platform_system_sepolicy/domain.te

# Rules for all domains.

# Allow reaping by init.
allow domain init:process sigchld;

# Read access to properties mapping.
allow domain kernel:fd use;
allow domain tmpfs:file { read getattr };

# Search /storage/emulated tmpfs mount.
allow domain tmpfs:dir r_dir_perms;

# Intra-domain accesses.
allow domain self:process {
    fork
    sigchld
    sigkill
    sigstop
    signull
    signal
    getsched
    setsched
    getsession
    getpgid
    setpgid
    getcap
    setcap
    getattr
    setrlimit
};
allow domain self:fd use;
allow domain self:dir r_dir_perms;
allow domain self:lnk_file r_file_perms;
allow domain self:{ fifo_file file } rw_file_perms;
allow domain self:unix_dgram_socket { create_socket_perms sendto };
allow domain self:unix_stream_socket { create_stream_socket_perms connectto };

# Inherit or receive open files from others.
allow domain init:fd use;
allow domain system_server:fd use;

# Connect to adbd and use a socket transferred from it.
# This is used for e.g. adb backup/restore.
allow domain adbd:unix_stream_socket connectto;
allow domain adbd:fd use;
allow domain adbd:unix_stream_socket { getattr getopt read write shutdown };

userdebug_or_eng(`
  # Same as adbd rules above, except allow su to do the same thing
  allow domain su:unix_stream_socket connectto;
  allow domain su:fd use;
  allow domain su:unix_stream_socket { getattr getopt read write shutdown };

  binder_call(domain, su)

  # Running something like "pm dump com.android.bluetooth" requires
  # fifo writes
  allow domain su:fifo_file { write getattr };

  # allow "gdbserver --attach" to work for su.
  allow domain su:process sigchld;
')

###
### Talk to debuggerd.
###
allow domain debuggerd:process sigchld;
allow domain debuggerd:unix_stream_socket connectto;

# Root fs.
allow domain rootfs:dir r_dir_perms;
allow domain rootfs:file r_file_perms;
allow domain rootfs:lnk_file r_file_perms;

# Device accesses.
allow domain device:dir search;
allow domain dev_type:lnk_file r_file_perms;
allow domain devpts:dir search;
allow domain device:file read;
allow domain socket_device:dir r_dir_perms;
allow domain owntty_device:chr_file rw_file_perms;
allow domain null_device:chr_file rw_file_perms;
allow domain zero_device:chr_file rw_file_perms;
allow domain ashmem_device:chr_file rw_file_perms;
allow domain binder_device:chr_file rw_file_perms;
allow domain ptmx_device:chr_file rw_file_perms;
allow domain log_device:dir search;
allow domain log_device:chr_file rw_file_perms;
allow domain alarm_device:chr_file r_file_perms;
allow domain urandom_device:chr_file rw_file_perms;
allow domain random_device:chr_file rw_file_perms;
allow domain properties_device:file r_file_perms;

# logd access
write_logd(domain)

# Filesystem accesses.
allow domain fs_type:filesystem getattr;
allow domain fs_type:dir getattr;

# System file accesses.
allow domain system_file:dir r_dir_perms;
allow domain system_file:file r_file_perms;
allow domain system_file:file execute;
allow domain system_file:lnk_file r_file_perms;

# Read files already opened under /data.
allow domain system_data_file:dir { search getattr };
allow domain system_data_file:file { getattr read };
allow domain system_data_file:lnk_file r_file_perms;

# Read apk files under /data/app.
allow domain apk_data_file:dir { getattr search };
allow domain apk_data_file:file r_file_perms;
allow domain apk_data_file:lnk_file r_file_perms;

# Read /data/dalvik-cache.
allow domain dalvikcache_data_file:dir { search getattr };
allow domain dalvikcache_data_file:file r_file_perms;

# Read already opened /cache files.
allow domain cache_file:dir r_dir_perms;
allow domain cache_file:file { getattr read };
allow domain cache_file:lnk_file r_file_perms;

# Read timezone related information
r_dir_file(domain, zoneinfo_data_file)

# For /acct/uid/*/tasks.
allow domain cgroup:dir { search write };
allow domain cgroup:file w_file_perms;

#Allow access to ion memory allocation device
allow domain ion_device:chr_file rw_file_perms;

# Read access to pseudo filesystems.
r_dir_file(domain, proc)
r_dir_file(domain, sysfs)
r_dir_file(domain, sysfs_devices_system_cpu)
r_dir_file(domain, inotify)
r_dir_file(domain, cgroup)
r_dir_file(domain, proc_net)

# debugfs access
allow domain debugfs:dir r_dir_perms;
allow domain debugfs:file w_file_perms;

# Get SELinux enforcing status.
allow domain selinuxfs:dir r_dir_perms;
allow domain selinuxfs:file r_file_perms;

# /data/security files
allow domain security_file:dir { search getattr };
allow domain security_file:file getattr;
allow domain security_file:lnk_file r_file_perms;

# World readable asec image contents
allow domain asec_public_file:file r_file_perms;
allow domain { asec_public_file asec_apk_file }:dir r_dir_perms;

###
### neverallow rules
###

# Do not allow any confined domain to create new unlabeled files.
neverallow { domain -unconfineddomain } unlabeled:dir_file_class_set create;

# Limit ability to ptrace or read sensitive /proc/pid files of processes
# with other UIDs to these whitelisted domains.
neverallow { domain -debuggerd -vold -dumpstate -system_server } self:capability sys_ptrace;

