tcpd_selinux(8) SELinux Policy tcpd tcpd_selinux(8)NAMEtcpd_selinux - Security Enhanced Linux Policy for the tcpd processes
DESCRIPTION
Security-Enhanced Linux secures the tcpd processes via flexible manda‐
tory access control.
The tcpd processes execute with the tcpd_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 tcpd_t
ENTRYPOINTS
The tcpd_t SELinux type can be entered via the tcpd_exec_t file type.
The default entrypoint paths for the tcpd_t domain are the following:
/usr/sbin/tcpd
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
tcpd policy is very flexible allowing users to setup their tcpd pro‐
cesses in as secure a method as possible.
The following process types are defined for tcpd:
tcpd_t
Note: semanage permissive -a tcpd_t can be used to make the process
type tcpd_t permissive. SELinux does not deny access to permissive
process types, but the AVC (SELinux denials) messages are still gener‐
ated.
BOOLEANS
SELinux policy is customizable based on least access required. tcpd
policy is extremely flexible and has several booleans that allow you to
manipulate the policy and run tcpd with the tightest access possible.
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 system to run with NIS, you must turn on the
nis_enabled boolean. Disabled by default.
setsebool -P nis_enabled 1
MANAGED FILES
The SELinux process type tcpd_t can manage files labeled with the fol‐
lowing file types. The paths listed are the default paths for these
file types. Note the processes UID still need to have DAC permissions.
tcpd_tmp_t
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 tcpd policy is very flexible allowing users to setup their tcpd
processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the tcpd, 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 tcpd_exec_t '/srv/tcpd/content(/.*)?'
restorecon -R -v /srv/mytcpd_content
Note: SELinux often uses regular expressions to specify labels that
match multiple files.
The following file types are defined for tcpd:
tcpd_exec_t
- Set files with the tcpd_exec_t type, if you want to transition an
executable to the tcpd_t domain.
tcpd_tmp_t
- Set files with the tcpd_tmp_t type, if you want to store tcpd tempo‐
rary 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), tcpd(8), semanage(8), restorecon(8), chcon(1), sepolicy(8)
, setsebool(8)tcpd 13-11-20 tcpd_selinux(8)