fetchmail_selinux (8) - Linux Manuals
fetchmail_selinux: Security Enhanced Linux Policy for the fetchmail processes
NAME
fetchmail_selinux - Security Enhanced Linux Policy for the fetchmail processesDESCRIPTION
Security-Enhanced Linux secures the fetchmail processes via flexible mandatory access control.
The fetchmail processes execute with the fetchmail_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 fetchmail_t
ENTRYPOINTS
The fetchmail_t SELinux type can be entered via the fetchmail_exec_t file type.
The default entrypoint paths for the fetchmail_t domain are the following:
PROCESS TYPES
SELinux defines process types (domains) for each process running on the systemYou can see the context of a process using the -Z option to psP Policy governs the access confined processes have to files. SELinux fetchmail policy is very flexible allowing users to setup their fetchmail processes in as secure a method as possible.
The following process types are defined for fetchmail:
fetchmail_t
Note: semanage permissive -a fetchmail_t can be used to make the process type fetchmail_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. fetchmail policy is extremely flexible and has several booleans that allow you to manipulate the policy and run fetchmail with the tightest access possible.
If you want to allow all daemons to write corefiles to /, you must turn on the daemons_dump_core boolean. Disabled by default.
setsebool -P daemons_dump_core 1
If you want to enable cluster mode for daemons, you must turn on the daemons_enable_cluster_mode boolean. Enabled by default.
setsebool -P daemons_enable_cluster_mode 1
If you want to allow all daemons to use tcp wrappers, you must turn on the daemons_use_tcp_wrapper boolean. Disabled by default.
setsebool -P daemons_use_tcp_wrapper 1
If you want to allow all daemons the ability to read/write terminals, you must turn on the daemons_use_tty boolean. Disabled by default.
setsebool -P daemons_use_tty 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 confined applications to use nscd shared memory, you must turn on the nscd_use_shm boolean. Enabled by default.
setsebool -P nscd_use_shm 1
MANAGED FILES
The SELinux process type fetchmail_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 permissions.
cluster_conf_t
cluster_var_lib_t
cluster_var_run_t
fetchmail_uidl_cache_t
fetchmail_var_run_t
root_t
sendmail_log_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 lsP Policy governs the access confined processes have to these files. SELinux fetchmail policy is very flexible allowing users to setup their fetchmail processes in as secure a method as possible.
STANDARD FILE CONTEXT
SELinux defines the file context types for the fetchmail, 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 fetchmail_var_run_t '/srv/myfetchmail_content(/.*)?'
restorecon -R -v /srv/myfetchmail_content
Note: SELinux often uses regular expressions to specify labels that match multiple files.
The following file types are defined for fetchmail:
fetchmail_etc_t
- Set files with the fetchmail_etc_t type, if you want to store fetchmail files in the /etc directories.
fetchmail_exec_t
- Set files with the fetchmail_exec_t type, if you want to transition an executable to the fetchmail_t domain.
fetchmail_home_t
- Set files with the fetchmail_home_t type, if you want to store fetchmail files in the users home directory.
- Paths:
-
/root/.fetchmailrc, /home/[^/]+/.fetchmailrc
fetchmail_initrc_exec_t
- Set files with the fetchmail_initrc_exec_t type, if you want to transition an executable to the fetchmail_initrc_t domain.
fetchmail_log_t
- Set files with the fetchmail_log_t type, if you want to treat the data as fetchmail log data, usually stored under the /var/log directory.
fetchmail_uidl_cache_t
- Set files with the fetchmail_uidl_cache_t type, if you want to store the files under the /var/cache directory.
- Paths:
-
/var/lib/fetchmail(/.*)?, /var/mail/.fetchmail-UIDL-cache
fetchmail_var_run_t
- Set files with the fetchmail_var_run_t type, if you want to store the fetchmail files under the /run or /var/run directory.
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 database. 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 policy modules.
semanage boolean can also be used to manipulate the booleans
system-config-selinux is a GUI tool available to customize SELinux policy settings.