[WIP] Migrate command for Linux meterpreter

[msutovsky-r7]

No description provided.

[dledda-r7]

I woul split this function and the copye and run payload in:

int write_process_memory(pid, remote_address, local_address, size)

and remote_call(pid, remote_address)

also i think the section lookup for executable memory maps should be directly in the find codecave so you have a transparent api that just get you the address of what you need

also you can create something like:
int remote_memory_allocate(int process_pid, int mem_size)

that will be something like

int remote_memory_allocate(int process_pid, int memory_size) {
    int allocated_mem = get_code_cave(memory_size);
    if(allocated_mem > 0) {
         return allocated_mem;
    }
    int wrapper_memory_size = memory_size; // possible compiler issue that's why we wrap it.
    memcpy(mmap_stub + offset_size_memory, &memory_size, sizeof(int));
    int code_cave_addr = get_code_cave(mmap_stub_size);
    write_process_memory(process_pid, code_cave_addr, mmap_stub, mmap_stub_size);
    remote_call(process_pid, code_cave_addr);
    return get_code_cave(memory_size);
}

then the migrate can look like

int migrate(int pid) {
     int migrate_stub_addr = remote_memory_alloc(pid, migrate_stub_size);
     int mettle_addr = remote_memory_alloc(pid, mettle_binimage_size);
     write_process_memory(pid, mettle_addr, mettle_binimage, mettle_binimage_size);
     memcpy(migrate_stub + offset_mettle_addr, &mettle_addr, sizeof(void *));
     wirte_process_memory(pid, migrate_stub_addr, migrate_context, migrate_stub_size);
     remote_call(pid, migrate_stub_addr);
}