- dovecot - dovecot.org

login failure after upgrade to dovecot 2.3.7.2
by MK 05 Sep '19

05 Sep '19

Hi List, after upgrading dovecot from version 2.2.33.2 to 2.3.7.2 I got a lot of error messages like the following if the process count of imap processes reaches nearly 1000 (~950 (there are a few pop-connections)). Sep 5 11:27:32 mailbox1 dovecot: imap-login: Internal login failure (pid=27728 id=116): user=<xxxx(a)xxxx.xx>, method=PLAIN, rip=x.x.x.x, lip=x.x.x.x, session=<qETa7cqRzpZV3IEw> Sep 5 11:27:33 mailbox1 dovecot: imap-login: Error: master(imap): net_connect_unix(imap) failed: Resource temporarily unavailable - http://wiki2.dovecot.org/SocketUnavailable (client-pid=27704, client-id=79, rip=x.x.x.x, created 511 msecs ago, received 0/4 bytes) Our setup consists of some servers with dovecot as proxy/redirector as frontend servers, redirecting the logged in users to the backend servers storing the mailboxes. OS is CentOS 6 on both server types. The backend server in question has usually ~ 2500 simultaneous imap connections. Before the update there where no problems. During the update I merged the old 2.2 config into the new 2.3 from the fresh installed binary (Repo from dovecot.org) As I found the failure above in the logfile I testet a lot, to figure out how to fix this, because for me it seemed to be some limit around 1000 connections/processes anywhere in the config. In the end I changed the default value of "default_client_limit" from ist default 1000 to 8192 and the problem was fixed for the moment. Now I'm trying to understand why this fixes the problem and what the difference is between 2.2 and 2.3. For me it seems like something changed in the architecture during the release change, but I didn't find anything. I looked into the release notes and also checked the differences beween the 2.2 and 2.3 default config values (using doveconf -d). Can anyone help? Here is the output of doveconf -n # 2.3.7.2 (3c910f64b): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.7.2 (7372921a) # OS: Linux 2.6.32-696.23.1.el6.x86_64 x86_64 CentOS release 6.10 (Final) auth_mechanisms = plain login default_client_limit = 8192 disable_plaintext_auth = no mail_location = mdbox:%h mail_plugins = quota zlib managesieve_notify_capability = mailto managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext 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 } plugin { quota = dict:User quota::file:%h/dovecot-quota quota_warning = storage=90%% quota-warning 90 %u sieve = file:~/sieve;active=~/.dovecot.sieve zlib_save = gz zlib_save_level = 6 } pop3_client_workarounds = outlook-no-nuls oe-ns-eoh protocols = imap pop3 lmtp sieve service imap-login { process_min_avail = 12 service_count = 0 } service imap { process_limit = 8192 } service lmtp { inet_listener lmtp { address = * port = 24 } } service pop3-login { process_min_avail = 12 service_count = 0 } service pop3 { process_limit = 1024 } service quota-warning { executable = script /scripts/quota.sh unix_listener quota-warning { user = vmail } user = vmail } ssl = no userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } verbose_proctitle = yes protocol lmtp { mail_plugins = quota zlib sieve } protocol imap { mail_max_userip_connections = 30 mail_plugins = quota zlib imap_quota } protocol pop3 { mail_plugins = quota zlib } greetings, Oliver

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dsync and altpath on shared storage.
by Peter Mogensen 05 Sep '19

05 Sep '19

Hi, I was wondering... If one had mdbox ALT path set to a shared storage mount (say, on NFS) and one wanted to move a mailbox to a different host... I guess it in principle wouldn't be necessary to copy all the ALT storage through dsync, when the volume could just be mounted on the new host. Is there anyway for dsync to avoid moving Gigabytes of data for could just be "moved" by moving the mount? /Peter

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Different passdb backends for different services
by lists＠mlserv.org 05 Sep '19

05 Sep '19

Hi, as Dovecot supports submission, which is the sending direction, I am interested to know, if I can configure a separate passdb backend just for submission. I habe LDAP attributes that differ sending or receiving permissions. It would be nice, if I had a second passdb backend just for submission, which has a LDAP filter for locking this service. Example for IMAP, POP3, Sieve: (&(mail=%s)(mailAllowIncoming=TRUE)) Example for Submission: (&(mail=%s)(mailAllowOutgoing=TRUE)) Use case is to lock compromised accounts that send spam. An operator can notify the account owner by placing a warning messegae into his/her mailbox. Is this possible? Thanks in advance Christian

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Global ACL in SQL or LDAP possible?
by lists＠mlserv.org 04 Sep '19

04 Sep '19

Hi, Can global ACLs for public folders be stored in SQL or LDAP instead of a dovecot-acl file? I could only find something for shared folders, but not for public folders? Thanks in advance Christian

