Re: [Qemu-devel] [Bug 661696] Re: incomplete emulation of fstenv under TCG

[Chalkerx]

Thanks for porting the patch.

This is the mailing thread I started back in 2010 with that patch:
http://lists.gnu.org/archive/html/qemu-devel/2010-11/msg02497.html
That thread has some problems noted.

Sadly, I did not have enough free time to investigate all the other
places that should be fixed for proper fpip/etc. support.

That patch seems to be related:
https://patchwork.kernel.org/patch/871232/, but is kvm only. You could
try contacting the person that did the patch for kvm.

Nikita Skovoroda.

2013/6/29 Morten Shearman Kirkegaard <address@hidden>:
> The bug is still present in the newly released QEMU-1.5.1. I've ported
> Chalkerx's patch to this release as well. See attached patch.
>
> Is there a problem with this patch, since it has not been committed?
>
> // MOKI
>
> ** Patch added: "patch-qemu-1.5.1-fpip.diff"
>    
> https://bugs.launchpad.net/qemu/+bug/661696/+attachment/3718352/+files/patch-qemu-1.5.1-fpip.diff

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https://bugs.launchpad.net/bugs/661696

Title:
  incomplete emulation of fstenv under TCG

Status in QEMU:
  New

Bug description:
  Steps to reproduce:

  1) Install Windows (tried XP and 7) in qemu (tried qemu without kvm
  and qemu-kvm).

  2) Get OllyDbg ( http://ollydbg.de/odbg200.zip ).

  3) Use some Metasploit-encoded file, example included.

  It is not a virus!

  File was generated with Metasploit, command (if i remember it right):
  `msfpayload windows/exec cmd=notepad R | msfencode -e
  x86/shikata_ga_nai -t exe -o cmd_exec_notepad.shikata_ga_nai.exe`.

  4) Launch the file under Windows in qemu, make sure it opens a
  notepad.

  5) Open file under OllyDbg, run (F9) it there. It opens a notpad.
  Close OllyDbg.

  6) Open file under OllyDbg, trace over (Ctrl+F12) it there. It fails with 
`Access violation when writing to [some address]`.
  Command: 316A 13, XOR DWORD PTR DS:[EDX+13],EBP 

  Under native Windows, the trace over command works fine.

  Under VMware the trace works fine.
  Under VirtualBox it also fails (checked in the spring).

  $ qemu-kvm --version
  QEMU PC emulator version 0.12.5 (qemu-kvm-0.12.5), Copyright (c) 2003-2008 
Fabrice Bellard

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