September 2024 - dovecot

Correct permissions for global sieve scripts
by Richard 16 Sep '24

16 Sep '24

Hi there, I've set up dovecot via global sieve scripts to send mails that a user manually moved to their junk directory to rspamd to learn them as spam (and learn messages as ham if they are moved out of it). I thought I had it all properly set up, but I'm now again seeing log messages like this: Sep 15 13:01:00 dovecot[523226]: imap(username)<823661><4+8RXyYi2L9/AAAB>: Error: sieve: failed to execute to program `rspamd-learn-spam.sh': refer to server log for more information. [2024-09-15 13:01:00] Sep 15 13:01:00 dovecot[523226]: imap(username)<823661><4+8RXyYi2L9/AAAB>: Error: sieve: Execution of script /etc/dovecot/sieve/global/learn-spam.sieve failed The content of learn-spam.sieve is this: require ["vnd.dovecot.pipe", "copy", "imapsieve"]; pipe :copy "rspamd-learn-spam.sh"; And the content of rspamd-learn-spam.sh is this: #!/bin/sh exec /usr/bin/rspamc learn_spam All the necessary files are located in /etc/dovecot/sieve/global and are owned by dovecot:dovecot with rw, r, r permissions. Also, I have compiled the .sieve files with sievec, the resulting .svbin files have the same permissions and ownership. What am I doing wrong? I don't see any further "server log" that will tell me more information. I'm using dovecot 2.3.19.1 (9b53102964) on Debian 12.7 Best Richard

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Allowing parallel read-only requests via doveadm http api
by Kevin Kelker 16 Sep '24

16 Sep '24

Hi, is there any chance to open the doveadm http api to handle more than one client at a time if the requests are read-only commands that have no risk of breaking something when they run simultaneously? We have a scenario of using it only for getQuota to visualize a live-status of the mailbox usage but every once in a while, there are more than one parallel requests for that that are then getting tcp connection resets. As far as I've seen it in https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/PYMMJ… spawning another doveadm http api service with another port wouldn't do the trick. If that's not possible, wouldn't be a failure code as a response a more clean approach than just refusing the connection at all? Right now, it's getting logged on the dovecot backend as "doveadm server can handle only a single client" but the requesting client gets a connection reset instead of a json-type response with a failure code. Best Kevin

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Selectively query folders for new emails
by Habakuk Tibatong 12 Sep '24

12 Sep '24

Hi folks, I have two questions: - Is it possible to exclude folders from being queried for new emails? I have many folders in my maildir, each of which has many sub-folders, with many sub-sub-folders. My Thunderbird logs in and then queries one folder after the other and this takes a very long time. However, there are only 5 folders into which I automatically sort emails with sieve, and I would like to query only these 5 folders. The other folders are folders into which I sort emails manually. It makes no sense to query them. How could I achieve this? - How can I exclude folders from being displayed in the subscribe window, i.e. that these folders exist, e.g. they are available but cannot be subscribed to, and therefore cannot be displayed in the email client? I plan to introduce a all-times "non-deletable" spam folder, which contains a copy of all spam emails that this user received and which I use to teach spamassassin, without the user being able to see, empty or delete this folder, and without him being able to infect himself with potentially infected emails.

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Dovecot v2.3.21.1 released
by Aki Tuomi 07 Sep '24

07 Sep '24

Hi all, we are releasing a CVE patch release 2.3.21.1. https://dovecot.org/releases/2.3/dovecot-2.3.21.1.tar.gz https://dovecot.org/releases/2.3/dovecot-2.3.21.1.tar.gz.sig Binary packages in https://repo.dovecot.org/ Docker images in https://hub.docker.com/r/dovecot/dovecot Kind regards, Aki Tuomi Open-Xchange oy --- - CVE-2024-23184: A large number of address headers in email resulted in excessive CPU usage. - CVE-2024-23185: Abnormally large email headers are now truncated or discarded, with a limit of 10MB on a single header and 50MB for all the headers of all the parts of an email. - oauth2: Dovecot would send client_id and client_secret as POST parameters to introspection server. These need to be optionally in Basic auth instead as required by OIDC specification. - oauth2: JWT key type check was too strict. - oauth2: JWT token audience was not validated against client_id as required by OIDC specification. - oauth2: XOAUTH2 and OAUTHBEARER mechanisms were not giving out protocol specific error message on all errors. This broke OIDC discovery. - oauth2: JWT aud validation was not performed if aud was missing from token, but was configured on Dovecot.

