bug report: imap-login not killed

Sacha sacha at aquilenet.fr
Sat Mar 4 15:10:17 UTC 2023


Hi,

We have growing imap-login processes until we reach the max processes.

This occurs when a particular user have a login error due to our LDAP 
misconfiguration:

---
Mar  4 14:59:33 hera dovecot[2226963]: auth: Error: 
plain(john.doe,XX.XX.XX.XX,<13C0eBP2354lqXpO>): user not found from any 
userdbs
Mar  4 14:59:33 hera dovecot[2226963]: imap: Error: auth-master: login: 
request [1001652225]: Login auth request failed: Authenticated user not 
found from
userdb, auth lookup id=1001652225 (auth connected 2 msecs ago, request 
took 1 msecs, client-pid=2235348 client-id=1)
Mar  4 14:59:33 hera dovecot[2226963]: imap-login: Internal login 
failure (pid=2235348 id=1): user=<ohn.doe>, method=PLAIN, 
rip=XX.XX.XX.XX, lip=18
5.233.100.1, mpid=2235359, TLS, session=<13C0eBP2354lqXpO>
---

The origin of is issue is when passdb finds the user and userdb not. The 
result is imap-login processes with no timeout growing until we reach 
the max processes.

  * OS version

Debian stable - Bullseye

  * Dovecot version

dpkg -l |grep dovecot
ii  dovecot-antispam                    2.0+20171229-1+b7 
                     amd64        Dovecot plugins for training spam filters
ii  dovecot-common                      1:2.1.7-7+deb7u1 
                      all          Transitional package for dovecot
ii  dovecot-core                        1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - core files
ii  dovecot-core-dbgsym                 1:2.3.13+dfsg1-2+deb11u1 
              amd64        debug symbols for dovecot-core
ii  dovecot-imapd                       1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - IMAP daemon
ii  dovecot-imapd-dbgsym                1:2.3.13+dfsg1-2+deb11u1 
              amd64        debug symbols for dovecot-imapd
ii  dovecot-ldap                        1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - LDAP support
ii  dovecot-managesieved                1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - ManageSieve server
ii  dovecot-mysql                       1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - MySQL support
ii  dovecot-pop3d                       1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - POP3 daemon
ii  dovecot-sieve                       1:2.3.13+dfsg1-2+deb11u1 
              amd64        secure POP3/IMAP server - Sieve filters support

  * doveconf -n

---
# 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.13 (cdd19fe3)
doveconf: Warning: service auth { client_limit=1000 } is lower than 
required under max. load (4096)
doveconf: Warning: service anvil { client_limit=1000 } is lower than 
required under max. load (4099)
# OS: Linux 5.10.0-21-cloud-amd64 x86_64 Debian 11.6 ext4
# Hostname: XXX
auth_mechanisms = plain login
default_process_limit = 1024
first_valid_gid = 8
first_valid_uid = 109
last_valid_gid = 8
last_valid_uid = 109
login_greeting = XXX listening.
mail_access_groups = mail
mail_gid = 8
mail_location = maildir:/srv/vmail/%d/%n
mail_privileged_group = mail
mail_uid = 109
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy i
nclude variables body enotify environment mailbox date index ihave 
duplicate mime foreverypart extracttext imapflags notify imapsieve 
vnd.dovecot.imapsieve
vnd.dovecot.filter
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-ldap.conf
  driver = ldap
}
passdb {
  args = /etc/dovecot/dovecot-ldap-girondix.conf
  driver = ldap
}
passdb {
  args = /etc/dovecot/dovecot-oauth2.conf.ext
  driver = oauth2
  mechanisms = xoauth2 oauthbearer
}
plugin {
  quota_rule = *:storage=100M
  quota_rule2 = Trash:storage=10%%
  recipient_delimiter = +
  sieve = /srv/vmail/%d/%n/dovecot.sieve
  sieve_default = /var/lib/dovecot/sieve/default.sieve
  sieve_dir = /srv/vmail/%d/%n/sieve
  sieve_extensions = +notify +imapflags +vnd.dovecot.filter
  sieve_filter_bin_dir = /usr/lib/dovecot/sieve-filter
  sieve_global_extensions = +vnd.dovecot.pipe
  sieve_max_script_size = 1M
  sieve_pipe_bin_dir = /etc/dovecot/sieve
  sieve_pipe_socket_dir = sieve-pipe
  sieve_plugins = sieve_imapsieve sieve_extprograms
  sieve_redirect_envelope_from = orig_recipient
}
protocols = imap pop3 sieve
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = mail
    mode = 0600
    user = postfix
  }
  unix_listener auth-master {
    group = mail
    mode = 0660
    user = vmail
  }
  unix_listener auth-userdb {
    group = mail
    mode = 0600
    user = vmail
  }
}
service imap-login {
  inet_listener imap {
    port = 0
  }
}
service imap {
  vsz_limit = 1 G
}
service lmtp {
  executable = lmtp -L
  process_min_avail = 2
}
service pop3-login {
  inet_listener pop3 {
    port = 0
  }
}
ssl_cert = </srv/letsencrypt/pem/mail.aquilenet.fr.pem
ssl_client_ca_dir = /etc/ssl/certs
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
userdb {
  args = /etc/dovecot/dovecot-ldap.conf
  driver = ldap
}
userdb {
  args = /etc/dovecot/dovecot-ldap-girondix.conf
  driver = ldap
}
protocol lmtp {
  auth_username_format = %n
  info_log_path = /var/log/dovecot-lmtp.log
  mail_plugins = " sieve"
}
protocol lda {
  mail_plugins = " mailbox_alias sieve"
}
protocol imap {
  imap_client_workarounds = delay-newmail tb-extra-mailbox-sep
  imap_idle_notify_interval = 30 secs
  mail_max_userip_connections = 50
  mail_plugins = quota  mailbox_alias imap_quota
}
protocol pop3 {
  mail_plugins = quota mailbox_alias acl
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
}
---
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