July 2023 - dovecot - dovecot.org

Filtering by SASL auth mechanism
by Graham Leggett 26 Jul '23

26 Jul '23

Hi all, I want dovecot to behave differently depending on what SASL mechanism was used. Most specifically, if EXTERNAL, I want auth_ssl_username_from_cert to be yes, but no otherwise. There is a filtering mechanism that supports protocol, remote, etc. https://doc.dovecot.org/configuration_manual/config_file/ Would it make sense to add a SASL mechanism filter like this: mechanism external { # … } Regards, Graha —

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SASL External and LDAP - Login attempt with empty password
by Graham Leggett 26 Jul '23

26 Jul '23

Hi all, I am trying to configure dovecot to accept SASL EXTERNAL authentication with a client certificate and no password. I have tried the following configuration: passdb { driver = ldap # Path for LDAP configuration file, see example-config/dovecot-ldap.conf.ext args = /etc/dovecot/dovecot-ldap-external.conf.ext mechanisms = external default_fields = noauthenticate=y } In the logs I see dovecot correctly negotiate SASL EXTERNAL, but eventually we reach this line and we fail: https://github.com/dovecot/core/blob/34a18f5a79bf7eca58e55aff3e1fe69468292d… Which is in turn reached by following this code: https://github.com/dovecot/core/blob/34a18f5a79bf7eca58e55aff3e1fe69468292d… In theory, if I understand this correctly, what is missing is a field to say “don’t try check any password”, which field is this supposed to be? “nopassword”? “noauthenticate”? I am happy to patch this, but need some guidance as what the correct approach is. Regards, Graham —

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Quota possibly overcomplicating, need sanity check?
by David Mehler 25 Jul '23

25 Jul '23

Hello, New setup and trying to get quotas going. It's a Dovecot/Postfix/Mariadb virtual user setup. In my db I have a varchar field called quota with a default value of 128. Here's what I have in dovecot configs for quota: # Plugins mail_plugins = acl mail_crypt quota service stats { fifo_listener stats-mail { user = vmail mode = 0644 } inet_listener { address = 127.0.0.1 port = 24242 } } # quota status service quota-status { executable = quota-status -p postfix unix_listener /var/spool/postfix/private/dovecot-quota { user = postfix group = postfix mode = 0660 } client_limit = 1 } # Quota warnings service quota-warning { executable = script /usr/local/bin/quota-warning.sh user = vmail unix_listener quota-warning { group = vmail mode = 0660 user = vmail } } plugin { quota = count:User quota quota2 = maildir:Shared quota:ns=public/ quota_max_mail_size = 100M # Required for 'count' quota driver quota_vsizes = yes quota_rule2 = Trash:storage=+10%% quota_rule = *:storage=1G quota_rule2 = Trash:storage=100M quota_rule3 = SPAM:ignore quota_warning = storage=100%% quota-warning +100 %u quota_warning2 = storage=95%% quota-warning +95 %u quota_warning3 = storage=80%% quota-warning +80 %u quota_warning4 = -storage=100%% quota-warning -100 %u # user is no longer over quota quota_exceeded_message = User %u has exhausted allowed storage space. quota_grace = 10%% # 10% is the default quota_status_success = DUNNO quota_status_nouser = DUNNO quota_status_overquota = "552 5.2.2 Mailbox is full" ## Stats ### how often to session statistics (must be set) stats_refresh = 30 secs ### track per-IMAP command statistics (optional) stats_track_cmds = yes } The protocol imap has the imap_quota plugin and protocol lmtp has the quota plugin. I've also got lmtp_rcpt_check_quota = yes mailbox_list_index = yes In my dovecot-sql.conf file my user query looks like this: user_query = SELECT concat('*:storage=', quota, 'M') AS quota_rule FROM accounts WHERE username = '%Ln' AND domain = '%Ld' AND sendonly = false; Postfix checks: check_policy_service unix:private/dovecot-quota Am I overcomplicating? Thanks. Dave.

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mail_crypt on existing mailstore
by David Mehler 25 Jul '23

25 Jul '23

Hello, I've got a pre-existing mailstore, it's a Postfix/Dovecot/Mariadb virtual-user setup, with users and mailboxes. I'd now like to get mail_crypt going. Can I do this with this existing store or if not how would I set this up? Thanks. Dave.

