External library and JNI with Android: dlopen failed: library "libcrypto.so.1.1" not found, even with SONAME set correctly

Question

I've cross-compiled OpenSSL for Android (x86 and arm). I added the .so files (respectively: libcrypto.so and libssl.so) to the generated .apk file by using a jniLibs through build.gradle. I've checked, and the .so files are properly packed in the generated .apk.

Now, the .so files are properly named:

$ objdump -p libssl.so | grep SONAME
  SONAME               libssl.so.1.1
$ objdump -p libcrypto.so | grep SONAME
  SONAME               libcrypto.so.1.1

And yet, when the code is executed, I get the following error: java.lang.UnsatisfiedLinkError: dlopen failed: library "libcrypto.so.1.1" not found.

I mentioned in the title that I'm using JNI, because the issue actually comes when one of the JNI module is created.

The structure of my project is as follow:

• I have a JNILibrary Android Studio project, whose goal is to generate an Android library (.aar file). It has 2 .java classes: AgentWrapper.java, and ClientWrapper.java, which both expose native methods. The CMakeLists.txt file compiles the C (JNI) code, and the generated .so files (libagent.so and libclient.so) are bundled in the final .aar.

• This JNILibrary Android Studio project also contains a LibraryWrapper.java class ; it contains abstraction methods that handle the native methods implemented in JNI (accessible through AgentWrapper.java and ClientWrapper.java).

• The C code of AgentWrapper.java uses the OpenSSL library. It's dependant of both libcrypto.so and libssl.so, which are both bundled in the generated .aar.

With that done, I create another Android Studio project, JNILibraryTestApk. I import the previously generated .aar library, and use it inside my MainActivity: LibraryWrapper.TestMethod();. This method calls a Client method, then a Agent method. When it reaches the Agent method, and tries to load the libcryto.so file... The application crashes and I am greeted by the usual error message.

Note: if I remove the part that calls a method from the Agent library (which is the one using libcrypto.so.1.1), the application runs fine, which proves that the issue is probably only coming from the libcrypto.so[.1.1] file missing/not found.

If anyone can help me with this, I'd be really grateful, I'm starting to lose my mind on this!

Cheers

Answer 1

I believe that if the file is called "libcrypto.so", you should request it using:

System.loadLibrary("crypto");

Answer 2

Based on information such as:

https://stackoverflow.com/a/55080634/4959635

Android's Gradle does not support versioned .sos so you should aim to use and build unversioned libraries.