Antony Antony - 3 months ago 58
Linux Question

Build OpenVPN with specific OpenSSL version

Similar questions have been asked before, but the answers no longer seem to apply as the flags have changed for the configure script. I am trying to compile OpenVPN from the git source on Ubuntu 14.04.5 on both x86 and x64. I have OpenSSL 1.0.1t built and installed to /usr/local/ssl. I've tried various combinations of the configure options and the compiler seems to recognize since

./configure OPENSSL_LIBS="-L/usr/local/ssl/ -lssl -lcrypto" OPENSSL_CFLAGS="-I/usr/local/ssl/include/"


finishes with no errors, but
./configure OPENSSL_LIBS="-L/usr/local/ssl/" OPENSSL_CFLAGS="-I/usr/local/ssl/include/"
results in
configure: error: openssl check failed
. Once you do make and make install, it still reports the system version of OpenSSL:

root@anonymous:/usr/local/src/openvpn# openvpn --version
OpenVPN 2.3_git [git:master/d1bd37fd508ee046] x86_64-unknown-linux-gnu [SSL (OpenSSL)]
[LZO] [LZ4] [EPOLL] [MH] [IPv6] built on Aug 16 2016
library versions: OpenSSL 1.0.1f 6 Jan 2014, LZO 2.06
Originally developed by James Yonan
Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
Compile time defines: enable_async_push=no enable_comp_stub=no enable_crypto=yes
enable_crypto_ofb_cfb=yes enable_debug=yes enable_def_auth=yes enable_dlopen=unknown
enable_dlopen_self=unknown enable_dlopen_self_static=unknown enable_fast_install=yes
enable_fragment=yes enable_iproute2=no enable_libtool_lock=yes enable_lz4=yes
enable_lzo=yes enable_management=yes enable_multi=yes enable_multihome=yes enable_pam_dlopen=no
enable_pedantic=no enable_pf=yes enable_pkcs11=no enable_plugin_auth_pam=yes
enable_plugin_down_root=yes enable_plugins=yes enable_port_share=yes enable_selinux=no
enable_server=yes enable_shared=yes enable_shared_with_static_runtimes=no enable_small=no
enable_static=yes enable_strict=no enable_strict_options=no enable_systemd=no
enable_werror=no enable_win32_dll=yes enable_x509_alt_username=no with_crypto_library=openssl
with_gnu_ld=yes with_mem_check=no with_plugindir='$(libdir)/openvpn/plugins' with_sysroot=no


System OpenSSL:

root@anonymous:/usr/local/src/openvpn# openssl version

OpenSSL 1.0.1f 6 Jan 2014


Compiled OpenSSL:

root@anonymous:/usr/local/ssl/bin# ./openssl version

OpenSSL 1.0.1t 3 May 2016


I know it has to be something simple, but I saw other users asking about this on the OpenVPN Forums with no responses as of yet.

jww jww
Answer

Below is the procedure I used to build OpenVPN with OpenSSL 1.0.2. OpenSSL 1.0.1 vs. 1.0.2 vs. 1.1.0 does not matter. Note the use of RPATH's on Linux (OS X would use a different technique).

OpenSSL configuration options are mostly documented at Compilation and Installation | Configure Options on their wiki. I did not find similar for OpenVPN, and ./configure --help was not very helpful. Often, for an Autools project, you need to --with-ssl=<path to ssl root>, but OpenVPN does not appear to have that option. For OpenVPN, the process below went adhoc using Autools CFLAGS.

Both libraries disabled compression because it can leak information. For more details, see Spot me if you can: Uncovering spoken phrases in encrypted VoIP conversations. The problem is the variable bit rate encoding, and the fundamental design is prevalent in other compression libraries (like zlib).

OpenSSL 1.0.2

$ wget https://www.openssl.org/source/openssl-1.0.2h.tar.gz
$ tar xzf openssl-1.0.2h.tar.gz
$ cd openssl-1.0.2h

$ ./config shared no-ssl2 no-ssl3 no-comp enable-ec_nistp_64_gcc_128 -Wl,-rpath=/usr/local/ssl/lib --prefix=/usr/local/ssl
$ make -j 4
$ make test
$ sudo make install

You can check the openssl program is using the expected shared objects with:

$ ldd /usr/local/ssl/bin/openssl
    linux-vdso.so.1 =>  (0x00007ffc36578000)
    libssl.so.1.0.0 => /usr/local/ssl/lib/libssl.so.1.0.0 (0x00007f94b48fb000)
    libcrypto.so.1.0.0 => /usr/local/ssl/lib/libcrypto.so.1.0.0 (0x00007f94b448b000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f94b40c6000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f94b3ec2000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f94b4b6c000)

You can also make sure the new openssl is on-path with the following. Its not required for your issue, however.

$ sudo ln -s /usr/local/ssl/bin/openssl /usr/local/bin/openssl
$ which openssl
/usr/local/bin/openssl

OpenVPN 2.3.11

$ wget https://swupdate.openvpn.org/community/releases/openvpn-2.3.11.tar.gz
$ tar xzf openvpn-2.3.11.tar.gz
$ cd openvpn-2.3.11

$ CFLAGS="-I/usr/local/ssl/include -Wl,-rpath=/usr/local/ssl/lib -L/usr/local/ssl/lib" ./configure --disable-lzo
$ make -j 4

Next, check the OpenVPN program to see what its linking to:

$ find . -type f -name openvpn
./src/openvpn/openvpn
$ ldd ./src/openvpn/openvpn
    linux-vdso.so.1 =>  (0x00007ffc8bfc4000)
    libssl.so.1.0.0 => /usr/local/ssl/lib/libssl.so.1.0.0 (0x00007f74f49f3000)
    libcrypto.so.1.0.0 => /usr/local/ssl/lib/libcrypto.so.1.0.0 (0x00007f74f4583000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f74f437f000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f74f3fba000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f74f4c64000)

Next, run the self tests:

$ make check
...
make[3]: Entering directory `/home/jwalton/openvpn-2.3.11/tests'
./t_client.sh: cannot find 't_client.rc' in build dir ('..')
./t_client.sh: or source directory ('.'). SKIPPING TEST.
SKIP: t_client.sh
Testing cipher AES-128-CBC... OK
Testing cipher AES-128-CFB... OK
Testing cipher AES-128-CFB1... OK
...

Install OpenVPN if it tests OK:

$ sudo make install
$ which openvpn
/usr/local/sbin/openvpn

Finally, check it:

$ /usr/local/sbin/openvpn --version
OpenVPN 2.3.11 x86_64-unknown-linux-gnu [SSL (OpenSSL)] [EPOLL] [MH] [IPv6] built on Aug 17 2016
library versions: OpenSSL 1.0.2h  3 May 2016
Originally developed by James Yonan
Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
...
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