Re: Cross compilation with openssl > 1.0.2

[Jakub Jelen <jjelen@xxxxxxxxxx>]

On 5/19/21 1:39 PM, Andrey Strunin wrote:
> Hi,
>
> Actually I just built the whole library (before even reading your 
> message).
> I did it with nasty hack of disabling the whole libcrypto-compat.c 
> with `#if 0`.
>
> I think there is some problem with detection OPENSSL version when 
> cross compiling (in my logs I saw that it detected 1.0.2k. It looks 
> like it found a host library...)
>
> UPD:
> Just added this line to my toolchain cmake file and removed `#if 0` 
> hack from libcrypto-compat.c:
> SET(OPENSSL_VERSION 3.0.0)
>
> Everything builds great.
>
> Thanks,
> Andrey
>
> ср, 19 мая 2021 г. в 13:25, Anderson Sasaki <ansasaki@xxxxxxxxxx 
> <mailto:ansasaki@xxxxxxxxxx>>:
>
>
>
>     On Wed, May 19, 2021 at 11:26 AM Andrey Strunin
>     <acrapmonster@xxxxxxxxx <mailto:acrapmonster@xxxxxxxxx>> wrote:
>
>         Thank you for the response,
>
>         I am using my own cmake toolchain file that sets compiler and
>         sysroot. It worked great when it was openssl 1.0.2 in sysroot.
>
>         Here is the content of my toolchain.cmake file:
>
>         #CMAKE Toolchain file for PowerPC
>         # this one is important
>         SET(CMAKE_SYSTEM_NAME Linux)
>         #this one not so much
>         SET(CMAKE_SYSTEM_VERSION 1)
>
>         # specify the cross compiler
>         SET(CMAKE_C_COMPILER
>         /localhome/new_sdk/gnss_tcc-glibc_cgl/x86-linux2/ppc_e500v2-target-linux-gnu-gcc)
>         SET(CMAKE_CXX_COMPILER
>         /localhome/new_sdk/gnss_tcc-glibc_cgl/x86-linux2/ppc_e500v2-target-linux-gnu-g++)
>
>         # where is the target environment
>         SET(CMAKE_FIND_ROOT_PATH
>          /localhome/new_sdk/gnss_tcc-glibc_cgl/sysroot)
>
>         # Local plaform dependent toolchain outputs
>         SET(CMAKE_LOCAL_BASE_ROOT_PATH
>          /localhome/new_sdk/gnss_tcc-glibc_cgl/sysroot)
>
>         # search for programs in the build host directories
>         SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
>         # for libraries and headers in the target directories
>         SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
>         SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
>
>         Here is the output with openssl related errors:
>         https://pastebin.com/raw/NrMXi5M8
>         <https://pastebin.com/raw/NrMXi5M8>
>
>         I should have clarified the version of libssh I am using. It's
>         the latest 0.9.5. However, I have the same build issue (maybe
>         with slightly different errors, but still related to openssl)
>         with older versions (such as 0.8.9).
>
>         Thanks,
>         Andrey
>
>
>     Hello,
>
>     After checking the log you linked, I suspect cmake failed to
>     detect the OpenSSL version and included libcrypto-compat.c into
>     the sources. In my machine (Fedora 33), I see this line when
>     running cmake to generate the configuration:
>
>     -- Found OpenSSL: /usr/lib64/libcrypto.so (found suitable version
>     "1.1.1k", minimum required is "1.0.1")
>
>     Please check if cmake found the dynamic library you expected.
>     Maybe you will have to tweak the places where cmake searches for
>     libraries in your custom environment.
>
>     In my machine, the "OPENSSL_FOUND" and "OPENSSL_VERSION" are set
>     by the cmake module "FindOpenSSL.cmake" which is located at
>     /usr/share/cmake/Modules.
>
>     Regards,
>     Anderson
It would be useful to debug the issue further to provide a proper 
solutions also for cross-compiling. We just use normal find_package():

https://gitlab.com/libssh/libssh-mirror/-/blob/master/CMakeLists.txt#L61

It would be worth checking what it does for openssl and if there is 
something to adjust for cross-compiling. In Fedora, I have 
/usr/share/cmake/Modules/FindOpenSSL.cmake, which handles this. First, 
make sure it is up-to-date. From my fast read-through, I would consider 
using OPENSSL_ROOT_DIR pointing to the place where your openssl is 
installed.

Regards,

--
Jakub Jelen
Senior Software Engineer
Crypto Team, Security Engineering
Red Hat, Inc.