Go to file
Nicolas Iooss af29a23553
libsepol/cil: do not allow \0 in quoted strings
Using the '\0' character in strings in a CIL policy is not expected to
happen, and makes the flex tokenizer very slow. For example when
generating a file with:

    python -c 'print("\"" + "\0"*100000 + "\"")' > policy.cil

secilc fails after 26 seconds, on my desktop computer. Increasing the
numbers of \0 makes this time increase significantly. But replacing \0
with another character makes secilc fail in only few milliseconds.

Fix this "possible denial of service" issue by forbidding \0 in strings
in CIL policies.

Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=36016

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
2021-07-13 21:05:03 +02:00
.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 Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
gui Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
libselinux libselinux: silence -Wextra-semi-stmt warning 2021-07-06 11:08:11 -04:00
libsemanage libsemanage: silence -Wextra-semi-stmt warning 2021-07-06 11:08:11 -04:00
libsepol libsepol/cil: do not allow \0 in quoted strings 2021-07-13 21:05:03 +02:00
mcstrans mcstrans: silence -Wextra-semi-stmt warning 2021-07-06 11:08:11 -04:00
policycoreutils policycoreutils: silence -Wextra-semi-stmt warning 2021-07-06 11:08:11 -04:00
python Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
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 scripts/ci: use F34 image instead of F33 2021-05-18 10:05:03 +02:00
secilc libsepol/cil: Add support for using qualified names to secil2conf 2021-07-03 16:00:30 +02:00
semodule-utils Update VERSIONs to 3.2 for release. 2021-03-04 16:42:59 +01:00
.gitignore
.travis.yml travis: run only selinux-testsuite 2020-11-27 15:37:31 +01:00
CONTRIBUTING.md Fix many misspellings 2019-09-18 22:47:35 +02:00
CleanSpec.mk
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
lgtm.yml Add configuration file for lgtm.com 2019-09-18 08:24:11 -04:00

README.md

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