Please submit all bug reports and patches to selinux@tycho.nsa.gov.
Subscribe via selinux-join@tycho.nsa.gov.

Build dependencies on Fedora:
yum install audit-libs-devel bison bzip2-devel dbus-devel dbus-glib-devel flex flex-devel flex-static glib2-devel libcap-devel libcap-ng-devel pam-devel pcre-devel python-devel setools-devel swig xmlto redhat-rpm-config

To build and install everything under a private directory, run:
make DESTDIR=~/obj install install-pywrap

To install as the default system libraries and binaries
(overwriting any previously installed ones - dangerous!),
on x86_64, run:
make LIBDIR=/usr/lib64 SHLIBDIR=/lib64 install install-pywrap relabel
or on x86 (32-bit), run:
make install install-pywrap relabel

This may render your system unusable if the upstream SELinux userspace
lacks library functions or other dependencies relied upon by your
distribution.  If it breaks, you get to keep both pieces.

To install libsepol on macOS (mainly for policy analysis):
cd libsepol; make PREFIX=/usr/local install

This requires GNU coreutils (brew install coreutils).


[DEV-ONLY] Compile Android SElinux binaries against SELinux master


The master branch of SELinux doesn't include native android support, and the external selinux repo from google is limited and only targets host for tools.  You can make a few edits to get some useful binaries to use on Android on master branch even though libsepol and libselinux aren't patched for android compliance, the tools are still useful.

dispol for example allows you to dump sepolicy rules for everything, for example you could recreate the supersu.te if you wanted.

checkpolicy allows you to write out a new sepolicy with edits.

getfilecon and setfilecon are very useful for getting contexts and setting contexts. I only enabled a few binaries, but there are many more you can add by following the examples in the Android.mk

by default it builds:

checkmodule
checkpolicy
chkcon
dismod
dispol
getfilecon
sefcontext_compile
setfilecon

I thought id share this here as folks often only use libsepol for sepolicy-inject and as security gets tighter it will be useful to know how to compile for target devices.  


dispol is very useful, selecting a file to output to and then choosing option 1 dumps all rules. 


also you can see specific rules, such as the filename_trans rule I implemented for Substratum's Interfacer, allowing it to auto set the contexts on files it creates in /data/system/theme to "theme_data_file". Using this 

[hide]
Select a command:
1)  display unconditional AVTAB
2)  display conditional AVTAB (entirely)
3)  display conditional AVTAB (only ENABLED rules)
4)  display conditional AVTAB (only DISABLED rules)
5)  display conditional bools
6)  display conditional expressions
7)  change a boolean value
8)  display role transitions

c)  display policy capabilities
p)  display the list of permissive types
u)  display unknown handling setting
F)  display filename_trans rules

f)  set output file
m)  display menu
q)  quit

Command ('m' for menu):  F
filename_trans rules:
 ueventd device :chr_file klog_device __kmsg__
 wpa wifi_data_file :dir wpa_socket sockets
 interfacer system_data_file :file theme_data_file theme
 system_server system_data_file :sock_file system_ndebug_socket ndebugsocket
 hostapd wifi_data_file :dir wpa_socket hostapd
 hostapd wifi_data_file :dir wpa_socket sockets

Command ('m' for menu):  p 
permissive sids:
	 recovery
	 su
	 supersu

Command ('m' for menu):  
[/hide]

similarly checkpolicy makes it easy to write out a new policy

[hide]
angler:/ $ checkpolicy /sepolicy -b -d -M -c 30 -o /sdcard/sepolicy.new                                                                            
checkpolicy:  loading policy configuration from /sepolicy
libsepol.policydb_index_others: security:  1 users, 2 roles, 801 types, 0 bools
libsepol.policydb_index_others: security: 1 sens, 1024 cats
libsepol.policydb_index_others: security:  63 classes, 13466 rules, 0 cond rules
checkpolicy:  policy configuration loaded
checkpolicy:  writing binary representation (version 30) to /sdcard/sepolicy.new
[/hide]


Theres quite a bit of trickery/makefile l33tness going on, so id encourage you to understand/look at this Sexy af Android.mk below, considering this is where most of the magic happens.