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subscription, dots and subscribe to shared folder.
by Julien Nadal 24 Jul '23

24 Jul '23

Hello; We were able to set up shared folders in a cluster (using dovecot as proxy on dedicated front-end servers, without using director) by following https://doc.dovecot.org/configuration_manual/shared_mailboxes/cluster_setup/. Here is our related conf on imap farms (dovecot v2.3.16 on Almalinux): namespaces: mail_location = maildir:~/Maildir namespace default { inbox = yes location = prefix = separator = / } namespace shared { list = children location = imapc:~/shared/%%u:INDEXPVT=~/shared-pvt/%%u prefix = shared/%%u/ separator = / subscriptions = no type = shared } imapc settings: imapc_features = fetch-bodystructure fetch-headers rfc822.size search modseq acl delay-login imapc_host = XXXXXX imapc_master_user = %{user} imapc_password = XXXXXX imapc_port = XXXXXX passdb { args = password=#hidden_use-P_to_show# userdb_namespace/shared/disabled=yes userdb_acl_user=%{auth_user} allow_nets=XXXXX/XX driver = static master = yes } dict { acl-mysql = mysql:/etc/dovecot/conf.d/dovecot-dict-sql.conf.ext } This way, a folder is created under ~/ : shared & shared-pvt : When user A shares a folder with B, B will find ~/shared/userA/sharedfolder I should mention that the user authentication (backend: mysql) uses the full email address as we are in a multi-tenant context. So the folder looks like ~/shared/usera(a)domain.tld/folder Since then, everything works perfectly, we can share and see the shared folders in the webmail (SOGo). Unfortunately, accessing these folders through an imap client (tested on Thunderbird and MSOutlook) is impossible because the subscription fails (the folder is listed, but the subscription doesn't seem to do anything). I could not find any relevant logs but I was able to confirm on the command line: I am able to view folder with LIST, subscribe with an "OK" output, but the folder is not listed with LSUB. So I could see that the subscribtion file in maildir shows incorrect entries: V 2 Sent Trash Drafts Junk shared/testuser1@sub domain tld/INBOX/folder The dots in the folder names are replaced by tabs. I was able to recover things by editing the file as follows: Sent Trash Drafts Junk shared/testuser1(a)sub.domain.tld/INBOX/folder This means that Maildir++ and V2 subscription can't handle dots in folders. I found a previous discussion: https://dovecot.org/pipermail/dovecot/2021-January/121233.html But the final advice can't be applied on our side: - changing LAYOUT to FS is not possible for us - we have already migrated the dot separator to slash - changing the layout only for shared namespaces does not solve the problem and totally breaks the access to shared folders. Thanks a lot for your advice Best regards Julien

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Outlook and IMAP Flags
by Laura Smith 22 Jul '23

22 Jul '23

Hi I've tried searching the internet, but the only thing I can find is a post on a MIcrosoft forum where a Microsoft reps claims flags are not supported on IMAP (I thought it was an RFC3501 feature ?). Anyway, I have a user who has Outlook/Windows on desktop and iOS (iPhone/iPad) for remote. On the iOS devices, the user can happily set flags against messages with zero issues. And indeed, when they set these flags, they are shown in Outlook. However if they attempt to set the flag in Outlook, nothing happens. Outlook continues showing the message as if it was unflagged. Any ideas ? Laura

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Exclude folders from fts xapian on a per-user basis
by Adam Kessel 21 Jul '23

21 Jul '23

Is there any way for a user to specify folders they want excluded from fts xapian indexing? Or can this only be done globally in /etc?

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Dovecot pigeon/sieve and SELinux
by Graham Leggett 21 Jul '23

