January 2021 - dovecot

Ubuntu packages
by Aki Tuomi 06 Jan '21

06 Jan '21

Hi! Since Ubuntu 20.04 LTS is nowadays available, we have dropped 16.04 support from 2.3.13 as per policy of supporting two latest releases of operating system. Dovecot 2.3.11.3 is latest version we provide packages for 16.04. Please find Ubuntu 20.04 packages at https://repo.dovecot.org/ Kind regards, Aki Tuomi Open-Xchange oy

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Imapsieve FLAG cause executes a pipe call twice
by DocMAX 06 Jan '21

06 Jan '21

I have this setup: imapsieve_mailbox1_name = * imapsieve_mailbox1_causes = FLAG imapsieve_mailbox1_before = file:~/sieve/learn-flag.sieve Now if i change the SPAM flag i can see: Dez 24 14:49:08 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: mailbox Junk-E-Mail/dziennik.pl: FLAG event (changed flags: NonJunk) Dez 24 14:49:08 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: Matched static mailbox rule [1] Dez 24 14:49:08 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: mailbox Junk-E-Mail/dziennik.pl: FLAG event (changed flags: Junk) Dez 24 14:49:08 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: Matched static mailbox rule [1] Dez 24 14:49:11 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: mailbox Junk-E-Mail/dziennik.pl: FLAG event (changed flags: Junk) Dez 24 14:49:11 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: Matched static mailbox rule [1] Dez 24 14:49:11 server dovecot[219886]: imap(docmax)<221469><BStCETa3fMzAqAEB>: Debug: imapsieve: mailbox Junk-E-Mail/dziennik.pl: FLAG event (changed flags: NonJunk) And my script is: require [ "variables" , "imap4flags", "fileinto", "vnd.dovecot.pipe", "copy", "imapsieve", "vnd.dovecot.execute" ]; if hasflag :is "Junk" { pipe :copy "rspam-spam"; stop; } if hasflag :is "NonJunk" { pipe :copy "rspam-ham"; stop; } Dez 24 15:05:24 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam Dez 24 15:05:24 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-ham Dez 24 15:05:27 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam Dez 24 15:05:27 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam Dez 24 15:05:32 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam Dez 24 15:05:32 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-ham Dez 24 15:05:36 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam Dez 24 15:05:36 server dovecot[222484]: imap(docmax)<224089></EW5RDa3UMPAqAEB>: Debug: sieve: action pipe: running program: rspam-spam I espected to have only ONE pipe when i change flag (in Thunderbird). Instead i get multiple calls. Why is that and how can i fix it? Regards, DocMAX

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Dovecot Folder and file permissions.
by Thomas Strike 06 Jan '21

06 Jan '21

While working with adding a website to apache on my server something caused a blanket resetting of all file permissions on the server to apache:apache. I have most of the server running again but my mail services is another story. I have configured vmail on a Postfix with Dovecot and mariadb install. What I need is help with reestablishing the correct file and folder permissions that dovecot uses. The following is my configuration; # OS: Linux 4.18.0-147.3.1.el8_1.x86_64 x86_64 CentOS Linux release 8.1.1911 (Core) xfs # Dovecot version# 2.2.36 (1f10bfa63) # Hostname: sleepyvalley auth_mechanisms = plain login mail_home = /var/vmail/%d/%n mail_location = maildir:/var/vmail/%d/%n mail_privileged_group = mail mail_uid = vmail mbox_write_locks = fcntl 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 { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } passdb { args = scheme=CRAM-MD5 username_format=%u /etc/dovecot/users driver = passwd-file } postmaster_address = postmaster(a)sleepyvalley.net service auth-worker { user = vmail } service auth { unix_listener /var/spool/postfix/private/auth { mode = 0666 } unix_listener auth-userdb { mode = 0666 user = vmail } } service lmtp { unix_listener /var/spool/postfix/private/dovecot-lmtp { group = postfix mode = 0666 user = postfix } } ssl_cert = </etc/letsencrypt/live/mail.sleepyvalley.net/fullchain.pem ssl_cipher_list = PROFILE=SYSTEM ssl_key = # hidden, use -P to show it userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } userdb { args = uid=vmail gid=vmail home=/home/vmail/%d/%n driver = static } I really need help with this, thanks.

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CVE fixed?
by Oren Savich 05 Jan '21

05 Jan '21

Hi, I wanted to know if you fixed CVE-2020-24386 & CVE-2020-25275. If so, in what commits? thanks in advance!

