How to compile statically linked OpenVPN client for ARMv5

README.md

How to compile statically linked OpenVPN client for ARMv5

You need to install ARMv5 gcc cross compiler: apt-get install gcc-arm-linux-gnueabi

You have to define a directory (via --prefix) where all of your binaries will be installed (copied). In the guide I use the following: /home/user/vpn_compile

OpenSSL

1. Download the source: wget https://www.openssl.org/source/openssl-1.0.2j.tar.gz
2. Extract it and change the working directory: tar -xvf openssl-1.0.2j.tar.gz && cd openssl-1.0.2j
3. Configure it: ./Configure gcc -static -no-shared --prefix=/home/user/vpn_compile --cross-compile-prefix=arm-linux-gnueabi-
4. Compile: make
5. Install: make install

LZO

1. Download the source: wget http://www.oberhumer.com/opensource/lzo/download/lzo-2.09.tar.gz
2. Extract it and change the working directory: tar -xvf lzo-2.09.tar.gz && cd lzo-2.09
3. Configure it: ./configure --prefix=/home/user/vpn_compile --enable-static --target=arm-linux-gnueabi --host=arm-linux-gnueabi --disable-debug
4. Compile: make
5. Install: make install

OpenVPN

1. Download the source: wget https://swupdate.openvpn.org/community/releases/openvpn-2.3.12.tar.gz
2. Extract it and change the working directory: tar -xvf openvpn-2.3.12.tar.gz && cd openvpn-2.3.12
3. Configure it: ./configure --target=arm-linux-gnueabi --host=arm-linux-gnueabi --prefix=/home/user/vpn_compile --disable-server --enable-static --disable-shared --disable-debug --disable-plugins OPENSSL_SSL_LIBS="-L/home/user/vpn_compile/lib -lssl" OPENSSL_SSL_CFLAGS="-I/home/user/vpn_compile/include" OPENSSL_CRYPTO_LIBS="-L/home/user/vpn_compile/lib -lcrypto" OPENSSL_CRYPTO_CFLAGS="-I/home/user/vpn_compile/include" LZO_CFLAGS="-I/home/user/vpn_compile/include" LZO_LIBS="-L/home/user/vpn_compile/lib -llzo2"
4. Compile: make LIBS="-all-static"
5. Install: make install

Your OpenVPN client is here: /home/user/vpn_compile/sbin/openvpn

Make sure this is what you need:

$ file /home/user/vpn_compile/sbin/openvpn
/home/user/vpn_compile/sbin/openvpn: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), statically linked, for GNU/Linux 3.2.0, BuildID[sha1]=e6fd2008c129fef90ed9826e3ffb9d53e83eb42c, not stripped

Versions

Build system:

$ uname -rm
4.4.0-45-generic x86_64
$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.1 LTS"
$ arm-linux-gnueabi-gcc --version
arm-linux-gnueabi-gcc (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.1) 5.4.0 20160609

Target system:

$ uname -rm
3.2.34 armv5tejl
$ openvpn --version
OpenVPN 2.3.12 arm-unknown-linux-gnueabi [SSL (OpenSSL)] [LZO] [EPOLL] [MH] [IPv6] built on Oct 27 2016
library versions: OpenSSL 1.0.2j  26 Sep 2016, LZO 2.09
Originally developed by James Yonan
Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <[email protected]>
Compile time defines: enable_crypto=yes enable_crypto_ofb_cfb=yes enable_debug=no enable_def_auth=yes enable_dlopen=unknown enable_dlopen_self=unknown enable_dlopen_self_static=unknown enable_fast_install=needless enable_fragment=yes enable_http_proxy=yes enable_iproute2=no enable_libtool_lock=yes enable_lzo=yes enable_lzo_stub=no 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=no enable_plugin_down_root=no enable_plugins=no enable_port_share=yes enable_selinux=no enable_server=no enable_shared=no enable_shared_with_static_runtimes=no enable_small=no enable_socks=yes enable_ssl=yes enable_static=yes enable_strict=no enable_strict_options=no enable_systemd=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

Static libcapng required for building with OpenVPN 2.6.*:

#libCAP-NG
cd /home/source
wget https://github.com/stevegrubb/libcap-ng/archive/refs/tags/v0.8.5.tar.gz
tar xvzf v0.8.5.tar.gz
cd libcap-ng-0.8.5
./autogen.sh
./configure --prefix=/home/openvpn --enable-static --target=arm-linux-gnueabi --host=arm-linux-gnueabi
make
make install

#OpenVPN 2.6.x add/replace following
./configure ... LIBCAPNG_CFLAGS="-I/home/openvpn/include" LIBCAPNG_LIBS="-L/home/openvpn/lib -lcap-ng ..."
make LIBS="-all-static -lcap-ng"

you can get rid of

checking for LIBCAPNG... no
configure: error: libcap-ng package not found. Is the development package and pkg-config installed?

