ityuki / run_qmail_on_centos8_and_selinux

How to run qmail on SELinux (CentOS 8 as an example)

How to run qmail on SELinux

• This setting is a sample.
• There is no guarantee.
• Information is provided by AS IS.
• I'm not good at English. sorry.
• If you find a mistake, please write it in the issue

Target Linux distribution

• CentOS 8

precondition

• CentOS 8 is running.

• qmail installed. (./setup setup check is finished)

• The setting of control/ files completed.

  • Probably the minimum required files are:
    • /var/qmail/control/me
    • /var/qmail/control/defaultdomain
    • /var/qmail/control/rcpthosts

• SELinux tools installed. if not installed, run next yum command.

yum install setools-console selinux-policy-devel

environment

• qmail install path: /var/qmail

---

Set fcontext /var/qmail

restorecon -RFv /var/qmail

qmail-start on systemd

• /etc/systemd/system/qmail-start.service

[Unit]
Description=qmail server daemon
After=syslog.target network.target auditd.service

[Service]
Environment="PATH=/var/qmail/bin:/bin:/usr/bin:/usr/local/bin"
ExecStart=/var/qmail/bin/qmail-start ./Maildir/ splogger qmail
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process
Restart=always
SyslogIdentifier=qmail-start
SyslogFacility=daemon
SyslogLevel=info
SELinuxContext=system_u:system_r:qmail_start_t:s0

[Install]
WantedBy=multi-user.target

Allows qmail-start on SELinux

• make qmail_splogger_t.te file

module qmail_splogger_t 1.0;
require {
        type devlog_t;
        type qmail_splogger_t;
        type init_var_run_t;
        type syslogd_var_run_t;
        type kernel_t;
        class lnk_file read;
        class sock_file write;
        class unix_dgram_socket sendto;
        class dir search;
}

allow qmail_splogger_t devlog_t:lnk_file read;
allow qmail_splogger_t devlog_t:sock_file write;
allow qmail_splogger_t init_var_run_t:dir search;
allow qmail_splogger_t kernel_t:unix_dgram_socket sendto;
allow qmail_splogger_t syslogd_var_run_t:dir search;

• install module

checkmodule -M -m -o qmail_splogger_t.mod qmail_splogger_t.te
semodule_package -o qmail_splogger_t.pp -m qmail_splogger_t.mod
semodule -i qmail_splogger_t.pp

• make qmail_clean_t.te file

module qmail_clean_t 1.0;
require {
        type qmail_clean_t;
        type qmail_spool_t;
        class dir { unlink read rw_dir_perms };
        class file { unlink read getattr };
}
allow qmail_clean_t qmail_spool_t:dir { unlink read rw_dir_perms };
allow qmail_clean_t qmail_spool_t:file { unlink read getattr };

• install module

checkmodule -M -m -o qmail_clean_t.mod qmail_clean_t.te
semodule_package -o qmail_clean_t.pp -m qmail_clean_t.mod
semodule -i qmail_clean_t.pp

• make qmail_lspawn_t.te file

module qmail_lspawn_t 1.0;

require {
        type qmail_lspawn_t;
        type var_t;
        class file { open read };
}
allow qmail_lspawn_t var_t:file { open read };

• install module

checkmodule -M -m -o qmail_lspawn_t.mod qmail_lspawn_t.te
semodule_package -o qmail_lspawn_t.pp -m qmail_lspawn_t.mod
semodule -i qmail_lspawn_t.pp

• make qmail_queue_t.te file

module qmail_queue_t 1.0;

require {
        type qmail_queue_t;
        type qmail_start_t;
        class fifo_file { read write };
}
allow qmail_queue_t qmail_start_t:fifo_file { read write };

• install module

checkmodule -M -m -o qmail_queue_t.mod qmail_queue_t.te
semodule_package -o qmail_queue_t.pp -m qmail_queue_t.mod
semodule -i qmail_queue_t.pp

• run qmail-start and check status

systemctl start qmail-start
systemctl status qmail-start

• If status have not error, to enable service

systemctl enable qmail-start

qmail-smtpd on systemd

• make /etc/systemd/system/qmail-smtpd.socket file

[Unit]
Description=Stream socket for qmail-smtpd server

[Socket]
ListenStream=0.0.0.0:25
Accept=yes

[Install]
WantedBy=sockets.target

• make /etc/systemd/system/[email protected] file

[Unit]
Description=qmail-smtpd server
Requires=qmail-smtpd.socket
After=qmail-smtpd.socket

[Service]
ExecStart=/var/qmail/bin/tcp-env /var/qmail/bin/qmail-smtpd
StandardInput=socket
StandardOutput=socket
User=qmaild
Group=nofiles
SELinuxContext=system_u:system_r:inetd_t:s0

[Install]
WantedBy=qmail-smtpd.socket

Allows qmail-smtpd on SELinux

• make qmail_tcp_env_exec_t.te file

module qmail_tcp_env_exec_t 1.0;

require {
        type qmail_tcp_env_exec_t;
        type qmail_tcp_env_t;
        type inetd_t;
        type init_t;
        type node_t;
        class file entrypoint;
        class process transition;
        class tcp_socket node_bind;
}
allow init_t inetd_t:process transition;
allow inetd_t qmail_tcp_env_exec_t:file entrypoint;
allow qmail_tcp_env_t node_t:tcp_socket node_bind;

• install module

checkmodule -M -m -o qmail_tcp_env_exec_t.mod qmail_tcp_env_exec_t.te
semodule_package -o qmail_tcp_env_exec_t.pp -m qmail_tcp_env_exec_t.mod
semodule -i qmail_tcp_env_exec_t.pp

• make socket_qmail_tcp_env_t.te file

module socket_qmail_tcp_env_t 1.0;

require {
        type smtp_port_t;
        type init_t;
        type qmail_tcp_env_t;
        class tcp_socket { accept bind create getattr ioctl listen name_bind setopt };
}
allow init_t qmail_tcp_env_t:tcp_socket { accept bind create getattr ioctl listen setopt };
allow qmail_tcp_env_t smtp_port_t:tcp_socket name_bind;

• install module

checkmodule -M -m -o socket_qmail_tcp_env_t.mod socket_qmail_tcp_env_t.te
semodule_package -o socket_qmail_tcp_env_t.pp -m socket_qmail_tcp_env_t.mod
semodule -i socket_qmail_tcp_env_t.pp

• run qmail-smtpd.socket and check status

systemctl start qmail-smtpd.socket
systemctl status qmail-smtpd.socket

• If status have not error, to enable service

systemctl enable qmail-smtpd.socket

qmail-start and qmail-smtpd is runnning!

• check error on /var/log/audit/audit.log
• probably you can send and receive by SMTP
• qmail-pop3d? I don't use it so I don't know.
  • Let's use Dovecot!

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Thank you.

copyright (c) 2020 Ituki Kirihara/NI All rights reserved.