if we compile some C code with gcc we often see the following assembly result
0x08048494 <+0>: push ebp
0x08048495 <+1>: mov ebp,esp
0x08048497 <+3>: and esp,0xfffffff0
0x0804849a <+6>: sub esp,0x130
0x080484a0 <+12>: mov eax,DWORD PTR [ebp+0xc]
0x080484a3 <+15>: mov DWORD PTR [esp+0x1c],eax
0x080484a7 <+19>: mov eax,gs:0x14
this is a simple function prologue. from the +19 line, we can see the stack protector value is obtained from gs:0x14. my question is, can I know the actual virtual address of gs:0x14 with gdb? the gs segment selector value indicates the offset from GDT however, a user level process such as gdb cannot access the GDT information. how can I figure out the base address of gs segment using gdb or other debugger? is this impossible?
thank you in advance.
