postfix_smtp_selinux(8) SELinux Policy postfix_smtp postfix_smtp_selinux(8)NAMEpostfix_smtp_selinux - Security Enhanced Linux Policy for the post‐
fix_smtp processes
DESCRIPTION
Security-Enhanced Linux secures the postfix_smtp processes via flexible
mandatory access control.
The postfix_smtp processes execute with the postfix_smtp_t SELinux
type. You can check if you have these processes running by executing
the ps command with the -Z qualifier.
For example:
ps -eZ | grep postfix_smtp_t
ENTRYPOINTS
The postfix_smtp_t SELinux type can be entered via the post‐
fix_smtp_exec_t file type.
The default entrypoint paths for the postfix_smtp_t domain are the fol‐
lowing:
/usr/libexec/postfix/lmtp, /usr/libexec/postfix/smtp,
/usr/libexec/postfix/scache
PROCESS TYPES
SELinux defines process types (domains) for each process running on the
system
You can see the context of a process using the -Z option to ps
Policy governs the access confined processes have to files. SELinux
postfix_smtp policy is very flexible allowing users to setup their
postfix_smtp processes in as secure a method as possible.
The following process types are defined for postfix_smtp:
postfix_smtpd_t, postfix_smtp_t
Note: semanage permissive -a postfix_smtp_t can be used to make the
process type postfix_smtp_t permissive. SELinux does not deny access to
permissive process types, but the AVC (SELinux denials) messages are
still generated.
BOOLEANS
SELinux policy is customizable based on least access required. post‐
fix_smtp policy is extremely flexible and has several booleans that
allow you to manipulate the policy and run postfix_smtp with the tight‐
est access possible.
If you want to allow users to resolve user passwd entries directly from
ldap rather then using a sssd server, you must turn on the authlo‐
gin_nsswitch_use_ldap boolean. Disabled by default.
setsebool -P authlogin_nsswitch_use_ldap 1
If you want to deny any process from ptracing or debugging any other
processes, you must turn on the deny_ptrace boolean. Enabled by
default.
setsebool -P deny_ptrace 1
If you want to allow all domains to use other domains file descriptors,
you must turn on the domain_fd_use boolean. Enabled by default.
setsebool -P domain_fd_use 1
If you want to allow all domains to have the kernel load modules, you
must turn on the domain_kernel_load_modules boolean. Disabled by
default.
setsebool -P domain_kernel_load_modules 1
If you want to allow all domains to execute in fips_mode, you must turn
on the fips_mode boolean. Enabled by default.
setsebool -P fips_mode 1
If you want to enable reading of urandom for all domains, you must turn
on the global_ssp boolean. Disabled by default.
setsebool -P global_ssp 1
If you want to allow confined applications to run with kerberos, you
must turn on the kerberos_enabled boolean. Enabled by default.
setsebool -P kerberos_enabled 1
If you want to allow system to run with NIS, you must turn on the
nis_enabled boolean. Disabled by default.
setsebool -P nis_enabled 1
If you want to allow confined applications to use nscd shared memory,
you must turn on the nscd_use_shm boolean. Disabled by default.
setsebool -P nscd_use_shm 1
NSSWITCH DOMAIN
If you want to allow users to resolve user passwd entries directly from
ldap rather then using a sssd server for the postfix_smtpd_t, post‐
fix_smtp_t, you must turn on the authlogin_nsswitch_use_ldap boolean.
setsebool -P authlogin_nsswitch_use_ldap 1
If you want to allow confined applications to run with kerberos for the
postfix_smtpd_t, postfix_smtp_t, you must turn on the kerberos_enabled
boolean.
setsebool -P kerberos_enabled 1
MANAGED FILES
The SELinux process type postfix_smtp_t can manage files labeled with
the following file types. The paths listed are the default paths for
these file types. Note the processes UID still need to have DAC per‐
missions.
anon_inodefs_t
postfix_prng_t
/etc/postfix/prng_exch
postfix_smtp_tmp_t
postfix_spool_maildrop_t
/var/spool/postfix/defer(/.*)?
/var/spool/postfix/deferred(/.*)?
/var/spool/postfix/maildrop(/.*)?
postfix_spool_t
/var/spool/postfix.*
postfix_var_run_t
/var/spool/postfix/pid/.*
FILE CONTEXTS
SELinux requires files to have an extended attribute to define the file
type.
You can see the context of a file using the -Z option to ls
Policy governs the access confined processes have to these files.
SELinux postfix_smtp policy is very flexible allowing users to setup
their postfix_smtp processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the postfix_smtp, if you
wanted to store files with these types in a diffent paths, you need to
execute the semanage command to sepecify alternate labeling and then
use restorecon to put the labels on disk.
semanage fcontext -a-t postfix_smtp_exec_t '/srv/postfix_smtp/con‐
tent(/.*)?'
restorecon -R -v /srv/mypostfix_smtp_content
Note: SELinux often uses regular expressions to specify labels that
match multiple files.
The following file types are defined for postfix_smtp:
postfix_smtp_exec_t
- Set files with the postfix_smtp_exec_t type, if you want to transi‐
tion an executable to the postfix_smtp_t domain.
Paths:
/usr/libexec/postfix/lmtp, /usr/libexec/postfix/smtp,
/usr/libexec/postfix/scache
postfix_smtp_tmp_t
- Set files with the postfix_smtp_tmp_t type, if you want to store
postfix smtp temporary files in the /tmp directories.
postfix_smtpd_exec_t
- Set files with the postfix_smtpd_exec_t type, if you want to transi‐
tion an executable to the postfix_smtpd_t domain.
postfix_smtpd_tmp_t
- Set files with the postfix_smtpd_tmp_t type, if you want to store
postfix smtpd temporary files in the /tmp directories.
Note: File context can be temporarily modified with the chcon command.
If you want to permanently change the file context you need to use the
semanage fcontext command. This will modify the SELinux labeling data‐
base. You will need to use restorecon to apply the labels.
COMMANDS
semanage fcontext can also be used to manipulate default file context
mappings.
semanage permissive can also be used to manipulate whether or not a
process type is permissive.
semanage module can also be used to enable/disable/install/remove pol‐
icy modules.
semanage boolean can also be used to manipulate the booleans
system-config-selinux is a GUI tool available to customize SELinux pol‐
icy settings.
AUTHOR
This manual page was auto-generated using sepolicy manpage .
SEE ALSOselinux(8), postfix_smtp(8), semanage(8), restorecon(8), chcon(1),
sepolicy(8) , setsebool(8)postfix_smtp 13-11-20 postfix_smtp_selinux(8)
