Security-Enhanced Linux secures the unconfined_sendmail processes via flexible mandatory access control.
The unconfined_sendmail processes execute with the unconfined_sendmail_t SELinux type. You can check if you have these processes running by executing the ps command with the -Z qualifier.
ps -eZ | grep unconfined_sendmail_t
The unconfined_sendmail_t SELinux type can be entered via the sendmail_exec_t file type.
The default entrypoint paths for the unconfined_sendmail_t domain are the following:
/usr/sbin/sendmail(.sendmail)?, /usr/bin/esmtp, /usr/sbin/rmail, /usr/sbin/ssmtp, /usr/lib/sendmail, /usr/bin/esmtp-wrapper, /var/qmail/bin/sendmail, /usr/sbin/sendmail.postfix
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 psbP
Policy governs the access confined processes have to files. SELinux unconfined_sendmail policy is very flexible allowing users to setup their unconfined_sendmail processes in as secure a method as possible.
The following process types are defined for unconfined_sendmail:
Note: semanage permissive -a unconfined_sendmail_t can be used to make the process type unconfined_sendmail_t permissive. SELinux does not deny access to permissive process types, but the AVC (SELinux denials) messages are still generated.
SELinux policy is customizable based on least access required. unconfined_sendmail policy is extremely flexible and has several booleans that allow you to manipulate the policy and run unconfined_sendmail with the tightest access possible.
If you want to deny user domains applications to map a memory region as both executable and writable, this is dangerous and the executable should be reported in bugzilla, you must turn on the deny_execmem boolean. Enabled by default.
setsebool -P deny_execmem 1
If you want to control the ability to mmap a low area of the address space, as configured by /proc/sys/vm/mmap_min_addr, you must turn on the mmap_low_allowed boolean. Disabled by default.
setsebool -P mmap_low_allowed 1
If you want to disable kernel module loading, you must turn on the secure_mode_insmod boolean. Enabled by default.
setsebool -P secure_mode_insmod 1
If you want to allow unconfined executables to make their heap memory executable. Doing this is a really bad idea. Probably indicates a badly coded executable, but could indicate an attack. This executable should be reported in bugzilla, you must turn on the selinuxuser_execheap boolean. Disabled by default.
setsebool -P selinuxuser_execheap 1
If you want to allow unconfined executables to make their stack executable. This should never, ever be necessary. Probably indicates a badly coded executable, but could indicate an attack. This executable should be reported in bugzilla, you must turn on the selinuxuser_execstack boolean. Enabled by default.
setsebool -P selinuxuser_execstack 1
The SELinux process type unconfined_sendmail_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.
all files on the system
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.
This manual page was auto-generated using sepolicy manpage .
selinux(8), unconfined_sendmail(8), semanage(8), restorecon(8), chcon(1), sepolicy(8), setsebool(8)