Question

As an assignment for a security class, I am trying to use __asm__('jmp 0xbffff994'); in my code, but when I disassemble things in gdb, the instruction is changed to jmp 0xc8047e2a. Any idea why and how can I jump to a particular address?

Answer 1

Probably because it’s a jumping to a relative address, and the linker or loader has moved your code. Try putting the address into a variable, and then do:

jmp dword [var] 

or alternatively:

push 0xbffff994 ret