callReturnExploration.s

Calling functions by Pushing and Jumping

1. Calling functions by Pushing and Jumping callReturnExploration.s
2. LC0: .ascii "%d\n\0" .text .globl _function _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp Program starts here
3. LC0: .ascii "%d\n\0" .text .globl _function _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp 8(%esp) argv 4(%esp) argc (%esp) return addr %esp 28ff2c %ebp old %ebp %eax $0
4. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) 8(%esp) argv 4(%esp) argc (%esp) return addr %esp 28ff2c %ebp old %ebp %eax $0
5. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff28 %ebp old %ebp %eax $0 12(%esp) argv 8(%esp) argc 4(%esp) return addr (%esp) old %ebp
6. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff28 %ebp old %ebp %eax $0 12(%esp) argv 8(%esp) argc 4(%esp) return addr (%esp) old %ebp
7. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff28 %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp
8. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff28 %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp
9. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff20 %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp)
10. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff20 %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp)
11. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff1c %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr
12. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff1c %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr
13. _function:: ... .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) %esp 28ff1c %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr
14. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr %esp 28ff1c %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr
15. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr %esp 28ff1c %ebp 28ff28 %eax $0 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr
16. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr %esp 28ff1c %ebp 28ff28 %eax $99
17. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) 4(%esp) (%esp) $retAddr %esp 28ff1c %ebp 28ff28 %eax $99
18. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp) %esp 28ff20 %ebp 28ff28 %eax $99 %ecx $retAddr
19. _function:: movl $99, %eax # ret popl %ecx jmp *%ecx .globl _main _main:: pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp) %esp 28ff20 %ebp 28ff28 %eax $99 %ecx $retAddr
20. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp) %esp 28ff20 %ebp 28ff28 %eax $99 %ecx $retAddr
21. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp) %esp 28ff20 %ebp 28ff28 %eax $99
22. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) (%esp) %esp 28ff20 %ebp 28ff28 %eax $99
23. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) %esp 28ff20 %ebp 28ff28 %eax $99
24. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) %esp 28ff20 %ebp 28ff28 %eax $99
25. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $99
26. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $99
27. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret %esp 28ff1c %ebp 28ff28 %eax $99 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) $99 4(%esp) $LC0 (%esp) address of next instruction
28. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret %esp 28ff1c %ebp 28ff28 %eax $99 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) $99 4(%esp) $LC0 (%esp) address of next instruction We push the address of the next instruction to the stack.
29. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret %esp 28ff1c %ebp 28ff28 %eax $99 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) $99 4(%esp) $LC0 (%esp) address of next instruction We push the address of the next instruction to the stack. We jump to _printf and do our business
30. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret %esp 28ff1c %ebp 28ff28 %eax $99 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 8(%esp) $99 4(%esp) $LC0 (%esp) address of next instruction We push the address of the next instruction to the stack. We jump to _printf and do our business When finished, _printf jumps to our next instruction
31. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $99
32. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $99
33. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $0
34. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 12(%ebp) argv 8(%ebp) argc 4(%ebp) return addr (%ebp) old %ebp 4(%esp) $99 (%esp) $LC0 %esp 28ff20 %ebp 28ff28 %eax $0
35. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 8(%esp) argv 4(%esp) argc (%esp) return addr %esp 28ff2c %ebp old %ebp %eax $0
36. pushl %ebp movl %esp, %ebp subl $8, %esp # call _function pushl $retAddr jmp _function retAddr: movl %eax, 4(%esp) movl $LC0, (%esp) call _printf movl $0, %eax leave ret 8(%esp) argv 4(%esp) argc (%esp) return addr %esp 28ff2c %ebp old %ebp %eax $0
37. Calling functions by Pushing and Jumping This presentation by Pat Hawks is licensed under a Creative Commons Attribution 4.0 International License callReturnExploration.s