From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:54244)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <laurent@vivier.eu>) id 1ZsMGk-0007zV-49
	for qemu-devel@nongnu.org; Fri, 30 Oct 2015 22:51:50 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <laurent@vivier.eu>) id 1ZsMGf-0004qT-4Z
	for qemu-devel@nongnu.org; Fri, 30 Oct 2015 22:51:50 -0400
Received: from mout.kundenserver.de ([212.227.126.130]:59716)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <laurent@vivier.eu>) id 1ZsMGe-0004qL-Rh
	for qemu-devel@nongnu.org; Fri, 30 Oct 2015 22:51:45 -0400
References: <1441497448-32489-1-git-send-email-T.E.Baldwin99@members.leeds.ac.uk>
	<1441497448-32489-2-git-send-email-T.E.Baldwin99@members.leeds.ac.uk>
	<CAFEAcA8vUM_eSDxHOKocqrr488+tk+eOMQePaQK0fCoWy_fmBw@mail.gmail.com>
	<4d9a4d2f-5c12-48e3-964c-65e0922950d8@iki.fi>
From: Laurent Vivier <laurent@vivier.eu>
Message-ID: <56342CB4.3050003@vivier.eu>
Date: Sat, 31 Oct 2015 03:51:32 +0100
MIME-Version: 1.0
In-Reply-To: <4d9a4d2f-5c12-48e3-964c-65e0922950d8@iki.fi>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [Qemu-devel] [PATCH 01/34] linux-user: Fix array bounds in
 errno conversion
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Riku Voipio <riku.voipio@iki.fi>, Peter Maydell <peter.maydell@linaro.org>
Cc: Timothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>, QEMU Developers <qemu-devel@nongnu.org>



Le 12/10/2015 15:42, Riku Voipio a écrit :
> On perjantaina 11. syyskuuta 2015 13.59.29 EEST, Peter Maydell wrote:
>> On 6 September 2015 at 00:56, Timothy E Baldwin
>> <T.E.Baldwin99@members.leeds.ac.uk> wrote:
>>> Check array bounds in host_to_target_errno() and target_to_host_errno().
>>>
>>> Signed-off-by: Timothy Edward Baldwin
>>> <T.E.Baldwin99@members.leeds.ac.uk>
>>> ---
>>>  linux-user/syscall.c | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-) ...
>>
>> Maybe we should also check that the passed in error value is
>> not negative? (Given the errno-is-positive/syscall-return-negative
>> conventions, it's an easy mistake to make...)
> 
> I've applied a version of this patch that implements this by setting the
> function argument to unsigned
> 
> Riku
> 
> 
This patch breaks get_errno().

On a 64bit target, if errno is 22, host_to_target_errno(22) is (unsigned
int)-22 = 0xffffffea, and get_errno() is (abi_long)0xffffffea =
0x000000000xffffffea = 4294967274. It is not negative, and thus is not
an error.

host_to_target_errno() and target_to_host_errno() must stay signed.

Laurent