Re: [Qemu-devel] [PATCH] mmap: add check if requested memory area fits target address space

[Kirill A. Shutemov]

On Mon, Oct 27, 2008 at 02:08:52PM +0100, andrzej zaborowski wrote:
> On 17/10/2008, Kirill A. Shutemov <address@hidden> wrote:
> > Signed-off-by: Kirill A. Shutemov <address@hidden>
> >  ---
> >   linux-user/mmap.c |    5 +++++
> >   1 files changed, 5 insertions(+), 0 deletions(-)
> >
> >  diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> >  index bc20f4b..9a2f355 100644
> >  --- a/linux-user/mmap.c
> >  +++ b/linux-user/mmap.c
> >  @@ -388,6 +388,11 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, 
> > int prot,
> >          end = start + len;
> >          real_end = HOST_PAGE_ALIGN(end);
> >
> >  +        if ((unsigned long)start + len > (abi_ulong) -1) {
> >  +            errno = EINVAL;
> >  +            goto fail;
> >  +        }
> 
> I'm being picky but this would prevent the last byte from being used?
> :p  (or the last page because len is aligned?)

No, it returns error if start + len is more than 0xFFFFFFFF (32-bit
target).

> 
> I'm not sure unsigned long is the best choice.

Why?

-- 
Regards,  Kirill A. Shutemov
 + Belarus, Minsk
 + ALT Linux Team, http://www.altlinux.com/

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