# Limit device node creation and raw I/O to these whitelisted domains.
neverallow { domain -kernel -init -recovery -ueventd -watchdogd -healthd -vold -uncrypt } self:capability { sys_rawio mknod };

# No process can map low memory (< CONFIG_LSM_MMAP_MIN_ADDR).
neverallow domain self:memprotect mmap_zero;

# No domain needs mac_override as it is unused by SELinux.
neverallow domain self:capability2 mac_override;

# Only recovery needs mac_admin to set contexts not defined in current policy.
neverallow { domain -recovery } self:capability2 mac_admin;

# Only init should be able to load SELinux policies.
# The first load technically occurs while still in the kernel domain,
# but this does not trigger a denial since there is no policy yet.
# Policy reload requires allowing this to the init domain.
neverallow { domain -init } kernel:security load_policy;

# Only init and the system_server can set selinux.reload_policy 1
# to trigger a policy reload.
neverallow { domain -init -system_server } security_prop:property_service set;

# Only init and system_server can write to /data/security, where runtime
# policy updates live.
# Only init can relabel /data/security (for init.rc restorecon_recursive /data).
neverallow { domain -init } security_file:{ dir file lnk_file } { relabelfrom relabelto };
# Only init and system_server can create/setattr directories with this type.
# init is for init.rc mkdir /data/security.
# system_server is for creating subdirectories under /data/security.
neverallow { domain -init -system_server } security_file:dir { create setattr };
# Only system_server can create subdirectories and files under /data/security.
neverallow { domain -system_server } security_file:dir { rename write add_name remove_name rmdir };
neverallow { domain -system_server } security_file:file { create setattr write append unlink link rename };
neverallow { domain -system_server } security_file:lnk_file { create setattr unlink rename };

# Only init prior to switching context should be able to set enforcing mode.
# init starts in kernel domain and switches to init domain via setcon in
# the init.rc, so the setenforce occurs while still in kernel. After
# switching domains, there is never any need to setenforce again by init.
neverallow domain kernel:security setenforce;
neverallow { domain -kernel } kernel:security setcheckreqprot;

# No booleans in AOSP policy, so no need to ever set them.
neverallow domain kernel:security setbool;

# Adjusting the AVC cache threshold.
# Not presently allowed to anything in policy, but possibly something
# that could be set from init.rc.
neverallow { domain -init } kernel:security setsecparam;

# Only init, ueventd and system_server should be able to access HW RNG
neverallow { domain -init -system_server -ueventd -unconfineddomain } hw_random_device:chr_file *;

# Ensure that all entrypoint executables are in exec_type.
neverallow domain { file_type -exec_type }:file entrypoint;

# Ensure that nothing in userspace can access /dev/mem or /dev/kmem
neverallow { domain -kernel -ueventd -init } kmem_device:chr_file *;
neverallow domain kmem_device:chr_file ~{ create relabelto unlink setattr };

# Only init should be able to configure kernel usermodehelpers or
# security-sensitive proc settings.
neverallow { domain -init } usermodehelper:file { append write };
neverallow { domain -init } proc_security:file { append write };

# No domain should be allowed to ptrace init.
neverallow domain init:process ptrace;

# Init can't receive binder calls. If this neverallow rule is being
# triggered, it's probably due to a service with no SELinux domain.
neverallow domain init:binder call;

# Don't allow raw read/write/open access to block_device
# Rather force a relabel to a more specific type
neverallow { domain -kernel -init -recovery -vold -uncrypt } block_device:blk_file { open read write };

# Don't allow raw read/write/open access to generic devices.
# Rather force a relabel to a more specific type.
# ueventd is exempt from this, as its managing these devices.
neverallow { domain -unconfineddomain -ueventd } device:chr_file { open read write };

# Limit what domains can mount filesystems or change their mount flags.
# sdcard_type / vfat is exempt as a larger set of domains need
# this capability, including device-specific domains.
neverallow { domain -kernel -init -recovery -vold -zygote } { fs_type -sdcard_type }:filesystem { mount remount relabelfrom relabelto };

#
# Assert that, to the extent possible, we're not loading executable content from
# outside the /system partition except for a few whitelisted domains.
#
neverallow {
    domain
    -appdomain
    -dumpstate
    -shell
    userdebug_or_eng(`-su')
    -system_server
    -zygote
} { file_type -system_file -exec_type }:file execute;

# Only the init property service should write to /data/property.
neverallow { domain -init } property_data_file:dir { create setattr relabelfrom rename write add_name remove_name rmdir };
neverallow { domain -init } property_data_file:file { create setattr relabelfrom write append unlink link rename };

# Only recovery should be doing writes to /system
neverallow { domain -recovery } { system_file exec_type }:dir_file_class_set
    { create write setattr relabelfrom relabelto append unlink link rename };

# Nothing should be writing to files in the rootfs.
neverallow domain rootfs:file { create write setattr relabelto append unlink link rename };

# Restrict context mounts to specific types marked with
# the contextmount_type attribute.
neverallow domain {fs_type -contextmount_type}:filesystem relabelto;

# Ensure that context mount types are not writable, to ensure that
# the write to /system restriction above is not bypassed via context=
# mount to another type.
neverallow { domain -recovery } contextmount_type:dir_file_class_set
    { create write setattr relabelfrom relabelto append unlink link rename };