with sudo apt install libcap-ng-dev, but cannot avoid make LIBS="-all-static" to fail with

/home/source/openvpn-2.6.13/src/openvpn/platform.c:246: undefined reference to `capng_clear'
/usr/bin/ld: /home/source/openvpn-2.6.13/src/openvpn/platform.c:247: undefined reference to `capng_update'
/usr/bin/ld: /home/source/openvpn-2.6.13/src/openvpn/platform.c:257: undefined reference to `capng_change_id'
collect2: error: ld returned 1 exit status
make[3]: *** [Makefile:670: openvpn] Error 1
make[3]: Leaving directory '/home/source/openvpn-2.6.13/src/openvpn'
make[2]: *** [Makefile:439: all-recursive] Error 1
make[2]: Leaving directory '/home/source/openvpn-2.6.13/src'
make[1]: *** [Makefile:617: all-recursive] Error 1
make[1]: Leaving directory '/home/source/openvpn-2.6.13'
make: *** [Makefile:505: all] Error 2

refer: OpenVPN/openvpn#586

I managed to succesfully build OpenVPN 2.6.14 for MIPS architecture on a clean Debian 12 machine
The final binary can be found at /work/vpn_compile/sbin/openvpn

apt update
apt install -y wget git net-tools build-essential autoconf pkg-config libtool gcc-mips-linux-gnu bison flex

mkdir /work
cd /work


# OpenSSL
wget https://github.com/openssl/openssl/releases/download/openssl-3.0.17/openssl-3.0.17.tar.gz
tar -xvf openssl-3.0.17.tar.gz
cd openssl-3.0.17

./Configure gcc -static -no-shared --prefix=/work/vpn_compile --cross-compile-prefix=mips-linux-gnu-
make -j24
make install_sw

cd ..


# LZO
wget http://www.oberhumer.com/opensource/lzo/download/lzo-2.09.tar.gz
tar -xvf lzo-2.09.tar.gz
cd lzo-2.09

./configure --prefix=/work/vpn_compile --enable-static --disable-shared --target=mips-linux-gnu --host=mips-linux-gnu --disable-debug
make -j24
make install

cd ..


# LZ4
wget https://github.com/lz4/lz4/archive/v1.9.2.tar.gz
tar xvzf v1.9.2.tar.gz
cd lz4-1.9.2

make BUILD_STATIC=yes CC=mips-linux-gnu-gcc DLLTOOL=mips-linux-gnu-dlltool OS=mips-linux-gnu -j24
PREFIX=/work/vpn_compile make install

cd ..

# libcap-ng
wget https://github.com/stevegrubb/libcap-ng/archive/refs/tags/v0.8.5.tar.gz
tar xvzf v0.8.5.tar.gz
cd libcap-ng-0.8.5

./autogen.sh
./configure --prefix=/work/vpn_compile --enable-static --disable-shared --target=mips-linux-gnu --host=mips-linux-gnu
make -j24
make install

cd ..


# libnl-3 (641cd0e77761ed44f1d19dd073766c99732ddd5a)
git clone https://github.com/thom311/libnl
cd libnl

./autogen.sh
./configure --prefix=/work/vpn_compile --enable-static --disable-shared --target=mips-linux-gnu --host=mips-linux-gnu
make -j24
make install

cd ..


# OpenVPN
wget https://swupdate.openvpn.org/community/releases/openvpn-2.6.14.tar.gz
tar -xvf openvpn-2.6.14.tar.gz
cd openvpn-2.6.14

./configure --target=mips-linux-gnu --host=mips-linux-gnu --prefix=/work/vpn_compile --enable-static --disable-shared --disable-debug --disable-plugins OPENSSL_LIBS="-L/work/vpn_compile/lib -lssl" OPENSSL_CFLAGS="-I/work/vpn_compile/include" OPENSSL_CRYPTO_LIBS="-L/work/vpn_compile/lib -lcrypto" OPENSSL_CRYPTO_CFLAGS="-I/work/vpn_compile/include" LZO_CFLAGS="-I/work/vpn_compile/include" LZO_LIBS="-L/work/vpn_compile/lib -llzo2" LZ4_CFLAGS="-I/work/vpn_compile/include" LZ4_LIBS="-L/work/vpn_compile/lib -llz4" LIBNL_GENL_CFLAGS="-I/work/vpn_compile/include" LIBNL_GENL_LIBS="-L/work/vpn_compile/lib -lnl-genl-3" LIBCAPNG_CFLAGS="-I/work/vpn_compile/include" LIBCAPNG_LIBS="-L/work/vpn_compile/lib -lcap-ng" CPPFLAGS="-I/work/vpn_compile/include/libnl3"

make LIBS="-L/work/vpn_compile/lib -all-static -lssl -lcrypto -llzo2 -llz4 -lcap-ng -lnl-3 -lnl-genl-3" -j24
make install