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Dovecot and certificates/keys on PKCS11 smartcards/HSMs
by Graham Leggett 16 Nov '21

16 Nov '21

Hi all, To configure SSL on dovecot using certificates and keys in files on disk, you specify the following: # Preferred permissions: root:root 0400 ssl_cert = </etc/ssl/dovecot.pem ssl_key = </etc/ssl/dovecot.pem Is there a syntax that will allow a certificate and key to be specified on a smartcard/HSM, as is possible (for example) for httpd at https://httpd.apache.org/docs/trunk/mod/mod_ssl.html#sslcertificatefile: # Example use of a certificate and private key from a PKCS#11 token: SSLCertificateFile "pkcs11:token=My%20Token%20Name;id=45” Regards, Graham —

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Bug report: Global Mailbox UID mismatch on replication when upgrading from 2.3.13 to 2.3.17
by Dennis Højgaard | Powerhosting Support 16 Nov '21

16 Nov '21

Hi. We use dovecot for replication on two dovecot nodes (using Maildir). Worked perfectly until upgrading from 2.3.13 to 2.3.17. I found out about it a couple of days after where Queued 'full resync' requests had gone up. ANd then i saw some failed requests. But nothing in the log. I found out which users having trouble and saw that it was new user so i ran doveadm sync manually and got the following error: doveadm(2849817): Warning: Mailbox changes caused a desync. You may want to run dsync again: Remote lost mailbox GUID 38e69e0ba98d936142ac29004e3fea09 (maybe it was just deleted?) So i found out that dovecot-uidlist had a mismatch on the Global Mailbox UID, so global mailbox uid is not the same on both servers. I don't know if there is something that has changed with regards to how this GUID is generated, because when i look at old mailboxes they are always identical on both servers. I fix this issue manually by editing dovecot-uidlist on one of the servers making the global mailbox uid on both servers identical, and then run force-resync. This works, but i guess something has changed. -- Dennis Højgaard Powerhosting Support *t:* +45 7222 4457 |*e:* dh(a)powerhosting.dk |*w:* https://powerhosting.dk

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Subfolder in sieve not working as expected
by Kees van Vloten 16 Nov '21

16 Nov '21

On 15-11-2021 23:04, dovecot(a)ptld.com wrote: >> On 11-15-2021 3:46 pm, Kees van Vloten wrote: >> >> I am trying to move incoming mails into subfolders with this sieve >> script: >> >> require ["fileinto", "variables", "mailbox"]; >> if header :matches "Delivered-To" "*@*" >> { >> fileinto :create "INBOX/${2}"; >> } > > I am not using variables and my folders are pre-created. But just to > give you a starting point, this is what works using maildir++ format > with default directory layout. > https://doc.dovecot.org/configuration_manual/mail_location/Maildir/ > > require ["fileinto"]; > # rule:[Dovecot] > if header :contains "sender" "@dovecot.org" > { > fileinto "INBOX.Dovecot"; > } I have seen that working in the past :-) I switched to LAYOUT=fs recently because of the limitations of the dot as a folder separator (now I can have the domain-name as a folder-name). I found a nice description about folder and namespace issues here: https://forum.hestiacp.com/t/character-not-allowed-in-mailbox-name/566/4 But somehow the sieve implementation does not seem to work properly with LAYOUT=fs. What a good approach to further analyze this issue?

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[Move mailboxes] 2.2.13 -> 2.3.13: Stuck on certificate verification
by phren＠ist-einmalig.de 15 Nov '21

15 Nov '21

Hi, I'm about to move all mailboxes from an old machine - running Dovecot 2.2.13 - to a new machine - running Dovecot 2.3.13 (89f716dc2). Cause the new machine is in a different location I must use SSL encryption. I followed the guide's I found, but I stuck on certificate verification: $ doveadm backup -Ru <user> tcps:<host>:12354 doveadm(<user>): Info: Received invalid SSL certificate: unable to get local issuer certificate: /CN=<host> (check ssl_client_ca_* settings?) doveadm(<user>): Error: doveadm server disconnected before handshake: Received invalid SSL certificate: unable to get local issuer certificate: /CN=<host> (check ssl_client_ca_* settings?) doveadm(<user>): Error: Disconnected from remote: Received invalid SSL certificate: unable to get local issuer certificate: /CN=<host> (check ssl_client_ca_* settings?) On port 12354 the server sends an incomplete certificate chain, whereas on port 993 everything is fine. I read that the settings - ssl_client_ca_dir - ssl_client_ca_file are not used on certificate verification for port 12354, one should use the setting ssl_ca Here are the non-default setting on the client side: $ dovecot -n # 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.13 (cdd19fe3) # OS: Linux 5.10.0-9-amd64 x86_64 Debian 11.1 ... ssl_ca = </etc/dovecot/dovecot_imap_chain.crt ssl_cert = </etc/ssl/letsencrypt.org/<host>.combine.crt ssl_cipher_list = EDH+aRSA:EECDH+aRSA+AESGCM:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH:+AES256:!aNULL:!eNULL:!LOW:!MEDIUM:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!ECDSA:!CAMELLIA ssl_client_ca_dir = /etc/ssl/certs ssl_client_ca_file = /etc/ssl/certs/ca-certificates.crt ... ssl_min_protocol = TLSv1.2 ssl_prefer_server_ciphers = yes ... verbose_ssl = yes ssl_verify_client_cert = yes According to https://doc.dovecot.org/configuration_manual/dovecot_ssl_configuration/ the setting ssl_ca should contain Issuing CA cert Issuing CA CRL Intermediate CA cert Intermediate CA CRL Root CA cert Root CA CRL But how do I build this file? I tried root certificate, root + intermediate certificate and root + intermediate + signed certificate. None of them made it work... I'm completely stuck on how to make certificate verification work. Can anyone give me a hint? Thanks in advance.