[hide]
[CODE]
LOCAL_PATH:= $(call my-dir)

libselinux_src_files := \
  libselinux/src/audit2why.c \
  libselinux/src/avc.c \
  libselinux/src/avc_internal.c \
  libselinux/src/avc_sidtab.c \
  libselinux/src/booleans.c \
  libselinux/src/callbacks.c \
  libselinux/src/canonicalize_context.c \
  libselinux/src/checkAccess.c \
  libselinux/src/check_context.c \
  libselinux/src/checkreqprot.c \
  libselinux/src/compute_av.c \
  libselinux/src/compute_create.c \
  libselinux/src/compute_member.c \
  libselinux/src/compute_relabel.c \
  libselinux/src/compute_user.c \
  libselinux/src/context.c \
  libselinux/src/deny_unknown.c \
  libselinux/src/disable.c \
  libselinux/src/enabled.c \
  libselinux/src/fgetfilecon.c \
  libselinux/src/freecon.c \
  libselinux/src/freeconary.c \
  libselinux/src/fsetfilecon.c \
  libselinux/src/get_context_list.c \
  libselinux/src/get_default_type.c \
  libselinux/src/get_initial_context.c \
  libselinux/src/getenforce.c \
  libselinux/src/getfilecon.c \
  libselinux/src/getpeercon.c \
  libselinux/src/init.c \
  libselinux/src/is_customizable_type.c \
  libselinux/src/label.c \
  libselinux/src/label_backends_android.c \
  libselinux/src/label_db.c \
  libselinux/src/label_file.c \
  libselinux/src/label_media.c \
  libselinux/src/label_support.c \
  libselinux/src/label_x.c \
  libselinux/src/lgetfilecon.c \
  libselinux/src/load_policy.c \
  libselinux/src/lsetfilecon.c \
  libselinux/src/mapping.c \
  libselinux/src/matchmediacon.c \
  libselinux/src/matchpathcon.c \
  libselinux/src/policyvers.c \
  libselinux/src/procattr.c \
  libselinux/src/query_user_context.c \
  libselinux/src/regex.c \
  libselinux/src/selinux_check_securetty_context.c \
  libselinux/src/selinux_config.c \
  libselinux/src/selinux_restorecon.c \
  libselinux/src/sestatus.c \
  libselinux/src/setenforce.c \
  libselinux/src/setexecfilecon.c \
  libselinux/src/setfilecon.c \
  libselinux/src/setrans_client.c \
  libselinux/src/seusers.c \
  libselinux/src/sha1.c \
  libselinux/src/stringrep.c

libselinux_android_srcs := \
  libselinux/src/android/android.c \
  libselinux/src/android/android_host.c \

common_src_files := \
  libsepol/src/assertion.c \
  libsepol/src/avrule_block.c \
  libsepol/src/avtab.c \
  libsepol/src/boolean_record.c \
  libsepol/src/booleans.c \
  libsepol/src/conditional.c \
  libsepol/src/constraint.c \
  libsepol/src/context.c \
  libsepol/src/context_record.c \
  libsepol/src/debug.c \
  libsepol/src/ebitmap.c \
  libsepol/src/expand.c \
  libsepol/src/genbools.c \
  libsepol/src/genusers.c \
  libsepol/src/handle.c \
  libsepol/src/hashtab.c \
  libsepol/src/hierarchy.c \
  libsepol/src/ibendport_record.c \
  libsepol/src/ibendports.c \
  libsepol/src/ibpkey_record.c \
  libsepol/src/ibpkeys.c \
  libsepol/src/iface_record.c \
  libsepol/src/interfaces.c \
  libsepol/src/kernel_to_cil.c \
  libsepol/src/kernel_to_common.c \
  libsepol/src/kernel_to_conf.c \
  libsepol/src/link.c \
  libsepol/src/mls.c \
  libsepol/src/module.c \
  libsepol/src/module_to_cil.c \
  libsepol/src/node_record.c \
  libsepol/src/nodes.c \
  libsepol/src/polcaps.c \
  libsepol/src/policydb.c \
  libsepol/src/policydb_convert.c \
  libsepol/src/policydb_public.c \
  libsepol/src/port_record.c \
  libsepol/src/ports.c \
  libsepol/src/roles.c \
  libsepol/src/services.c \
  libsepol/src/sidtab.c \
  libsepol/src/symtab.c \
  libsepol/src/user_record.c \
  libsepol/src/users.c \
  libsepol/src/util.c \
  libsepol/src/write.c