21 Jul '23

Hi all, I am in the process of migrating a dovecot installation from RHEL8 to RHEL9, this time round I am trying to get everything to work in selinux enforcing mode. First error I am stuck on is as follows: Error: sieve: file storage: Failed to stat sieve storage path: stat(/var/lib/dovecot/sieve/vacation.sieve) failed: Permission denied (euid=377(vmail) egid=376(vmail) missing +x perm: /var/lib/dovecot, we're not in group 97(dovecot), dir owned by 97:97 mode=0750) It appears that the vmail user cannot access /var/lib/dovecot, because under RHEL9 the permissions are hidden to the world. [root@seawitch dovecot]# ls -al /var/lib/dovecot total 12 drwxr-x---. 3 dovecot dovecot 36 Jul 21 17:51 . Am I correct in interpreting the error message as meaning that /var/lib/dovecot/sieve is not a correct directory for global sieve scripts, and they need to go somewhere else? If they do need to go somewhere else, in the world of enforcing selinux, where do they go? While dovecot-selinux is documented, sieve is not mentioned: https://linux.die.net/man/8/dovecot_selinux So, let’s work around the above error by adding the vmail user to the dovvecot group. Is this even a good idea? /usr/sbin/usermod -a -G dovecot vmail Now we hit the next error: Error: sieve: file storage: Failed to stat sieve storage path: stat(/var/lib/dovecot/sieve/vacation.sieve) failed: Permission denied (euid=380(vmail) egid=378(vmail) missing +w perm: /var/lib/dovecot/sieve/vacation.sieve stat(/var/lib/dovecot/sieve/vacation.sieve) failed: Permission denied, dir owned by 0:0 mode=0755) This error is weird. Dovecot is trying to open the original vacation.sieve source file for write - why? We have pre-compiled all the global sieve scripts: [root@marcopolo ~]# ls -al /var/lib/dovecot/sieve/ total 36 drwxr-xr-x. 5 root root 4096 Jul 21 17:29 . drwxr-x---. 3 dovecot dovecot 36 Jul 21 17:29 .. -rwxr-xr-x. 1 root root 284 Jul 21 08:47 junk.sieve -rw-r--r--. 1 root root 277 Jul 21 17:29 junk.svbin -rwxr-xr-x. 1 root root 316 Jul 21 08:47 report-ham.sieve -rw-r--r--. 1 root root 476 Jul 21 17:29 report-ham.svbin -rwxr-xr-x. 1 root root 201 Jul 21 08:47 report-spam.sieve -rw-r--r--. 1 root root 382 Jul 21 17:29 report-spam.svbin drwxr-xr-x. 2 root root 6 Jul 21 08:47 sieve-execute drwxr-xr-x. 2 root root 6 Jul 21 08:47 sieve-filter drwxr-xr-x. 2 root root 6 Jul 21 08:47 sieve-pipe -rwxr-xr-x. 1 root root 309 Jul 21 08:47 vacation.sieve -rw-r--r--. 1 root root 558 Jul 21 17:29 vacation.svbin Is the error perhaps inaccurate, and it’s trying to open a temp file for write, failing (correctly, it has no business opening a temp file for write at this point), and then claiming the failure on the temp file is a failure on the source file? So to sum up: - In an SELinux world of Redhat, what directory do global sieve scripts go? - What permissions and selinux context are required on the global sieve scripts directory? Regards, Graham —

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IMAP account can't save any email with attachment
by Chris Thomas 20 Jul '23

20 Jul '23

Hi, I'm getting a curious problem where if I write a draft without an attachment and click save. It'll work without any issue at all. But if I do the same, then attach a file to the email, it'll sit there for a couple of minutes before timing out (I'm using thunderbird), it'll eventually give you a message saying "Your draft message was not copied to your drafts folder (Drafts) due to network or file access errors." I've got all of dovecots verbose logging turned on. I'm using dovecot as a submission server through to the postfix server to do the actual sending. All the logging is turned on there too. But I can't figure out what the problem is. Is there anything I can look for in the logs that will help me out? chris

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Re: Tons of imap-login processes despite client_limit very high
by Joseph Tam 20 Jul '23

20 Jul '23

https://www.mail-archive.com/dovecot%40dovecot.org/msg85850.html From: D D <pierre.alletru(a)gmail.com> > We're seeing a ton of imap-login processes running even when using high performance mode (https://doc.dovecot.org/admin_manual/login_processes/#high-performance-mode) According to the docs: > > "process_min_avail should be set to be at least the number of CPU cores in the system, so that all of them will be used. Otherwise new processes are created only once an existing one’s connection count reaches client_limit" > > We have process_min_avail=4, client_limit=0 and default_client_limit=200000. So we'd expect seeing only 4 imap-login processes serving a ton of connections each. Yet, we see thousands of imap-login processes (more than half of all the imap processes): > ... > > Is having so many imap-login processes normal with our config? Did we misunderstand the docs or is there something wrong here? > > > default_client_limit = 1048576 > default_process_limit = 200000 > > service imap-login { > # client_limit = 0 # default is 0 > # process_limit = 0 # default is 0 > service_count = 100 This service limit might be your culprit. I wrote about the strange interaction between service_count and process_limit here: https://www.mail-archive.com/dovecot%40dovecot.org/msg85850.html This gotcha should really be documented. Joseph Tam <jtam.home(a)gmail.com>

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