Re: Clever ways to hide a compare

David J. Craig wrote:
> I did say if you are using DOS. This won't work for Windows NT
> unless you know a lot about the internals of the kernel and then even
> self modifying code is possible with device driver support. How can
> you have a buffer overflow if you write the code correctly. You are
> setting things based upon decisions you have made and not on user
> input. It might be a side effect of user input in that you might
> change the code flow based upon that input, but you will have checked
> and validated the input before you start making these type of
> modifications.

You can do self modifying code on NT without any problems, you just have to
either modify the PE header on disk or use VirtualProtect to allow writing
to your .text section. And you could even do "running line" trickery if you
want, using SEH.


.

Relevant Pages

  • Re: Clever ways to hide a compare
    ... I did say if you are using DOS. ... decisions you have made and not on user input. ... If this is DOS and not Windows NT, ... >>> Suppose you are writing a protection scheme, and need to compare 2 ...
    (comp.lang.asm.x86)
  • Re: Clever ways to hide a compare
    ... > decisions you have made and not on user input. ... >> David J. Craig yazdi: ... If this is DOS and not Windows NT, ...
    (comp.lang.asm.x86)
  • JOptionPane
    ... i do a simple program which runs in Dos. ... When user input a keyword, ... dialog box will pop up but it hides behind all the windows forms i have ...
    (comp.lang.java.programmer)
  • Re: Can data be executed?
    ... >> self modifying code or data that could be executed ... >> without restriction was a security risk. ... Windows allows code to be ... operating systems. ...
    (borland.public.delphi.language.basm)