Introducing Stub Code

[pdamian]

Tasks:

• [x] Create binary stub code for the strlen function (ARMv7, position-independent)
• [ ] Compare strlen implementations of glibc, uClibc-ng and stub in Triton core
• [x] Use morion's hooking mechanism instead of the (future) stubs within Triton's core
• [x] Use morion's hooking mechanism instead of patching the PLT
• [x] Create some tests

References:

• https://github.com/JonathanSalwan/Triton/issues/1156#issue-1299699552
• https://github.com/JonathanSalwan/Triton/blob/dev-v1.0/src/stubs/triton-stubs.c

[pdamian]

Stubs are mainly useful in symbolic emulation mode (static symbolic execution - SSE). They are primarily intended to return correct concrete result values of external library calls. In morion we use a concolic exeuction mode (dynamic symbolic execution - DSE) and can therefore use the concrete result of the actual library call.