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Server administration
by Aleksandr Mette 04 Sep '19

04 Sep '19

Dear Sirs, There is Postfix+Dovecot+Sogo installation in our company. I have attentively red Installation and Configuration Guide. However, I could not find some information. Could you give me an advise how to: 1. Add/remove e-mail address 2. Change user e-mail address password 3. Add user e-mail address into mail alias 4. Forward e-mail 5. List all users e-mails What is the best GUI interface for Dovecot administration? With kind regards, Alex

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How are imap images supposed to be stored
by d.gentner＠m4ever.de 04 Sep '19

04 Sep '19

Hello. This is a question about the imap protocol, since I am having a hard time finding these things out, so I hope you guys can help me. We are using Dovecot to receive mails and having an issue with Thunderbird. Basically, we are running into this bug with a lot of people: https://bugzilla.mozilla.org/show_bug.cgi?id=216308. <https://bugzilla.mozilla.org/show_bug.cgi?id=216308> The gist of it is, that sometimes, when there is an image linked with the imap:// protocol in the mail, then Thunderbird wants to subscribe to the folder that contains this mail, but fails. If I pull the mail off the server, it also has that link in the raw mail. However, most mails store the images as a base64 code block. I have actually seen mails getting changed over night, from imap:// links to base64 code blocks, but I can't reproduce that. All computers are supposed to have the same Thunderbird version and they do. My questions right now are: * Speaking about the general imap/mail protocol, do mails store images as base64 or imap:// links. What is the standard here? * Is there anything we can do to prevent Thunderbird from running into this bug? We are using Dovecot 2.2.36.4 * What can cause an email getting changed over night or getting synced back with the base64 blocks? It was already read, when we ran into the issue. With best regards, Domeniko Gentner

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Mailcrypt plugin private password
by info＠unkn0wn3d.com 04 Sep '19

04 Sep '19

Hello there, is there a way to make the mailcrypt plugin use the user's password or at least store it in a hashed value? I'm using a passwd file for authentication. I feel uncomfortable saving the private password in plaintext in that file. Regards

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plugin for IMAP protocol to modifie any email
by Matthew Brown 04 Sep '19

04 Sep '19

is there a plugin or anyway I can modifie any email content ? I would like to change body text, headers, attachments

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CVE-2019-11500: Critical vulnerability in Dovecot and Pigeonhole
by Aki Tuomi 04 Sep '19

04 Sep '19

Dear subscribers, we have been made aware of critical vulnerability in Dovecot and Pigeonhole. --- Open-Xchange Security Advisory 2019-08-14 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-3278 Vulnerability type: Improper input validation (CWE-20) Vulnerable version: All versions prior to 2.3.7.2 and 2.2.36.4 Vulnerable component: IMAP and ManageSieve protocol parsers (before and after login) Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.7.2, 2.2.36.4 Researcher credits: Nick Roessler and Rafi Rubin, University of Pennsylvania Vendor notification: 2019-04-13 Solution date: 2019-06-05 Public disclosure: 2019-08-28 CVE reference: CVE-2019-11500 CVSS: 8.1 (CVSS3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) Vulnerability Details: IMAP and ManageSieve protocol parsers do not properly handle NUL byte when scanning data in quoted strings, leading to out of bounds heap memory writes. Risk: This vulnerability allows for out-of-bounds writes to objects stored on the heap up to 8096 bytes in pre-login phase, and 65536 bytes post-login phase, allowing sufficiently skilled attacker to perform complicated attacks that can lead to leaking private information or remote code execution. Abuse of this bug is very difficult to observe, as it does not necessarily cause a crash. Attempts to abuse this bug are not directly evident from logs. Steps to reproduce: This bug is best observed using valgrind to see the out of bounds read with following snippet: perl -e 'print "a id (\"foo\" \"".("x"x1021)."\\A\" \"bar\" \"\000".("x"x1020)."\\A\")\n"' | nc localhost 143 Solution: Operators should update to the latest Patch Release. There is no workaround for the issue. --- Aki Tuomi Open-Xchange oy

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Dovecot and Apple's Mail.app not playing nicely?
by Coy Hile 03 Sep '19

03 Sep '19

Hi all, Is there anything cute one has to take into account when using Dovecot with users of Apple’s Mail.app? Behavior I’m seeing is that if I delete or move messages via Webmail (Roundcube, Horde, or even ActiveSync via Mail.app on my phone), they do get moved or deleted. However, if I take the same actions in the desktop mail client, when logging in to the Webmail (or phone) app, I see the messages still seeming to be in the Inbox. Is this known behavior? A peculiarity in Apple Mail? -- Coy Hile coy.hile(a)coyhile.com

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