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Strategies for protecting IMAP (e.g. MFA)
by Kees van Vloten 14 Nov '21

14 Nov '21

Apart from a really nice firewall firehol also supplies a good set of ip-blacklists. For public exposure of email ports, I am using the combination of firehol-firewall, firehol-blacklist, fail2ban and a whitelist based on geo-ip. The mail-client ports exposed are 993 and 465, because starttls is considered flawed nowadays: https://nostarttls.secvuln.info/) Full access from any IP (except firehol-blacklist and fail2ban) is possible over VPN (openvpn) with MFA (privacyidea). Privacyidea also supplies a mobile-app compatible with a.o. TOTP and HOTP but it provides a more secure way of enrollment (2-step). Thanks for pointing at crowdsec.net, will see if it can tighten security further in cooperation with the above. - Kees On 14-11-2021 11:33, infoomatic wrote: > I will throw in a few interesting projects which have kept my small > servers safe: > > *) firehol.org > > *) crowdsec.net > > *) www.fail2ban.org > > Have a look at those interesting projects! > > > On 13.11.21 22:16, Tyler Montney wrote: >> With the world of ransomware as it is today (aka attacks seem more >> vicious and commonplace), anything I expose to WAN must have >> additional protection. I've seen a few posts to this list on it. The >> only thing that helped was that Dovecot supports OAuth. Through OAuth >> I figure I could implement MFA. However, I'd have to host my own >> identity server. From there, Thunderbird supports OAuth so that should >> work. >> >> Since this is getting increasingly complicated, I wanted to ask before >> going further. What do you all do? Any recommendations?

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Re: Strategies for protecting IMAP (e.g. MFA)
by Marc 14 Nov '21

14 Nov '21

Don't use email addresses as login ;) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -. F1 Outsourcing Development Sp. z o.o. Poland t: +48 (0)12 4207 835 e: marc(a)f1-outsourcing.eu

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IPv4/v6 based access checking and logging
by Lefteris Tsintjelis 13 Nov '21

13 Nov '21

Hi, I am currently using postfix/dovecot with postfix admin and I track the last login date already by using this: https://doc.dovecot.org/configuration_manual/lastlogin_plugin/ Besides last login date, I would like to also implement IPv4 and IPv6 last login tracking also and if possible, IP based login checking. Is post-login scripting the best most efficient way to go? Regards, Lefteris

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2.3.17 update breaks dsync over tcps: Received invalid SSL certificate unable to get certificate CRL
by Salatiel Filho 12 Nov '21

12 Nov '21

Hi, I have updated dovecot from 2.3.16 (working flawless ) to 2.3.17 ( both Centos8 - community repo ) . Now dsync does not work anymore, logs shows: dovecot[30398]: doveadm(vmail): Error: Disconnected from remote: Received invalid SSL certificate: unable to get certificate CRL: /CN=imap.signed.with.my.own.ca(check ssl_client_ca_* settings?) I have a certificate signed by my "own CA". Both hosts trust my CA, and as I told previously, the configuration works just fine on 2.3.16. I really was not expecting that a minor update would break things, but 2.3.17 appears to have broken the setup for some people here in the maillists. Is there a workaround for this? I have tried to set ssl_require_crl = no , but nothing changed. I have: service doveadm { inet_listener { port = 26 ssl = yes } } ssl = required ssl_ca = </etc/ssl/certs/mail-cluster-communication_ca.pem ssl_cert = </etc/ssl/certs/mail-cluster-communication.crt ssl_key = # hidden, use -P to show it Thanks! Atenciosamente/Kind regards, Salatiel

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after replication with compression quotas are wrong
by Arnaud Abélard 12 Nov '21