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Panic file istream-seekable.c
by Eric Mauger 04 Jan '21

04 Jan '21

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set up for Dovecot redundancy -- store on edge server only if link to backofc server is down, otherwise deliver to final dest?
by PGNet Dev 04 Jan '21

04 Jan '21

I run Postfix + Dovecot. Currently, I've got a cloud-instance of Postfix that handles all the anti-spam/auth/routing. On successful 'pass', it resends email -- over a VPN link -- to a *local* Postfix instance, which then LMTP-delivers to a Dovecot instance on the same box. Works great. I'd like to set up some IMAP redundancy, so that if the VPN link is down for any reason, mail is stored/accessible, and -- eventually -- correctly (re)delivered to the local Dovecot instance when the link's up again. The goal state I'm considering looks like: @cloud Postfix LMTP delivery from Postfix to "Dovecot1" @local LMTP (re)delivery from "Dovecot1", @cloud, to "Dovecot2" IDEALLY, no IMAP mail should ever be persistently stored on the @cloud Dovecot instance -- unless the VPN link is down. Then, when the VPN link is up again, the @cloud-stored IMAP mail should me 'moved' to the @local instance. I.e., I do _not_ want a replicated store. My question is how transparent/automated can this be done? I'd guess that somewhere in Dovecot's config I need logic that provides the conditional delivery to just @cloud vs 'all the way' to @local ... Any suggestions as to how to put this VPN-conditional redundancy in place?

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deleting maildata from virtual users
by Alexander Rivanykov 04 Jan '21

04 Jan '21

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CVE-2020-25275: MIME parsing crashes with particular messages
by Aki Tuomi 04 Jan '21

04 Jan '21

Open-Xchange Security Advisory 2021-01-04 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-4113 (Bug ID) Vulnerability type: CWE-20: Improper Input Validation Vulnerable version: 2.3.11-2.3.11.3 Vulnerable component: lda, lmtp, imap Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.13 Vendor notification: 2020-09-10 Solution date: 2020-09-14 Public disclosure: 2021-01-04 CVE reference: CVE-2020-25275 CVSS: 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) Researcher credit: Innokentii Sennovskiy (Rumata888) from BI.ZONE Vulnerability Details: Mail delivery / parsing crashed when the 10 000th MIME part was message/rfc822 (or if parent was multipart/digest). This happened due to earlier MIME parsing changes for CVE-2020-12100. Risk: Malicious sender can crash dovecot repeatedly by sending / uploading message with more than 10 000 MIME parts. Workaround: These are usually dropped by MTA, where the mitigation can also be applied. Solution: Operators should update to 2.3.13 or later version.

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TLS problem with iOS 9 Mail clients
by Maik Musall 02 Jan '21

02 Jan '21

Hi everyone, recently I migrated my mail server from an Ubuntu 16.04 box to an Ubuntu 20.04 box, so from dovecot 2.2.22 to 2.3.7.2, and to openssl 1.1.1.f. While everything else works fine, I have one important user stuck on an iOS 9 device that I need to support for a while longer, with which the IMAP TLS handshake keeps failing. From the logs: TLS handshaking: SSL_accept() failed: error:14209102:SSL routines:tls_early_post_process_client_hello:unsupported protocol I didn’t find a debug option to dump the TLS handshake details, so I analyzed a packet dump and found the following capabilities and cipher suites offered by the client: Transport Layer Security TLSv1 Record Layer: Handshake Protocol: Client Hello Content Type: Handshake (22) Version: TLS 1.0 (0x0301) Length: 149 Handshake Protocol: Client Hello Handshake Type: Client Hello (1) Length: 145 Version: TLS 1.0 (0x0301) Random: 5fef787ac06215d0a4edefd17602fadf409ab0512e04e62ade6192f2499f4896 Session ID Length: 0 Cipher Suites Length: 50 Cipher Suites (25 suites) Cipher Suite: TLS_EMPTY_RENEGOTIATION_INFO_SCSV (0x00ff) Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 (0xc024) Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 (0xc023) Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (0xc00a) Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (0xc009) Cipher Suite: TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA (0xc008) Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (0xc028) Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (0xc027) Cipher Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (0xc014) Cipher Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (0xc013) Cipher Suite: TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA (0xc012) Cipher Suite: TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (0x006b) Cipher Suite: TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (0x0067) Cipher Suite: TLS_DHE_RSA_WITH_AES_256_CBC_SHA (0x0039) Cipher Suite: TLS_DHE_RSA_WITH_AES_128_CBC_SHA (0x0033) Cipher Suite: TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA (0x0016) Cipher Suite: TLS_RSA_WITH_AES_256_CBC_SHA256 (0x003d) Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA256 (0x003c) Cipher Suite: TLS_RSA_WITH_AES_256_CBC_SHA (0x0035) Cipher Suite: TLS_RSA_WITH_AES_128_CBC_SHA (0x002f) Cipher Suite: TLS_RSA_WITH_3DES_EDE_CBC_SHA (0x000a) Cipher Suite: TLS_ECDHE_ECDSA_WITH_RC4_128_SHA (0xc007) Cipher Suite: TLS_ECDHE_RSA_WITH_RC4_128_SHA (0xc011) Cipher Suite: TLS_RSA_WITH_RC4_128_SHA (0x0005) Cipher Suite: TLS_RSA_WITH_RC4_128_MD5 (0x0004) Compression Methods Length: 1 Compression Methods (1 method) Compression Method: null (0) Extensions Length: 54 Extension: server_name (len=19) Type: server_name (0) Length: 19 Server Name Indication extension Extension: supported_groups (len=8) Extension: ec_point_formats (len=2) Type: ec_point_formats (11) Length: 2 EC point formats Length: 1 Elliptic curves point formats (1) EC point format: uncompressed (0) Extension: status_request (len=5) Type: status_request (5) Length: 5 Certificate Status Type: OCSP (1) Responder ID list Length: 0 Request Extensions Length: 0 Extension: signed_certificate_timestamp (len=0) Type: signed_certificate_timestamp (18) Length: 0 I already tweaked the dovecot-ssl config down with "ssl_min_protocol = TLSv1” and included ECDHE-ECDSA-AES256-SHA in the cipher list, but the client still won’t connect. Does anyone have an idea what else I could try? Thanks Maik

