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This is the upstream repository for the Security Enhanced Linux (SELinux) userland libraries and tools. The software provided by this project complements the SELinux features integrated into the Linux kernel and is used by Linux distributions. All bugs an
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1089665e31
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Jeff Vander Stoep 1089665e31 Add attribute expansion options 
This commit adds attribute expansion statements to the policy
language allowing compiler defaults to be overridden.

Always expands an attribute example:
expandattribute { foo } true;
CIL example:
(expandtypeattribute (foo) true)

Never expand an attribute example:
expandattribute { bar } false;
CIL example:
(expandtypeattribute (bar) false)

Adding the annotations directly to policy was chosen over other
methods as it is consistent with how targeted runtime optimizations
are specified in other languages. For example, in C the "inline"
command.

Motivation

expandattribute true:
Android has been moving away from a monolithic policy binary to
a two part split policy representing the Android platform and the
underlying vendor-provided hardware interface. The goal is a stable
API allowing these two parts to be updated independently of each
other. Attributes provide an important mechanism for compatibility.
For example, when the vendor provides a HAL for the platform,
permissions needed by clients of the HAL can be granted to an
attribute. Clients need only be assigned the attribute and do not
need to be aware of the underlying types and permissions being
granted.

Inheriting permissions via attribute creates a convenient mechanism
for independence between vendor and platform policy, but results
in the creation of many attributes, and the potential for performance
issues when processes are clients of many HALs. [1] Annotating these
attributes for expansion at compile time allows us to retain the
compatibility benefits of using attributes without the performance
costs. [2]

expandattribute false:
Commit 0be23c3f15 added the capability to aggresively remove unused
attributes. This is generally useful as too many attributes assigned
to a type results in lengthy policy look up times when there is a
cache miss. However, removing attributes can also result in loss of
information used in external tests. On Android, we're considering
stripping neverallow rules from on-device policy. This is consistent
with the kernel policy binary which also did not contain neverallows.
Removing neverallow rules results in a 5-10% decrease in on-device
policy build and load and a policy size decrease of ~250k. Neverallow
rules are still asserted at build time and during device
certification (CTS). If neverallow rules are absent when secilc is
run, some attributes are being stripped from policy and neverallow
tests in CTS may be violated. [3] This change retains the aggressive
attribute stripping behavior but adds an override mechanism to
preserve attributes marked as necessary.

[1] https://github.com/SELinuxProject/cil/issues/9
[2] Annotating all HAL client attributes for expansion resulted in
    system_server's dropping from 19 attributes to 8. Because these
    attributes were not widely applied to other types, the final
    policy size change was negligible.
[3] data_file_type and service_manager_type are stripped from AOSP
    policy when using secilc's -G option. This impacts 11 neverallow
    tests in CTS.

Test: Build and boot Marlin with all hal_*_client attributes marked
    for expansion. Verify (using seinfo and sesearch) that permissions
    are correctly expanded from attributes to types.
Test: Mark types being stripped by secilc with "preserve" and verify
    that they are retained in policy and applied to the same types.

Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
2017-05-09 12:09:46 -04:00
checkpolicy Add attribute expansion options 2017-05-09 12:09:46 -04:00
dbus dbus: Use text streams in selinux_server.py 2017-05-05 11:52:19 -04:00
gui sepolicy: Adapt to new the semodule list output 2017-05-05 11:52:19 -04:00
libselinux libselinux: Fix CFLAGS definition 2017-05-09 10:47:39 -04:00
libsemanage Makefiles: drop -L/-I to system paths 2017-04-25 08:27:05 -04:00
libsepol Add attribute expansion options 2017-05-09 12:09:46 -04:00
mcstrans Makefiles: drop -L/-I to system paths 2017-04-25 08:27:05 -04:00
policycoreutils sestatus: show checkreqprot status 2017-05-08 12:44:12 -04:00
python sepolicy/gui: Update text strings to use better gettext templates 2017-05-05 11:52:19 -04:00
restorecond restorecond: get pcre cflags/libs from pkg-config 2017-04-25 08:27:44 -04:00
sandbox Makefiles: drop -L/-I to system paths 2017-04-25 08:27:05 -04:00
scripts Fix release script 2016-11-16 11:19:51 -05:00
secilc Makefiles: drop -L/-I to system paths 2017-04-25 08:27:05 -04:00
semodule-utils Makefiles: drop -L/-I to system paths 2017-04-25 08:27:05 -04:00
.gitignore restorecond: Add gitignore 2016-11-16 11:20:05 -05:00
.travis.yml libsemanage/tests: include libsepol headers from $DESTDIR 2017-03-01 10:42:34 -05:00
CleanSpec.mk Add empty top level Android.mk / CleanSpec.mk files 2015-04-16 07:54:09 -04:00
Makefile Add includes for DESTDIR only in root Makefile 2017-04-25 08:31:10 -04:00
README libsepol compilation fixes for macOS. 2017-01-20 13:19:57 -05:00

README 

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 DESTDIR=/usr/local PREFIX=/usr/local install

This requires GNU coreutils (brew install coreutils).