How to use static linking with OpenSSL in C/C++

Question

I wrote simple apps with Openssl in C and C++. I compile them like this:

gcc openssltest.c -o openssltest -lcrypto
g++ openssltest.cpp -o openssltest -lcrypto

And its all ok but only, when you have Openssl installed.

I would like to compile it that I can run them on OS where theres no Openssl installend (linux-like OS). I tried this:

gcc -c openssltest.c -lcrypto -static
gcc openssltest.o -o openssltest -lcrypto -static

and same for C++:

g++ -c openssltest.cpp -lcrypto -static
g++ openssltest.o -o openssltest -lcrypto -static

But have those errors:

/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
(.text+0x19): undefined reference to `dlopen'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
(.text+0x2c): undefined reference to `dlsym'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
(.text+0x37): undefined reference to `dlclose'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func':
(.text+0x354): undefined reference to `dlsym'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func':
(.text+0x3fb): undefined reference to `dlerror'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_var':
(.text+0x474): undefined reference to `dlsym'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_var':
(.text+0x52e): undefined reference to `dlerror'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
(.text+0x5a2): undefined reference to `dlopen'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
(.text+0x60b): undefined reference to `dlclose'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
(.text+0x638): undefined reference to `dlerror'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr':
(.text+0x6cd): undefined reference to `dladdr'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr':
(.text+0x731): undefined reference to `dlerror'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_unload':
(.text+0x78a): undefined reference to `dlclose'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_free':
(.text+0x4d): undefined reference to `inflateEnd'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_free':
(.text+0x6b): undefined reference to `deflateEnd'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_ctrl':
(.text+0x284): undefined reference to `deflate'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_ctrl':
(.text+0x342): undefined reference to `zError'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_expand_block':
(.text+0x411): undefined reference to `inflate'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_compress_block':
(.text+0x4ca): undefined reference to `deflate'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_finish':
(.text+0x51f): undefined reference to `inflateEnd'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_finish':
(.text+0x528): undefined reference to `deflateEnd'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_init':
(.text+0x5d7): undefined reference to `inflateInit_'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `zlib_stateful_init':
(.text+0x659): undefined reference to `deflateInit_'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_read':
(.text+0x893): undefined reference to `inflate'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_read':
(.text+0x90d): undefined reference to `zError'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_read':
(.text+0x97c): undefined reference to `inflateInit_'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_write':
(.text+0xa6f): undefined reference to `deflate'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_write':
(.text+0xaec): undefined reference to `zError'
/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/libcrypto.a(c_zlib.o): In function `bio_zlib_write':
(.text+0xb7e): undefined reference to `deflateInit_'
collect2: error: ld returned 1 exit status

How can I make this? I remember that a while ago I did this but now, erm, forgot how to do it. Im on Ubuntu 13.04 x64 - can it be an issue?

Answer 1

I had a similar issue trying to statically compile a simple DES program using the openssl lib. I used -lcrypto -lz -ldl -static-libgcc and it worked for me. No warnings or errors.

Answer 2

You need to be aware that libraries need to availiable as statically linked *.a files. If they are not, then compilation will either fail or you end up with a dynamically linked executable.

If this gets too much PITA (all the libraries dependencies need to be statically compiled to, and their deps too and so on) use something like buildroot

Answer 3

I had the same problem as you. Here's the command that solved it for me:

gcc yourfile.c -o yourfile -static -lcrypto -lz -ldl

It generates this warning:

/usr/lib/gcc/i686-linux-gnu/4.7/../../../i386-linux-gnu/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup': (.text+0x1b): warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking

but the executable still works.

Answer 4

A hotfix: try to link in libdl statically, too.

If this not works, IMHO your libcrypto.a is bad compiled.