cil_src_files := \
  libsepol/cil/src/cil_binary.c \
  libsepol/cil/src/cil_build_ast.c \
  libsepol/cil/src/cil.c \
  libsepol/cil/src/cil_copy_ast.c \
  libsepol/cil/src/cil_find.c \
  libsepol/cil/src/cil_fqn.c \
  libsepol/cil/src/cil_list.c \
  libsepol/cil/src/cil_log.c \
  libsepol/cil/src/cil_mem.c \
  libsepol/cil/src/cil_parser.c \
  libsepol/cil/src/cil_policy.c \
  libsepol/cil/src/cil_post.c \
  libsepol/cil/src/cil_reset_ast.c \
  libsepol/cil/src/cil_resolve_ast.c \
  libsepol/cil/src/cil_stack.c \
  libsepol/cil/src/cil_strpool.c \
  libsepol/cil/src/cil_symtab.c \
  libsepol/cil/src/cil_tree.c \
  libsepol/cil/src/cil_verify.c

libpcre2_src_files := \
  pcre/dist2/src/pcre2_auto_possess.c \
  pcre/dist2/src/pcre2_compile.c \
  pcre/dist2/src/pcre2_config.c \
  pcre/dist2/src/pcre2_context.c \
  pcre/dist2/src/pcre2_dfa_match.c \
  pcre/dist2/src/pcre2_error.c \
  pcre/dist2/src/pcre2_find_bracket.c \
  pcre/dist2/src/pcre2_maketables.c \
  pcre/dist2/src/pcre2_match.c \
  pcre/dist2/src/pcre2_match_data.c \
  pcre/dist2/src/pcre2_jit_compile.c \
  pcre/dist2/src/pcre2_newline.c \
  pcre/dist2/src/pcre2_ord2utf.c \
  pcre/dist2/src/pcre2_pattern_info.c \
  pcre/dist2/src/pcre2_serialize.c \
  pcre/dist2/src/pcre2_string_utils.c \
  pcre/dist2/src/pcre2_study.c \
  pcre/dist2/src/pcre2_substitute.c \
  pcre/dist2/src/pcre2_substring.c \
  pcre/dist2/src/pcre2_tables.c \
  pcre/dist2/src/pcre2_ucd.c \
  pcre/dist2/src/pcre2_valid_utf.c \
  pcre/dist2/src/pcre2_xclass.c \
  pcre/dist2/src/pcre2_chartables.c


common_cflags := \
  -Wall -W -Wundef \
  -Wshadow -Wmissing-noreturn \
  -Wmissing-format-attribute \
  -std=gnu99 -O2 -fpic -fPIC \
  -pipe -fno-strict-aliasing \
  -D_GNU_SOURCE  \
  -D__BIONIC__ -DANDROID \
  -D__ANDROID__


common_ldlibs := \
  -lc

common_includes := \
  include \
  checkpolicy/ \
  libsepol/include/ \
  libsepol/src/ \
  libsepol/cil/include/ \
  libsepol/cil/src/ \
  pcre/dist2 \
  pcre/include_internal \
  pcre/include \
  libpcre/dist \
  libselinux/src \
  libsepol/include/sepol \
  libselinux/include \
  libselinux/include/selinux \
  /usr/include/python2.7 \
  /usr/include/python3.* \
  /usr/local/include

yacc_flags := -x c -std=gnu89

FIND_HOSTOS := $(shell uname -s)
HOST_NAME := $(shell echo $(FIND_HOSTOS) |sed -e s/L/l/ |sed -e s/D/d/ |sed s/W/w/ )

mkdir-android := $(shell mkdir -vp $(addprefix $(LOCAL_PATH)/libselinux/src/, android))
mkdir-include := $(shell mkdir -vp $(addprefix $(LOCAL_PATH)/include/, openssl private packagelistparser))