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~/mail/.imap
by graeme.dovecot＠vetterlein.com 05 Sep '24

05 Sep '24

the box that runs my mailsever just reported disk > 80% full , so looking to tidy up. I note: sudo du -d2 -k -x /home/graeme/mail | sort -n ... ... 66788 /home/graeme/mail/.imap/spam 198328 /home/graeme/mail/.imap 1564680 /home/graeme/mail/2023 4009336 /home/graeme/mail Now in .imap I have directories dating back to 2013 .... the corresponding mail folders have long since moved to backup. What would be the effect of deleting EVERYTHING in .imap.... will it just get recreated as needed? or do I need to take care and only remove stuff I know is no longer used?

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Can I delete duplicate messages under Maildir on the server?
by MI 05 Sep '24

05 Sep '24

After a client misconfiguration, many messages have been deleted. I restored them from backups, but now there are many duplicates. I can identify them on the server, and delete them. But do I need to also delete the dovecot.index files and/or other dovecot* files in the affected folders, or will these be automatically updated? (My Dovecot version is 2.3.13, so I guess I should not use doveadm deduplicate which would risk deleting non-duplicate messages, according to the "doveadm-deduplicate deletes non-duplicates" thread here?)

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Re: Dovecot authentication hangs when ldap_start_tls_s() fails for invalid certificate
by Aki Tuomi 04 Sep '24

04 Sep '24

> On 19/11/2020 12:55 sebastiano degan <sebastiano.degan(a)frigoveneta.it> wrote: > > > On a Debian10 I've installed postfix 3.4.14 and dovecot 2.3.4.1. > I've configured multiple passdb sources and I expect that if one fails > the other ones are tested. > This is usually the case, except when the failure is due to an invalid > certificate from the ldap server. > In that case all authentication attempts from that moment on will fail. Hi! Can you try with latest CE release from https://repo.dovecot.org/ Regards, Aki

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allow_nets check failure still performs LDAP bind authentication
by Florian Wunderlich 04 Sep '24

04 Sep '24

Postfix authentication via Dovecot. Dovecot performs the allow_nets check, which fails. It then still attempts to authenticate the user via LDAP bind, thus allowing DoS attacks where the entry in the directory will be locked after a few failed attempts. dovecot --version: 2.3.19.1 (9b53102964) Debian GNU/Linux 12 (bookworm), x86, no NFS Sep 04 07:26:05 postfix/smtpd[48225]: connect from unknown[182.176.211.10] Sep 04 07:26:17 dovecot[33863]: auth: *ldap(XXX,182.176.211.10): allow_nets check failed: IP 182.176.211.10 not in allowed networks* Sep 04 07:26:17 dovecot[33863]: auth: *ldap(XXX,182.176.211.10): Password mismatch (for LDAP bind)* Sep 04 07:26:27 postfix/smtpd[48225]: warning: unknown[182.176.211.10]: SASL LOGIN authentication failed: Connection lost to authentication server, sasl_username=(unavailable) Sep 04 07:26:27 postfix/smtpd[48225]: lost connection after AUTH from unknown[182.176.211.10] Sep 04 07:26:27 postfix/smtpd[48225]: disconnect from unknown[182.176.211.10] ehlo=2 starttls=1 auth=0/1 commands=3/4 The allow_nets extra field comes from LDAP. This works as a pass_filter query is performed first, which returns the allow_nets. /DN is looked up by sending a pass_filter LDAP request and getting the DN from the reply. This is very similar to doing a password lookup. The only difference is that userPassword attribute isn’t returned. Just as with password lookups, the pass_attrs may contain special extra fields./ https://doc.dovecot.org/2.3/configuration_manual/authentication/ldap_bind/#… After this, Dovecot should immediately fail the authentication. /If the user tries to log in from elsewhere, the authentication will fail the same way as if a wrong password was given./ https://doc.dovecot.org/2.3/configuration_manual/authentication/allow_nets/ There is no need to perform the bind authentication. According to the log (and the locked user accounts), it is still performed. Configuration is irrelevant, for completeness’s sake: auth_bind = yes pass_filter = (&(|(objectClass=simpleSecurityObject)(objectClass=posixAccount))(cn=%n)) pass_attrs = \ cn=user, \ allowNets=allow_nets