12 Nov '21

Hello, We are very long time happy dovecot users (since 2008 at least). We have around 90k mailboxes and since we had to move away from our NAS storage to a ceph storage I jumped on the opportunity to enable compression with the zlib plugin and dovecot's replication mecanism. We are using debian's dovecot 2.2.27 packages on production and our new server is running dovecot's own ce-2.3.17 packages. On the production server everything works fine but on the new server, replicated mailboxes' quota is all wrong: on production: # doveadm quota get -u dummy-c-1 Quota name Type Value Limit % Quota Utilisateur STORAGE 660026 976563 67 Quota Utilisateur MESSAGE 8651 - 0 on new server: doveadm quota get -u dummy-c-1 Quota name Type Value Limit % Quota Utilisateur STORAGE 1125251 976563 115 Quota Utilisateur MESSAGE 16646 - 0 If I add all the S flag from the filenames n both servers I get exactly the same usage, which is coherent with the quota on the production server: # find . -type f | grep 'S=' | awk -F'S=' '{print $2}' | awk -F',' '{print $1}' | awk -F':' '{print $1}' | paste -sd+ | bc -l 675865938 And I have exactly the same amountof mails on the two server, the replication works as expected, no unwanted duplication of mails occurs. Of course, I've tried to ask dovecot to recalculate quotas with doveadm quota recalc -u <username>, but it doesn't fix the problem. What am I missing? Thanks, Arnaud PS: Here is my doveconf -n output: # 2.3.17 (e2aa53df5b): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.17 (054dddfa) # OS: Linux 4.19.0-18-amd64 x86_64 Debian 10.11 # Hostname: gromel-test auth_cache_size = 10 k auth_verbose = yes disable_plaintext_auth = no doveadm_password = # hidden, use -P to show it hostname = gromel1.univ-nantes.prive lda_mailbox_autosubscribe = yes listen = * log_timestamp = "%Y-%m-%d %H:%M:%S " login_trusted_networks = (...) mail_gid = 5000 mail_location = maildir:%h mail_plugins = quota zlib notify replication mail_privileged_group = vmail mail_uid = 5000 maildir_stat_dirs = yes maildir_very_dirty_syncs = yes managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext namespace { inbox = yes location = prefix = INBOX. separator = . type = private } passdb { args = /etc/dovecot/dovecot-ldap.conf driver = ldap } plugin { quota = maildir:Quota Utilisateur quota_exceeded_message = Cet utilisateur a dépassé son quota, votre message n'a pu lui être livré. quota_full_tempfail = yes quota_rule = *:storage=1000M quota_rule2 = INBOX.Trash:storage=+100M sieve = ~/dovecot.sieve sieve_dir = ~/sieve sieve_extensions = -vacation sieve_global_dir = /var/lib/dovecot/sieve/global/ sieve_max_redirects = 1 zlib_save = gz zlib_save_level = 6 } postmaster_address = postmaster@<snip> protocols = imap pop3 sieve replication_max_conns = 50 service auth { client_limit = 49452 unix_listener auth-userdb { group = vmail mode = 0600 user = vmail } user = root } service dict { unix_listener dict { mode = 0600 user = vmail } } service doveadm { inet_listener { port = 12345 } } service imap-login { process_min_avail = 8 service_count = 0 user = mail } service imap { executable = imap process_limit = 16384 vsz_limit = 2 G } service managesieve-login { inet_listener sieve { port = 4190 } process_min_avail = 8 service_count = 0 user = mail vsz_limit = 2 G } service managesieve { drop_priv_before_exec = yes process_limit = 16384 } service pop3-login { process_min_avail = 8 service_count = 0 user = mail } service pop3 { drop_priv_before_exec = yes process_limit = 16384 } ssl = no userdb { args = /etc/dovecot/dovecot-ldap.conf driver = ldap } verbose_proctitle = yes protocol imap { mail_max_userip_connections = 50 mail_plugins = quota zlib notify replication imap_quota zlib } protocol pop3 { mail_plugins = quota zlib notify replication } protocol sieve { mail_max_userip_connections = 10 } protocol lda { mail_plugins = quota zlib notify replication sieve zlib } -- Arnaud Abélard Responsable pôle Système et Stockage Service Infrastructures DSIN Université de Nantes -

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2.3.17: Panic on LMTP deliveries
by Michael Glaus 12 Nov '21

12 Nov '21

Hello Since the doevcot update to 2.3.17 i get a panic if a mail is delivered with lmtp. In the logs i get these messages: lmtp(rcpt(a)example.com)<21067><AtxaKh+hi2FLUgAAwujwpQ>: Error: lmtp-server: conn 10.0.0.105:52981 [1]: rcpt rcpt(a)example.com: duplicate db: User rcpt(a)example.com doesn't have home dir set, disabling duplicate database lmtp(rcpt(a)example.com)<21067><AtxaKh+hi2FLUgAAwujwpQ>: Panic: file imem.c: line 65 (i_strconcat): assertion failed: (str1 != NULL) lmtp(rcpt(a)example.com)<21067><AtxaKh+hi2FLUgAAwujwpQ>: Fatal: master: service(lmtp): child 21067 killed with signal 6 (core dumped) In the running config userdb does not return the field “home” and therefor a user does not have a “mail_home” only a “mail_location”. If i change the config to provide a “mail_home” it works, but due to the directory structure i can not change this yet. Best regards Michael Glaus Junior System Administrator -- Hostpoint AG Neue Jonastrasse 60 | 8640 Rapperswil-Jona | Schweiz michael.glaus(a)hostpoint.ch | www.hostpoint.ch

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