get-openssl := $(shell wget -qO - "https://android.googlesource.com/platform/external/boringssl/+archive/master/src/include/openssl.tar.gz" -O - | tar -xz -C include/openssl)
get-private := $(shell wget -qO - "https://android.googlesource.com/platform/system/core/+archive/master/libcutils/include/private.tar.gz" -O - | tar -xz -C include/private)
get-log := $(shell wget -qO - "https://android.googlesource.com/platform/system/core/+archive/master/liblog/include.tar.gz" -O - | tar -xz -C include)

ifeq ($(HOST_NAME),darwin)
  cmds := \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/include/selinux/android.h?format=text" | \
    base64 -D > libselinux/include/selinux/android.h) \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/src/android/android.c?format=text" | \
    base64 -D >  libselinux/src/android/android.c) \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/src/android/android_host.c?format=text" | \
    base64 -D >  libselinux/src/android/android_host.c) \
    $(shell wget -qO - "https://android.googlesource.com/platform/system/core/+/master/libpackagelistparser/include/packagelistparser/packagelistparser.h?format=text" | \
    base64 -D >  include/packagelistparser/packagelistparser.h)
else
  cmds := \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/include/selinux/android.h?format=text" | \
    base64 -d > libselinux/include/selinux/android.h) \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/src/android/android.c?format=text" | \
    base64 -d >  libselinux/src/android/android.c) \
    $(shell wget -qO - "https://android.googlesource.com/platform/external/selinux/+/master/libselinux/src/android/android_host.c?format=text" | \
    base64 -d >  libselinux/src/android/android_host.c) \
    $(shell wget -qO - "https://android.googlesource.com/platform/system/core/+/master/libpackagelistparser/include/packagelistparser/packagelistparser.h?format=text" | \
    base64 -d >  include/packagelistparser/packagelistparser.h)
endif


libselinux_prepare := $(mkdir-android) $(mkdir-include) $(get-openssl) $(get-private) $(get-log) $(cmds)
checkpolicy_prepare := \
  $(shell flex -o checkpolicy/lex.yy.c  -l checkpolicy/policy_scan.l) \
  $(shell yacc -vd checkpolicy/policy_parse.y -o checkpolicy/y.tab.c) \
  $(shell bison -vd checkpolicy/policy_parse.y --defines=checkpolicy/policy_parse.h -o checkpolicy/policy_parse.c)


##
# libpcre2.a
#
include $(CLEAR_VARS)

LOCAL_MODULE := libpcre2
LOCAL_CFLAGS += -DHAVE_CONFIG_H
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := $(libpcre2_src_files)
LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)

include $(BUILD_STATIC_LIBRARY)

##
# cil_lexer.a
#
include $(CLEAR_VARS)

LOCAL_MODULE := cil_lexer
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_CFLAGS := $(yacc_flags) $(common_cflags)
LOCAL_SRC_FILES := libsepol/cil/src/cil_lexer.l

include $(BUILD_STATIC_LIBRARY)

##
# libsepol.a
#
include $(CLEAR_VARS)

LOCAL_MODULE := libsepol
LOCAL_MODULE_TAGES := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_CFLAGS := $(common_cflags)
LOCAL_SRC_FILES := $(common_src_files)
LOCAL_MODULE_CLASS := STATIC_LIBRARIES

include $(BUILD_STATIC_LIBRARY)

##
# chkcon
#
include $(CLEAR_VARS)

LOCAL_MODULE := chkcon
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_CFLAGS := $(common_cflags)
LOCAL_SRC_FILES := libsepol/utils/chkcon.c
LOCAL_STATIC_LIBRARIES := libsepol
LOCAL_MODULE_CLASS := EXECUTABLES

include $(BUILD_EXECUTABLE)

##
# libselinux_static
#
include $(CLEAR_VARS)

LOCAL_MODULE := libselinux_static
LOCAL_MODULE_TAGS := optional
LOCAL_WHOLE_STATIC_LIBRARIES := libpcre2
LOCAL_CFLAGS := -std=gnu89 -DAUDITD_LOG_TAG=1003 -DUSE_PCRE2 $(common_cflags)
LOCAL_STATIC_LIBRARIES := libpcre2
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := $(libselinux_prepare) $(libselinux_src_files) $(libselinux_android_srcs)

include $(BUILD_STATIC_LIBRARY)

