I’m trying to configure dovecot lmtp in multi-user mode. My error logs are filled with messages saying that an imap process cannot do a setuid to another user:
> May 21 22:28:46 imap(pid 17441 user myuser): Fatal: setuid(512(myuser) from > userdb lookup) failed with euid=501(adminuser): Operation not permitted (This > binary should probably be called with process user set to 512(myuser) instead > of 501(adminuser)) I see that others have had similar issues, but I am not able to apply any of the fixes or workarounds to solve this issue (e.g. setting libexec/dovecot/imap as setuid-root). I’ve also tried other fixes like setting the permissions to 0777 on the userdb auth for postfix smtpd. According to the code (restrict-access.c, linked below), it appears that when a user authenticates, an imap worker process is launched that has the bid of the authenticator. When another user authenticates, this last process is used, but it does not have the permissions to perform a setuid to the new user, resulting in the Fatal error that appears in the logs. Is this a bug, or a configuration issue? I’ve posted my doveconf below. Any pointers would be greatly appreciated. Steve Related: https://serverfault.com/questions/930245/dovecot-operation-not-permitted <https://serverfault.com/questions/930245/dovecot-operation-not-permitted> https://dovecot.org/list/dovecot/2012-May/135549.html <https://dovecot.org/list/dovecot/2012-May/135549.html> https://trac.macports.org/ticket/58506 <https://trac.macports.org/ticket/58506> Code at https://github.com/dovecot/core/blob/master/src/lib/restrict-access.c <https://github.com/dovecot/core/blob/master/src/lib/restrict-access.c>: https://github.com/dovecot/core/blob/863887d4272f962926ab279ac4cf37855dd2008d/src/lib/restrict-access.c#L238-L256 <https://github.com/dovecot/core/blob/863887d4272f962926ab279ac4cf37855dd2008d/src/lib/restrict-access.c#L238-L256> https://github.com/dovecot/core/blob/863887d4272f962926ab279ac4cf37855dd2008d/src/lib/restrict-access.c#L342-L346 <https://github.com/dovecot/core/blob/863887d4272f962926ab279ac4cf37855dd2008d/src/lib/restrict-access.c#L342-L346> doveconf -n: > # 2.3.0.1 (ffd8a29): /opt/local/etc/dovecot/dovecot.conf > # Pigeonhole version 0.5.0.1 (d33dca20) > # OS: Darwin 18.6.0 x86_64 apfs > auth_cache_size = 10 M > auth_gssapi_hostname = $ALL > auth_krb5_keytab = /opt/local/etc/dovecot/imap.keytab > auth_mechanisms = plain gssapi > auth_realms = host.domain.tld > auth_socket_path = /opt/local/var/run/dovecot/auth-userdb > auth_username_format = %Ln > debug_log_path = /opt/local/var/log/mail/mail-debug.log > default_internal_user = _dovecot > default_login_user = _dovenull > disable_plaintext_auth = no > first_valid_gid = 6 > first_valid_uid = 6 > imap_id_log = * > imap_id_send = "name" * "version" * > imap_idle_notify_interval = 29 mins > imap_urlauth_submit_user = submit > info_log_path = /opt/local/var/log/mail/mail-info.log > last_valid_gid = 100 > lda_mailbox_autocreate = yes > log_path = /opt/local/var/log/mail/mail-err.log > login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e %c > mail_access_groups = mail > mail_attachment_dir = /private/var/mail/tld.domain.mail/attachments > mail_attachment_fs = sis posix:mode=0666 > mail_debug = yes > mail_gid = mail > mail_home = /private/var/mail/tld.domain.mail > mail_location = mdbox:/private/var/mail/tld.domain.mail/%Ln/mdbox > mail_log_prefix = "%s(pid %p user %u): " > mail_plugins = quota zlib acl fts fts_solr fts_lucene > mail_privileged_group = mail > mail_uid = _dovecot > 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 imapsieve vnd.dovecot.imapsieve > mdbox_rotate_size = 200 M > namespace inbox { > inbox = yes > location = > mailbox Archive { > auto = subscribe > special_use = \Archive > } > mailbox Drafts { > auto = subscribe > special_use = \Drafts > } > mailbox Junk { > auto = create > special_use = \Junk > } > mailbox Notspam_train { > auto = create > special_use = \Junk > } > mailbox Sent { > auto = subscribe > special_use = \Sent > } > mailbox Spam_train { > auto = create > special_use = \Junk > } > mailbox Trash { > auto = create > special_use = \Trash > } > prefix = > separator = / > } > passdb { > driver = pam > name = pam > } > plugin { > fts = solr > fts_autoindex = yes > fts_autoindex_exclude = \Junk > fts_solr = url=http://127.0.0.1:8983/solr/dovecot/ > imapsieve_mailbox1_before = > file:/opt/local/etc/dovecot/sieve/report-spam.sieve > imapsieve_mailbox1_causes = COPY APPEND > imapsieve_mailbox1_name = Spam_train > imapsieve_mailbox2_before = > file:/opt/local/etc/dovecot/sieve/report-ham.sieve > imapsieve_mailbox2_causes = COPY APPEND > imapsieve_mailbox2_name = Notspam_train > mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename > mail_log_fields = uid box msgid from subject size flags > quota_grace = 10%% > quota_rule = *:storage=16G > quota_rule2 = Trash:storage=+256M > quota_warning = storage=100%% quota-exceeded %u > quota_warning2 = storage=80%% quota-warning %u > recipient_delimiter = + > sieve = /private/var/mail/tld.domain.mail/rules/%Ln/dovecot.sieve > sieve_after = /opt/local/etc/dovecot/sieve-after.d > sieve_before = /opt/local/etc/dovecot/sieve-before.d > sieve_dir = /private/var/mail/tld.domain.mail/rules/%Ln/%u > sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment > sieve_pipe_bin_dir = /opt/local/etc/dovecot/sieve > sieve_plugins = sieve_imapsieve sieve_extprograms > sieve_quota_max_storage = 50M > } > postmaster_address = postmas...@domain.tld > protocols = imap lmtp sieve > quota_full_tempfail = yes > sendmail_path = /opt/local/sbin/sendmail > service auth-worker { > user = root > } > service auth { > extra_groups = _keytabusers > idle_kill = 15 mins > unix_listener /opt/local/var/spool/postfix/private/auth { > group = mail > mode = 0660 > user = _postfix > } > } > service imap-login { > inet_listener imap { > address = 127.0.0.1, ::1 > port = 143 > } > inet_listener imaps { > port = 993 > ssl = yes > } > process_min_avail = 6 > service_count = 0 > vsz_limit = 2 G > } > service imap { > client_limit = 16 > process_limit = 200 > process_min_avail = 6 > service_count = 0 > } > service lmtp { > unix_listener /opt/local/var/spool/postfix/private/dovecot-lmtp { > group = mail > mode = 0660 > user = _postfix > } > } > ssl = required > ssl_ca = </etc/certificates/chain.pem > ssl_cert = </etc/certificates/cert.pem > ssl_cipher_list = > ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256 > ssl_dh = # hidden, use -P to show it > ssl_key = # hidden, use -P to show it > ssl_min_protocol = TLSv1.2 > ssl_prefer_server_ciphers = yes > userdb { > driver = passwd > name = passwd > } > verbose_proctitle = yes > protocol lda { > mail_fsync = optimized > mail_plugins = quota zlib acl fts fts_solr fts_lucene sieve > } > protocol imap { > mail_max_userip_connections = 50 > mail_plugins = quota zlib acl fts fts_solr fts_lucene imap_acl imap_quota > imap_zlib imap_sieve > } > protocol lmtp { > mail_fsync = optimized > mail_plugins = quota zlib acl fts fts_solr fts_lucene sieve > }
