asm injection stub

Lets check what this stub should do being injected in some linux process via __malloc_hook/__free_hook (btw this implicitly means than you cannot use this dirty hack for processes linked with musl or uClibc - they just don't have those hooks)

• bcs our stub can be called from two different hooks we should store somewhere via which entry point we was called
• restore old hooks values
• call dlopen/dlsym and then target function (and pass it address of injection stub for delayed munmap. No, you can't free those memory directly in your target function - try to guess why)
  
• get right old hook and jump to it if it was installed or just return to code called __malloc_hook somewhere in libc

So I collected all parameters to do job in table dtab consisting from 6 pointers

1. __malloc_hook address
2. old value of __malloc_hook
3. __free_hook address
4. old value of __free_hook
5. pointer to dlopen
6. pointer to dlsym
   

after those table we also has couple of string constants for injected.so full path and function name. Also bcs we must setup 2 entry point I decided to put 1 byte with distance between first and second (to make injection logic more universal) right after dtab. Sounds easy, so lets check how this logic can be implemented on some still living processors (given that RIP alpha, sparc, hp-pa etc)