test-glibc-security failed due to LD_AUDIT issue

[Pavel Kopylov]

I tried to run test-glibc-security.py on Ububtu18.04. There was an issue with the LD_AUDIT, environment variable. I had the following errors:

--------------- Begin of the console output ---------------
...
Running test: './test-glibc-security.py' distro: 'Ubuntu 18.04' kernel: '4.15.0-200.211 (Ubuntu 4.15.0-200.211-generic 4.15.18)' arch: 'amd64' uid: 0/0 SUDO_USER: 'testuser')
...
======================================================================
FAIL: test_70_env_okay_non_setuid (__main__.GlibcSecurityTest)
Ensure environment vars passed through to non-setuid progs
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./test-glibc-security.py", line 172, in test_70_env_okay_non_setuid
    self._run_env_cmd("./env-is-defined", env, value)
  File "./test-glibc-security.py", line 161, in _run_env_cmd
    self.assertShellExitEquals(expected, ['su', '-c', '%s %s' % (cmd, env_var), os.environ['SUDO_USER']], env=new_env)
  File "/root/qrt-test-glibc-security/testlib.py", line 1249, in assertShellExitEquals
    self.assertEqual(expected, rc, msg + result + report)
AssertionError: Got exit code -11, expected 0
Command: 'su', '-c', './env-is-defined LD_AUDIT', 'testuser'
Output:

======================================================================
FAIL: test_71_env_filtered_setuid (__main__.GlibcSecurityTest)
Ensure environment vars filtered for setuid progs
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./test-glibc-security.py", line 177, in test_71_env_filtered_setuid
    self._run_env_cmd("./env-is-defined-setuid", env, value, expected=1)
  File "./test-glibc-security.py", line 161, in _run_env_cmd
    self.assertShellExitEquals(expected, ['su', '-c', '%s %s' % (cmd, env_var), os.environ['SUDO_USER']], env=new_env)
  File "/root/qrt-test-glibc-security/testlib.py", line 1249, in assertShellExitEquals
    self.assertEqual(expected, rc, msg + result + report)
AssertionError: Got exit code -11, expected 1
Command: 'su', '-c', './env-is-defined-setuid LD_AUDIT', 'testuser'
Output:
---------------- End of the console output ----------------

However, the reason for the test to fail is the LD_AUDIT issue. For example, I ran the following command and got a SIGSEGV:

--------------- Begin of the console output ---------------
# LD_AUDIT=/lib/x86_64-linux-gnu/libmemusage.so nano
Segmentation fault
---------------- End of the console output ----------------

On the other hand, the "LD_PRELOAD=/lib/x86_64-linux-gnu/libmemusage.so nano" worked fine.

Moreover, the attempt to run the library /lib/x86_64-linux-gnu/libmemusage.so was failed with SIGSEVG, after it had been made executable of course:

--------------- Begin of the console output ---------------
# cp /lib/x86_64-linux-gnu/libmemusage.so /root/libmemusage.so
# chmod 755 /root/libmemusage.so
# /root/libmemusage.so
Segmentation fault
---------------- End of the console output ----------------

The following information about the library's version:

--------------- Begin of the console output ---------------
# dpkg -S /lib/x86_64-linux-gnu/libmemusage.so
libc6:amd64: /lib/x86_64-linux-gnu/libmemusage.so
# dpkg -s libc6
Package: libc6
Status: install ok installed
Priority: required
Section: libs
Installed-Size: 11886
Maintainer: Ubuntu Developers &lt;<email address hidden>&gt;
Architecture: amd64
Multi-Arch: same
Source: glibc
Version: 2.27-3ubuntu1.6
Replaces: libc6-amd64
Depends: libgcc1
Suggests: glibc-doc, debconf | debconf-2.0, locales
Breaks: hurd (&lt;&lt; 1:0.5.git20140203-1), libtirpc1 (&lt;&lt; 0.2.3), locales (&lt;&lt; 2.27), locales-all (&lt;&lt; 2.27), nscd (&lt;&lt; 2.27)
Conflicts: openrc (&lt;&lt; 0.27-2~)
Conffiles:
 /etc/ld.so.conf.d/x86_64-linux-gnu.conf d4e7a7b88a71b5ffd9e2644e71a0cfab
Description: GNU C Library: Shared libraries
 Contains the standard libraries that are used by nearly all programs on
 the system. This package includes shared versions of the standard C library
 and the standard math library, as well as many others.
Homepage: https://www.gnu.org/software/libc/libc.html
Original-Maintainer: GNU Libc Maintainers &lt;<email address hidden>&gt;
Original-Vcs-Browser: https://salsa.debian.org/glibc-team/glibc
Original-Vcs-Git: https://salsa.debian.org/glibc-team/glibc.git

---------------- End of the console output ----------------

I faced the aforementioned issue with libmemusage.so not only on the glibc 2.27 version but also on the glibc 2.35 version.