##
# sefcontext_compile
#
include $(CLEAR_VARS)

LOCAL_MODULE := sefcontext_compile
LOCAL_CFLAGS += -Wall -Werror -DUSE_PCRE2 -DNO_PERSISTENTLY_STORED_PATTERNS $(common_cflags)
LOCAL_STATIC_LIBRARIES := libselinux_static libpcre2 libsepol
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := libselinux/utils/sefcontext_compile.c
LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

##
# getfilecon
#
include $(CLEAR_VARS)

LOCAL_MODULE := getfilecon
LOCAL_CFLAGS += -Wall -Werror -DUSE_PCRE2 -DNO_PERSISTENTLY_STORED_PATTERNS $(common_cflags)
LOCAL_STATIC_LIBRARIES := libselinux_static libpcre2 libsepol
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := libselinux/utils/getfilecon.c
LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

##
# setfilecon
#
include $(CLEAR_VARS)

LOCAL_MODULE := setfilecon
LOCAL_CFLAGS += -Wall -Werror -DUSE_PCRE2 -DNO_PERSISTENTLY_STORED_PATTERNS $(common_cflags)
LOCAL_STATIC_LIBRARIES := libselinux_static libpcre2 libsepol
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := libselinux/utils/setfilecon.c
LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

##
# checkpolicy
#

include $(CLEAR_VARS)

LOCAL_SRC_FILES := \
  $(checkpolicy_prepare) \
  checkpolicy/lex.yy.c \
  checkpolicy/y.tab.c  \
  checkpolicy/checkpolicy.c \
  checkpolicy/module_compiler.c \
  checkpolicy/parse_util.c \
  checkpolicy/policy_define.c \
  checkpolicy/queue.c

LOCAL_MODULE := checkpolicy
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_CFLAGS := $(yacc_flags) $(common_cflags)
LOCAL_STATIC_LIBRARIES := libsepol
LOCAL_CFLAGS += -std=gnu99 -fpic -fPIC
LOCAL_YACCFLAGS := -v

include $(BUILD_EXECUTABLE)

##
# checkmodule
#

include $(CLEAR_VARS)

LOCAL_SRC_FILES := \
  $(checkpolicy_prepare) \
  checkpolicy/lex.yy.c \
  checkpolicy/y.tab.c  \
  checkpolicy/checkmodule.c \
  checkpolicy/module_compiler.c \
  checkpolicy/parse_util.c \
  checkpolicy/policy_define.c \
  checkpolicy/queue.c

LOCAL_MODULE := checkmodule
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_CFLAGS := $(yacc_flags) $(common_cflags)
LOCAL_STATIC_LIBRARIES := libsepol
LOCAL_CFLAGS += -std=gnu99 -fpic -fPIC
LOCAL_YACCFLAGS := -v

include $(BUILD_EXECUTABLE)

##
# dispol
#

include $(CLEAR_VARS)

LOCAL_MODULE := dispol
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := checkpolicy/test/dispol.c
LOCAL_CFLAGS := $(yacc_flags) $(common_cflags)
LOCAL_STATIC_LIBRARIES := libsepol
LOCAL_CFLAGS += -std=gnu99 -fpic -fPIC
LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)

##
# dismod
#

include $(CLEAR_VARS)

LOCAL_MODULE := dismod
LOCAL_MODULE_TAGS := optional
LOCAL_C_INCLUDES := $(common_includes)
LOCAL_SRC_FILES := checkpolicy/test/dismod.c
LOCAL_CFLAGS := $(yacc_flags) $(common_cflags)
LOCAL_STATIC_LIBRARIES :=  libsepol
LOCAL_CFLAGS += -std=gnu99 -fpic -fPIC
LOCAL_MODULE_TAGS := optional

include $(BUILD_EXECUTABLE)
[/CODE]
[/hide]

theres a submodule for libpcre2 so you'll have to use git clone --recursive, AKA

git clone --recursive https://github.com/Surge1223/selinux.git selinux-master


then building also depends on the NDK build system reading the jni/Application.mk first, before Android.mk so the NDK build command is 

[quote]$NDK/ndk-build APP_PROJECT_PATH=.   APPLICATION_BULID_SCRIPT=Application.mk[/quote]


The main purpose of me posting this here is so that in the future, if it becomes necessary to create/build tools to deal with the additional restrictions on Android, this can serve as a starting point on building.