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What are all the /var/spool/smtpd/offline/1689525601.XXXXlJ85yQ
by Steve Litt 03 Sep '24

03 Sep '24

Hi all, I just filled up my whole /var with zillions of files /var/spool/smtpd/offline , dating back to 2018. What are these files and is it safe for me to delete the ones more than a week old? Thanks, SteveT Steve Litt http://444domains.com

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Inconsistency in map index with dovecot v2.3.21
by Nikolaos Pyrgiotis 02 Sep '24

02 Sep '24

Hello, We have been running dovecot version 2.3.21 since July on debian bookworm system. After upgrading we have seen in the logs similar messages to the following: 2024-08-29T19:33:27.755399+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: Warning: mdbox /path/user1/mdbox/storage: Inconsistency in map index (2213,40 != 2213,56). 2024-08-29T19:33:27.755399+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: Warning: mdbox /path/user1/mdbox/storage: Inconsistency in map index (2213,40 != 2213,56) 2024-08-29T19:33:27.838990+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: sieve: msgid=<39f9c444-0c08-4bda-bfc9-512c34584470(a)modulus.gr>: fileinto action: stored mail into mailbox 'Replies' 2024-08-29T19:33:27.840222+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: Warning: fscking index file /path/user1/mdbox/storage/dovecot.map.index 2024-08-29T19:33:27.953281+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: Warning: mdbox /path/user1/mdbox/storage: rebuilding indexes 2024-08-29T19:37:27.989792+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481249><vhzsLROj0GYQVgcAfAk26A:P1>: Error: Timeout (180s)while waiting for lock for transaction log file /path/user1/mdbox/storage/dovecot.map.index.log (WRITE lock held by pid 481240) 2024-08-29T19:37:27.995913+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481249><vhzsLROj0GYQVgcAfAk26A:P1>: Error: sieve: msgid=<39f9c444-0c08-4bda-bfc9-512c34584470(a)modulus.gr>: fileinto action: failed to store into mailbox 'Mailbox': Timeout (180s) while waiting for lock for transaction log file /path/user1/mdbox/storage/dovecot.map.index.log (WRITE lock held by pid 481240) This has happened a few times since we upgraded always by a lmtp process. It seems to be happening randomly and we have not been able to reproduce it. The mailboxes are stored in a glusterfs server, and we use the dovecot director with shared mailboxes architecture. Usually this was mitigated automatically by dovecot index rebuilding, but last time it happened on a mailbox with a lot of giga byte of mail data the following logs were produced for more than an hour: 2024-08-29T19:45:30.506694+03:00 server1 dovecot: lmtp(user1(a)modulus.gr)<481240><7TMeHNei0GYpeTkA1g8ogQ:P1>: Error: mmap_anon(/path/user/mdbox/mailboxes/Mailbox/dbox-Mails/dovecot.index.cache, 74076160) failed: Cannot allocate memory During that period segfaults starting being generated for the imap processes accessing that mailbox probably caused by timeouts from imap processes attempting to fetch emails from the affected mailbox: [3912187.557029] imap[481783]: segfault at 38 ip 00007fb03248abf8 sp 00007ffc88b264f0 error 4 in libdovecot-storage.so.0.0.0[7fb0323c7000+d8000] likely on CPU 6 (core 3, socket 0) What might be the reason that inconsistency of the map index is introduced on random users? We have seen some other users had similar issues and have mentioned them on this mailing list(dovecot Digest, Vol 249, Issue 4, dovecot Digest, Vol 250, Issue 8)? Is there any update for a mitigation or bug confirmation for dovecot version 2.3.21 that might be responsible? Thank you, Nikos Pyrgiotis

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