Hello, I've been trying to set up dovecot to support passwd-file + passwd/PAM auth. I made an unusual config (passwd-file as userdb failed to work for me), which uses static as userdb: =============== passdb { driver = passwd-file args = username_format=%u scheme=CRYPT /etc/dovecot/users } userdb { driver = static default_fields = uid=vmail gid=vmail home=/var/spool/mail/%d/%n } passdb { driver = pam } userdb { driver = passwd } =============== While passwd-file+static worked well, passwd/PAM caused trouble: $ doveadm user xxx doveadm(root): Error: userdb lookup(xxx): Disconnected unexpectedly field value If passwd-file had the user, check went fine; otherwise it segfaulted. The crash has been accompanied by a syslog message: kernel: auth[9788]: segfault at 18 ip 0000000000416391 sp 00007fffd11a3d90 error 4 in auth[400000+44000] Translating address lead me to: 0000000000416390 <auth_fields_rollback>: 416390: 53 push %rbx 416391: 48 83 7f 18 00 cmpq $0x0,0x18(%rdi) I was using packages from http://packages.atrpms.net/dist/el6/dovecot/ To be precise, dovecot-2.2.10-1_14.el6.x86_64.rpm I tampered with the src.rpm, upgraded spec&sources to match 2.2.12. It didn't help, so I tries to "workaround" this. The bug has gone when in src/auth/auth-fields.c:210 I added check if the field ptr is not null. As it's a userdb query, it seems that for some reason (static?) in src/auth/auth-request.c:1058 the function auth_fields_rollback is called with null request->userdb_reply Now it works fine: $ doveadm user xxx field value uid 1000 gid 100 home /home/xxx mail maildir:~/.maildir system_groups_user xxx $ doveadm user jkonczak@ast... field value uid 103 gid 103 home /var/spool/mail/ast.../jkonczak mail maildir:~/.maildir So now virtual users get vmail uid/gid, system users get their uid/gid, home is fine etc. Below I attach the patch + full config. Regards, Jan Kończak =============================================== $ cat SOURCES/dovecot-2.2.12-auth_fields_rollback-nullptr_check.patch --- src/auth/auth-fields.c.orig 2014-05-11 16:17:49.755258666 +0200 +++ src/auth/auth-fields.c 2014-05-11 16:18:24.704946586 +0200 @@ -207,6 +207,7 @@ void auth_fields_rollback(struct auth_fields *fields) { + if (fields==NULL) return; if (array_is_created(&fields->snapshot_fields)) { array_clear(&fields->fields); array_append_array(&fields->fields, &fields->snapshot_fields); =============================================== $ dovecot --version 2.2.12 $ doveconf # passdb/userdb/auth related passdb { args = username_format=%u scheme=CRYPT /etc/dovecot/users default_fields = deny = no driver = passwd-file master = no override_fields = pass = no result_failure = continue result_internalfail = continue result_success = return-ok skip = never } passdb { args = default_fields = deny = no driver = pam master = no override_fields = pass = no result_failure = continue result_internalfail = continue result_success = return-ok skip = never } service auth { chroot = client_limit = 0 drop_priv_before_exec = no executable = auth extra_groups = group = idle_kill = 0 privileged_group = process_limit = 1 process_min_avail = 0 protocol = service_count = 0 type = unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } unix_listener auth-client { group = mode = 0600 user = $default_internal_user } unix_listener auth-login { group = mode = 0600 user = $default_internal_user } unix_listener auth-master { group = mode = 0600 user = } unix_listener auth-userdb { group = mode = 0666 user = $default_internal_user } unix_listener login/login { group = mode = 0666 user = } unix_listener token-login/tokenlogin { group = mode = 0666 user = } user = $default_internal_user vsz_limit = 18446744073709551615 B } userdb { args = default_fields = uid=vmail gid=vmail home=/var/spool/mail/%d/%n driver = static override_fields = result_failure = continue result_internalfail = continue result_success = return-ok skip = never } userdb { args = default_fields = driver = passwd override_fields = result_failure = continue result_internalfail = continue result_success = return-ok skip = never } ===============================================