Exercise 5 and 6
Determine which method are actually loaded from the MediaCodec.apk shared libraries.
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Reverse Engineering
Determine which method are actually loaded from the MediaCodec.apk shared libraries.
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Do we have interfaces matching the functions we know to be native?
int bspatch(String str, String str2, String str3).
void m2054a(String s)
strings lib/x86/librrnad.so |grep "(Ljava/lang/String"
Do we have dynamic linking? Let's look for methods following the known pattern.
nm –gD lib/x86/librrnad.so |grep java_, none is found.
Conclusion:
We have artefacts pointing to Java types.
We do not indicate Dynamic Linking.
Open ghidra, create a new project and load a library.
Several interesting functions were discovered.
JNI_Load,
registerNatives, registerNativeMethods,
FUN_00011230, FUN_000270, FUN_11290, FUN_112b4,
native_setAppKey
Coherent with Static Linking.
Explore the functions, exports, Classes, etc… lots of info.
Graph -> Block Flow from JNI_OnLoad.
Decompile JNI_OnLoad
Loading the jni_all.gdt, and retyping the variables, allows the resolution of symbols, such as the FindClass.
registerNativesregisterNativeMethods
