Topic 5: Stack-smashing and shellcoding

Question 1

how does a stack grow?

Answer 1

from bottom to top, grows towards lower addresses downwards

Question 2

what is a stack pointer?

Answer 2

points to the top of the stack (its first element), usually stored in RSP/ESP

Question 3

what is a stack used for?

Answer 3

store frame pointer, store local variables, pass function arguments, temporarily store register values, return the address of caller function

Question 4

what is a stack frame?

Answer 4

includes all function-local data, starts below the return address and stops at the stack pointer

Question 5

what is a frame pointer?

Answer 5

aka base pointer, marks the highest address in the frame, commonly stored in RBP/EBP

Question 6

steps of a function call?

Answer 6

1. prepare arguments
2. make the call
3. function prologue
   
   1. save RBP/EBP
   2. setup new RBP/EBP
4. callee saves registers that need to be preserved
5. callee allocates stack space