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Nicolas Iooss ded385d377 libselinux: initialize temp value in SWIG wrapper to prevent freeing garbage
Currently this Python program triggers a segmentation fault in
libselinux SWIG wrapper:

    import selinux
    selinux.get_ordered_context_list()

gdb shows that the segmentation fault occurs when freeing some memory:

    Reading symbols from python...(no debugging symbols found)...done.
    Starting program: /usr/bin/python -c import\
    selinux\;selinux.get_ordered_context_list\(\)
    [Thread debugging using libthread_db enabled]
    Using host libthread_db library "/usr/lib/libthread_db.so.1".

    Program received signal SIGSEGV, Segmentation fault.
    0x00007ffff789a304 in free () from /usr/lib/libc.so.6
    (gdb) bt
    #0  0x00007ffff789a304 in free () from /usr/lib/libc.so.6
    #1  0x00007ffff6011499 in freeconary (con=0x7ffff6ac5d00) at
    freeconary.c:14
    #2  0x00007ffff6296899 in _wrap_get_ordered_context_list
    (self=<optimized out>, args=<optimized out>) at
    selinuxswig_wrap.c:6185
    #3  0x00007ffff741891f in _PyCFunction_FastCallDict () from
    /usr/lib/libpython3.6m.so.1.0
    ...

SWIG generated the following code for _wrap_get_ordered_context_list():

    char ***arg3 = (char ***) 0 ;
    char **temp3 ;
    arg3 = &temp3;
    if (!PyArg_ParseTuple(args, "OO:get_ordered_context_list",&obj0,&obj1))
        SWIG_fail;
    /* ... */
  fail:
    if (*arg3) freeconary(*arg3);

If PyArg_ParseTuple fails, freeconary() is called on the value of
"temp3", which has not been initialized. Fix this by initializing temp
to NULL in the SWIG template.

A similar issue exists with security_get_boolean_names(). Fix it too.

This issue has been found using clang's static analyzer, on a system
which uses SWIG 3.0.12.

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
2017-03-01 10:42:45 -05:00
checkpolicy checkpolicy: Make print_error_msg() static 2017-02-06 11:01:32 -05:00
dbus Add stub make test targets to new subdirs 2016-11-16 11:20:05 -05:00
gui Add stub make test targets to new subdirs 2016-11-16 11:20:05 -05:00
libselinux libselinux: initialize temp value in SWIG wrapper to prevent freeing garbage 2017-03-01 10:42:45 -05:00
libsemanage libsemanage/tests: include libsepol headers from $DESTDIR 2017-03-01 10:42:34 -05:00
libsepol libsepol/cil: do not dereference args before checking it was not null 2017-03-01 10:42:23 -05:00
mcstrans mcstrans: do not dereference color_str if it is NULL 2017-03-01 10:42:39 -05:00
policycoreutils policycoreutils/semodule: fix -Wwrite-strings warnings 2017-02-06 11:06:42 -05:00
python sepolgen: strip non-printable characters when parsing audit messages 2017-02-21 13:43:09 -05:00
restorecond policycoreutils/restorecond: Decrease loglevel of termination message 2017-01-06 14:06:40 -05:00
sandbox sandbox: make test not fail on systems without SELinux 2016-11-17 16:44:57 -05:00
scripts Fix release script 2016-11-16 11:19:51 -05:00
secilc secilc: Add secil2conf which creates a policy.conf from CIL policy 2016-11-30 10:18:19 -05:00
semodule-utils semodule_package: do not leak memory when using -u or -s 2017-03-01 10:42:16 -05:00
.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 Build mcstrans. 2016-11-16 11:19:50 -05:00
README libsepol compilation fixes for macOS. 2017-01-20 13:19:57 -05:00

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).