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James Carter 8d197879f9 libsepol/cil: Allow some duplicate macro and block declarations
The commit d155b410d4 (libsepol/cil:
Check for duplicate blocks, optionals, and macros) added checks when
copying blocks, macros, and optionals so that a duplicate would cause
an exit with an error. Unfortunately, some policies exist that depend
on this behavior when using inheritance.

The behavior is as follows.

For macros only the first declared macro matters.
;
(macro m ((type ARG1))
  (allow ARG1 self (CLASS (PERM1)))
)
(block b
  (macro m ((type ARG1))
    (allow ARG1 self (CLASS (PERM2)))
  )
)
(blockinherit b)
(type t)
(call m (t))
;
For this policy segment, the macro m in block b will not be called.
Only the original macro m will be.

This behavior has been used to override macros that are going to
be inherited. Only the inherited macros that have not already been
declared in the destination namespace will be used.

Blocks seem to work fine even though there are two of them
;
(block b1
  (blockinherit b2)
  (block b
    (type t1)
    (allow t1 self (CLASS (PERM)))
  )
)
(block b2
  (block b
    (type t2)
    (allow t2 self (CLASS (PERM)))
  )
)
(blockinherit b1)
;
In this example, the blockinherit of b2 will cause there to be
two block b's in block b1. Note that if both block b's tried to
declare the same type, then that would be an error. The blockinherit
of b1 will copy both block b's.

This behavior has been used to allow the use of in-statements for
a block that is being inherited. Since the in-statements are resolved
before block inheritance, this only works if a block with the same
name as the block to be inherited is declared in the namespace.

To support the use of these two behaviors, allow duplicate blocks
and macros when they occur as the result of block inheritance. In
any other circumstances and error for a redeclaration will be given.

Since the duplicate macro is not going to be used it is just skipped.
The duplicate block will use the datum of the original block. In both
cases a warning message will be produced (it will only be seen if
"-v" is used when compiling the policy).

Signed-off-by: James Carter <jwcart2@gmail.com>
2021-08-19 11:09:15 -04:00
.circleci CircleCI: run scan-build and publish its results automatically 2019-09-26 09:45:47 -04:00
.github/workflows ci: turn on CIFuzz 2021-07-13 21:03:29 +02:00
checkpolicy checkpolicy: mark read-only parameters in policy define const 2021-07-13 21:02:10 +02:00
dbus dbus: Use GLib.MainLoop() 2021-07-28 15:01:56 -04:00
gui Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
libselinux libselinux: replace strerror by %m 2021-08-10 14:21:28 -04:00
libsemanage libsemanage: Fix USE_AFTER_FREE (CWE-672) in semanage_direct_write_langext() 2021-07-28 14:23:54 -04:00
libsepol libsepol/cil: Allow some duplicate macro and block declarations 2021-08-19 11:09:15 -04:00
mcstrans mcstrans: Improve mlstrans-test output 2021-08-10 12:25:14 -04:00
policycoreutils policycoreutils: free memory of allocated context in newrole 2021-07-19 10:42:45 -04:00
python python/sepolicy: Fix COPY_PASTE_ERROR (CWE-398) 2021-07-30 09:55:33 -04:00
restorecond Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
sandbox Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
scripts libsepol/cil: move the fuzz target and build script to the selinux repository 2021-08-17 10:33:47 -04:00
secilc secilc: fix memory leaks in secilc2conf 2021-07-19 10:42:45 -04:00
semodule-utils Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
.gitignore restorecond: Add gitignore 2016-11-16 11:20:05 -05:00
.travis.yml travis: run only selinux-testsuite 2020-11-27 15:37:31 +01:00
CleanSpec.mk
CONTRIBUTING.md Fix many misspellings 2019-09-18 22:47:35 +02:00
lgtm.yml Add configuration file for lgtm.com 2019-09-18 08:24:11 -04:00
Makefile Makefile: always build with -fno-common 2020-01-27 10:51:23 -05:00
README.md README: add OSS-Fuzz/CIFuzz badges 2021-07-13 21:03:30 +02:00
VERSION Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00

SELinux Userspace

SELinux logo Build Status OSS-Fuzz Status CIFuzz Status

Please submit all bug reports and patches to selinux@vger.kernel.org.

Subscribe by sending "subscribe selinux" in the body of an email to majordomo@vger.kernel.org.

Archive of this mailing list is available on https://lore.kernel.org/selinux/.

Installation

SELinux libraries and tools are packaged in several Linux distributions:

Building and testing

Build dependencies on Fedora:

# For C libraries and programs
dnf install \
    audit-libs-devel \
    bison \
    bzip2-devel \
    CUnit-devel \
    diffutils \
    flex \
    gcc \
    gettext \
    glib2-devel \
    make \
    libcap-devel \
    libcap-ng-devel \
    pam-devel \
    pcre-devel \
    xmlto

# For Python and Ruby bindings
dnf install \
    python3-devel \
    ruby-devel \
    swig

Build dependencies on Debian:

# For C libraries and programs
apt-get install --no-install-recommends --no-install-suggests \
    bison \
    flex \
    gawk \
    gcc \
    gettext \
    make \
    libaudit-dev \
    libbz2-dev \
    libcap-dev \
    libcap-ng-dev \
    libcunit1-dev \
    libglib2.0-dev \
    libpcre3-dev \
    pkgconf \
    python3 \
    python3-distutils \
    systemd \
    xmlto

# For Python and Ruby bindings
apt-get install --no-install-recommends --no-install-suggests \
    python3-dev \
    ruby-dev \
    swig

To build and install everything under a private directory, run:

make clean distclean

make DESTDIR=~/obj install install-rubywrap install-pywrap

On Debian PYTHON_SETUP_ARGS=--install-layout=deb needs to be set when installing the python wrappers in order to create the correct python directory structure.

To run tests with the built libraries and programs, several paths (relative to $DESTDIR) need to be added to variables $LD_LIBRARY_PATH, $PATH and $PYTHONPATH. This can be done using ./scripts/env_use_destdir:

DESTDIR=~/obj ./scripts/env_use_destdir make test

Some tests require the reference policy to be installed (for example in python/sepolgen). In order to run these ones, instructions similar to the ones in section install of ./.travis.yml can be executed.

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.

Setting CFLAGS

Setting CFLAGS during the make process will cause the omission of many defaults. While the project strives to provide a reasonable set of default flags, custom CFLAGS could break the build, or have other undesired changes on the build output. Thus, be very careful when setting CFLAGS. CFLAGS that are encouraged to be set when overriding are:

  • -fno-semantic-interposition for gcc or compilers that do not do this. clang does this by default. clang-10 and up will support passing this flag, but ignore it. Previous clang versions fail.

macOS

To install libsepol on macOS (mainly for policy analysis):

cd libsepol; make PREFIX=/usr/local install

This requires GNU coreutils:

brew install coreutils