From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KuXuL-0008Vn-Rg for qemu-devel@nongnu.org; Mon, 27 Oct 2008 15:37:45 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KuXuI-0008VS-8W for qemu-devel@nongnu.org; Mon, 27 Oct 2008 15:37:45 -0400 Received: from [199.232.76.173] (port=57765 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KuXuI-0008VN-2a for qemu-devel@nongnu.org; Mon, 27 Oct 2008 15:37:42 -0400 Received: from rv-out-0708.google.com ([209.85.198.246]:25823) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KuXuH-00075I-9y for qemu-devel@nongnu.org; Mon, 27 Oct 2008 15:37:41 -0400 Received: by rv-out-0708.google.com with SMTP id f25so2038016rvb.22 for ; Mon, 27 Oct 2008 12:37:39 -0700 (PDT) Message-ID: Date: Mon, 27 Oct 2008 20:37:39 +0100 From: "andrzej zaborowski" Subject: Re: [Qemu-devel] [PATCH] mmap: add check if requested memory area fits target address space In-Reply-To: <20081027154835.GA10763@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1223892640-15545-13-git-send-email-kirill@shutemov.name> <1224225264-8483-1-git-send-email-kirill@shutemov.name> <20081027154835.GA10763@localhost.localdomain> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Kirill A. Shutemov" Cc: qemu-devel@nongnu.org 2008/10/27 Kirill A. Shutemov : > On Mon, Oct 27, 2008 at 02:08:52PM +0100, andrzej zaborowski wrote: >> On 17/10/2008, Kirill A. Shutemov wrote: >> > Signed-off-by: Kirill A. Shutemov >> > --- >> > 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? I may be misunderstanding but I think the range of valid addresses should depend on target word size, not host (even if the combination where it matters is not yet supported). On a 32-bit host the condition is always false. Cheers