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LDA ignores virtual mailbox settings
by Toni Mueller 01 Jan '21

01 Jan '21

Hi, I have a Debian/Buster system with Postfix and Dovecot from the Debian repo, and with virtual users only (ie, no system users). These virtual users are having all of their uids, gids, homes and mail quota in an PostgreSQL database. The intent is to have postfix deliver the email via dovecot's LDA, so I can set quota on a per-user basis. But for some odd reason, Dovecot's LDA can't find the user data from the userdb, and then complains about not being able to write to /var/mail. The following example shows how things fail when delivering a message from Postfix's queue (therefore, the passdb failure is expected): In /etc/dovecot.conf, I have this, amongst other things: mail_location = maildir:~/Maildir:INBOX=~/Maildir passdb { driver = sql args = /etc/dovecot/dovecot-sql.conf.ext } userdb { driver = prefetch } userdb { driver = sql args = /etc/dovecot/dovecot-sql.conf.ext } protocol lda { mail_plugins = autocreate quota mail_log trash virtual notify } 16:04:16 postfix/qmgr[4970]: 8CD6CE072E: from=<user(a)example.com>, size=880, nrcpt=1 (queue active) 16:04:16 dovecot: auth: Debug: master in: USER#0111#011user(a)example.com#011service=lda 16:04:16 dovecot: auth: Debug: prefetch(user(a)example.com): passdb didn't return userdb entries, trying the next userdb 16:04:16 dovecot: auth: Debug: sql(user(a)example.com): SELECT '/path-to-mailboxen/' || virtual_users.home AS home, uid , gid , quota as quota_rule FROM virtual_users WHERE email = 'user(a)example.com' AND status = 'A' 16:04:16 dovecot: auth: Debug: userdb out: USER#0111#011user@example.com#011home=/path-to-mailboxen/example.com/user#011uid=12345#011gid=12345#011quota_rule=*:storage=0 ^^^^^^^^^^^^^^^^^^^^^^ This shows that the database lookup works. The intended effect should be that the message is delivered to /path-to-mailboxen/example.com/user/Maidir/new 16:04:16 dovecot: lda(user(a)example.com)<5291><DDxBHYCw6F+rFAAApiCoHg>: Error: setegid(privileged) failed: Operation not permitted 16:04:16 dovecot: lda(user(a)example.com)<5291><DDxBHYCw6F+rFAAApiCoHg>: Error: Mailbox INBOX: open(/var/mail/user(a)example.com) failed: Permission denied (euid=12345(mailbox) egid=12345(mailbox) missing +w perm: /var/mail, we're not in group 8(mail), dir owned by 0:8 mode=0775) ^^^^^^^^^^^^^^^^^^^^^^ And this shows that dovecot-lda just ignores the result. 16:04:16 dovecot: lda(user(a)example.com)<5291><DDxBHYCw6F+rFAAApiCoHg>: Error: Mailbox INBOX: Failed to autocreate mailbox: Mailbox INBOX: open(/var/mail/user(a)example.com) failed: Permission denied (euid=12345(mailbox) egid=12345(mailbox) missing +w perm: /var/mail, we're not in group 8(mail), dir owned by 0:8 mode=0775) 16:04:16 dovecot: lda(user(a)example.com)<5291><DDxBHYCw6F+rFAAApiCoHg>: msgid=<20201226224933.014608(a)laptop.example.com>: save failed to open mailbox INBOX: Mailbox INBOX: Failed to autocreate mailbox: Mailbox INBOX: open(/var/mail/user(a)example.com) failed: Permission denied (euid=12345(mailbox) egid=12345(mailbox) missing +w perm: /var/mail, we're not in group 8(mail), dir owned by 0:8 mode=0775) 16:04:16 postfix/pipe[5284]: 8CD6CE072E: to=<user(a)example.com>, orig_to=<userA(a)example2.com>, relay=dovecot, delay=62083, delays=62083/0.04/0/0.04, dsn=4.3.0, status=deferred (temporary failure) In /etc/postfix/master.cf, I have this to call it: dovecot unix - n n - - pipe flags=DRhu user=_mailbox argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${domain} -a ${recipient} I've tried strace-ing dovecot-lda, but it didn't really help me to understand why it discards the result of the userdb lookup. Can anyone please provide a cluebat, please? Thanks, Toni

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