Bug in PE_LoadImage/map_image? [Was: VirtualProtect and app crash]

[Andreas Mohr Usenet 10/01]

Robert Baruch <autophile at starband.net> wrote:
> I used WinDbg to show the memory protections that were placed on the 
> executable image just after it was loaded, and just before the app starts.

> Here is what wine shows:

> View: 0x400000 - 0x765fff 28
>        0x400000 - 0x765fff c-rw-

> Here is what WinDbg shows (manually edited to look like the wine view):

> 0x400000 - 0x400fff c-r-- (PAGE_READONLY)
> 0x401000 - 0x454fff c--W- (PAGE_WRITECOPY)
> 0x455000 - 0x455fff c-rw- (PAGE_READWRITE)
> 0x456000 - 0x457fff c--W- (PAGE_WRITECOPY)
> 0x458000 - 0x458fff c-rw- (PAGE_READWRITE)
> 0x459000 - 0x459fff c-r-- (PAGE_READONLY)
> 0x45a000 - 0x758fff c--W- (PAGE_WRITECOPY)
> 0x759000 - 0x75afff c-r-- (PAGE_READONLY)
> 0x75b000 - 0x75dfff c--W- (PAGE_WRITECOPY)
> 0x75e000 - 0x75efff c-rw- (PAGE_READWRITE)
> 0x75f000 - 0x762fff c-r-x (PAGE_EXECUTE_READ)
> 0x763000 - 0x765fff c-r-- (PAGE_READONLY)

> Remember, this is *before* the app even starts.

> You can see from this that there is a difference between how Windows 
> loads an executable image and how Wine does it. This is why trying to 
> write to 0x75F07E throws an exception under W2K but succeeds under Wine. 
> I guess the W2K exception is the right one.

> Wine developers: Should I attempt a patch, or am I going in the wrong 
> direction?
No, you're entirely correct.
Wine doesn't properly set memory protections of the executable file
in the loader yet.
IMHO this is a pretty damn grave omission.
I'd be rather happy if you actually fixed that :-)
(I once had another program which stumbled on this)

-- 
Andreas Mohr, Renningen, Germany
In case you need to contact me after expiry of temporary email address:
my eternal (hopefully) email address is frqr2001 at the domain sneakemail.com