stream) doveadm(fincham@scratch-b6fd8bdd): Error: Corrupted record in index cache file /tmp/fincham(a)scratch-b6fd8bdd/Maildir/dovecot.index.cache: UID 1: Broken physical size in mailbox INBOX: read() failed: Cached message size larger than expected (115 > 7, box=INBOX, UID=1) doveadm(fincham@scratch-b6fd8bdd): Error: read() failed: Cached message size larger than expected (115 > 7, box=INBOX, UID=1) doveadm(fincham@scratch-b6fd8bdd): Error: fetch(hdr) failed for box=INBOX uid=1: read() failed: Cached message size larger than expected (115 > 7, box=INBOX, UID=1) root@scratch-b6fd8bdd:~# tail /var/log/syslog | grep mail-filter Sep 5 00:07:48 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: write fincham@scratch-b6fd8bdd Sep 5 00:07:50 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: read fincham@scratch-b6fd8bdd Sep 5 00:12:11 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: write#011fincham@scratch-b6fd8bdd#011 To: Test <fincham@scratch-b6fd8bdd> From: Test <fincham@scratch-b6fd8bdd> Subject: This is the test e-mail Sep 5 00:12:14 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: read#011fincham@scratch-b6fd8bdd#011 To: Test <fincham@scratch-b6fd8bdd> From: Test <fincham@scratch-b6fd8bdd> Subject: This is the test e-mail -- Package-specific info: dovecot configuration --------------------- # 2.3.4.1 (f79e8e7e4): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.4 () # OS: Linux 4.19.0-5-cloud-amd64 x86_64 Debian 10.0 # Hostname: scratch-b6fd8bdd first_valid_uid = 0 mail_location = maildir:~/Maildir mail_plugins = " mail_filter" mail_privileged_group = mail namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } plugin { mail_filter = mail-filter read %u mail_filter_out = mail-filter write %u } service mail-filter { executable = script /usr/local/bin/mail-filter.sh unix_listener mail-filter { mode = 0666 } user = dovecot } ssl = no userdb { driver = passwd } userdb { args = allow_all_users=yes uid=mail gid=mail home=/tmp/%u driver = static } -- System Information: Debian Release: 10.0 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 4.19.0-5-cloud-amd64 (SMP w/2 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages dovecot-core depends on: ii adduser 3.118 ii libapparmor1 2.13.2-10 ii libbz2-1.0 1.0.6-9.1 ii libc6 2.28-10 ii libexttextcat-2.0-0 3.4.5-1 ii libicu63 63.1-6 ii liblua5.3-0 5.3.3-1.1 ii liblz4-1 1.8.3-1 ii liblzma5 5.2.4-1 ii libpam-runtime 1.3.1-5 ii libpam0g 1.3.1-5 ii libsodium23 1.0.17-1 ii libssl1.1 1.1.1c-1 ii libstemmer0d 0+svn585-1+b2 ii libwrap0 7.6.q-28 ii lsb-base 10.2019051400 ii openssl 1.1.1c-1 ii ssl-cert 1.0.39 ii ucf 3.0038+nmu1 ii zlib1g 1:1.2.11.dfsg-1 dovecot-core recommends no packages. Versions of packages dovecot-core suggests: pn dovecot-gssapi <none> pn dovecot-imapd <none> pn dovecot-ldap <none> pn dovecot-lmtpd <none> pn dovecot-lucene <none> pn dovecot-managesieved <none> pn dovecot-mysql <none> pn dovecot-pgsql <none> pn dovecot-pop3d <none> pn dovecot-sieve <none> pn dovecot-solr <none> pn dovecot-sqlite <none> pn dovecot-submissiond <none> ii ntp 1:4.2.8p12+dfsg-4 Versions of packages dovecot-core is related to: ii dovecot-core [dovecot-common] 1:2.3.4.1-5+deb10u1 pn dovecot-dev <none> pn dovecot-gssapi <none> pn dovecot-imapd <none> pn dovecot-ldap <none> pn dovecot-lmtpd <none> pn dovecot-managesieved <none> pn dovecot-mysql <none> pn dovecot-pgsql <none> pn dovecot-pop3d <none> pn dovecot-sieve <none> pn dovecot-sqlite <none> -- no debconf information ***************************** And here it is on 2.4 from git: Sep 5 02:18:10 scratch-b6fd8bdd dovecot: master: Dovecot v2.4.devel () starting up for imap, pop3, lmtp Sep 5 02:18:10 scratch-b6fd8bdd systemd[1]: Started LSB: Dovecot init script. Sep 5 02:18:12 scratch-b6fd8bdd dovecot: mail-filter: Error: arguments were: write#011fincham@scratch-b6fd8bdd#011 To: Test <fincham@scratch-b6fd8bdd> From: Test <fincham@scratch-b6fd8bdd> Subject: This is the test e-mail Sep 5 02:18:12 scratch-b6fd8bdd dovecot: lda(fincham@scratch-b6fd8bdd)<4213><94f8BWRwcF11EAAA/w3Ckw>: Panic: file ostream.c: line 201 (o_stream_flush): assertion failed: (stream->stream_errno != 0) Sep 5 02:18:12 scratch-b6fd8bdd dovecot: lda(fincham@scratch-b6fd8bdd)<4213><94f8BWRwcF11EAAA/w3Ckw>: Error: Raw backtrace: /usr/lib/dovecot/libdovecot.so.0(+0xef5fb) [0x7f85ed0715fb] -> /usr/lib/dovecot/libdovecot.so.0(+0xef661) [0x7f85ed071661] -> /usr/lib/dovecot/libdovecot.so.0(+0x4e808) [0x7f85ecfd0808] -> /usr/lib/dovecot/libdovecot.so.0(+0x52ec1) [0x7f85ecfd4ec1] -> /usr/lib/dovecot/libdovecot-storage.so.0(maildir_save_finish+0x96) [0x7f85ed1b24d6] -> /usr/lib/dovecot/libdovecot-lda.so.0(+0x4395) [0x7f85ed294395] -> /usr/lib/dovecot/libdovecot-storage.so.0(mailbox_save_finish+0x82) [0x7f85ed189e52] -> /usr/lib/dovecot/libdovecot-storage.so.0(mail_storage_copy+0xd9) [0x7f85ed17c409] -> /usr/lib/dovecot/libdovecot-storage.so.0(maildir_copy+0x52) [0x7f85ed1aea02] -> /usr/lib/dovecot/libdovecot-lda.so.0(+0x4221) [0x7f85ed294221] -> /usr/lib/dovecot/libdovecot-storage.so.0(+0x5c1bc) [0x7f85ed18a1bc] -> /usr/lib/dovecot/libdovecot-lda.so.0(mail_deliver_save+0x1b0) [0x7f85ed295390] -> /usr/lib/dovecot/libdovecot-lda.so.0(mail_deliver+0x2f6) [0x7f85ed295ad6] -> /usr/libexec/dovecot/dovecot-lda(main+0x81b) [0x560cba869f4b] -> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb) [0x7f85ecdde09b] -> /usr/libexec/dovecot/dovecot-lda(_start+0x2a) [0x560cba86a65a]

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