Re: ntoskrnl.exe: Implement MmIsAddressValid (bug 11082)

[Detlef Riekenberg]

On Di, 2008-03-18 at 09:09 +0800, Dmitry Timoshkov wrote:
> "Detlef Riekenberg"  wrote:
> > - len = VirtualQuery(VirtualAddress, &info, sizeof(MEMORY_BASIC_INFORMATION));
> > -
> > - if ((len == sizeof(MEMORY_BASIC_INFORMATION)) &&
> > -
> >    (info.Protect & (PAGE_READWRITE || PAGE_EXECUTE_READWRITE)) &&
> > -
> >    ((info.Protect & PAGE_NOACCESS) == 0) &&
> > -
> >    (info.Type & MEM_COMMIT))
> > - {
> > -
> >    return TRUE;
> > - }
>
> Besides the already pointed out '||' vs. '|' mismatch your code doesn't
> handle PAGE_READONLY and others implying read-only access. Probably checking
> for PAGE_NOACCESS and MEM_COMMIT should be enough.

This is not enough, since PAGE_READONLY will Pagefault on Write.
> From OSR, the result is only TRUE, when the Address does not pagefault

on read or write access:
http://www.osronline.com/DDKx/kmarch/k106_3vle.htm

Thanks for your review.