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[209.132.180.67]) by mx.google.com with ESMTP id dc16si52825ejb.192.2019.11.20.11.28.55; Wed, 20 Nov 2019 11:29:20 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=codethink.co.uk Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727706AbfKTT1d (ORCPT + 99 others); Wed, 20 Nov 2019 14:27:33 -0500 Received: from imap1.codethink.co.uk ([176.9.8.82]:34242 "EHLO imap1.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727003AbfKTT1d (ORCPT ); Wed, 20 Nov 2019 14:27:33 -0500 Received: from [167.98.27.226] (helo=xylophone) by imap1.codethink.co.uk with esmtpsa (Exim 4.84_2 #1 (Debian)) id 1iXVdQ-0002RA-UC; Wed, 20 Nov 2019 19:27:29 +0000 Message-ID: <41baf20a190039443cb2b82aea0c2a8ec872cfed.camel@codethink.co.uk> Subject: Re: [Y2038] [PATCH 6/8] lp: fix sparc64 LPSETTIMEOUT ioctl From: Ben Hutchings To: Arnd Bergmann , y2038@lists.linaro.org, Greg Kroah-Hartman Cc: "Gustavo A. R. Silva" , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Bamvor Jian Zhang , Thomas Gleixner , Sudip Mukherjee Date: Wed, 20 Nov 2019 19:27:27 +0000 In-Reply-To: <20191108203435.112759-7-arnd@arndb.de> References: <20191108203435.112759-1-arnd@arndb.de> <20191108203435.112759-7-arnd@arndb.de> Organization: Codethink Ltd. Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5-1.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2019-11-08 at 21:34 +0100, Arnd Bergmann wrote: > The layout of struct timeval is different on sparc64 from > anything else, and the patch I did long ago failed to take > this into account. > > Change it now to handle sparc64 user space correctly again. > > Quite likely nobody cares about parallel ports on sparc64, > but there is no reason not to fix it. > > Cc: stable@vger.kernel.org > Fixes: 9a450484089d ("lp: support 64-bit time_t user space") > Signed-off-by: Arnd Bergmann > --- > drivers/char/lp.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/char/lp.c b/drivers/char/lp.c > index 7c9269e3477a..bd95aba1f9fe 100644 > --- a/drivers/char/lp.c > +++ b/drivers/char/lp.c > @@ -713,6 +713,10 @@ static int lp_set_timeout64(unsigned int minor, void __user *arg) > if (copy_from_user(karg, arg, sizeof(karg))) > return -EFAULT; > > + /* sparc64 suseconds_t is 32-bit only */ > + if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall()) > + karg[1] >>= 32; > + > return lp_set_timeout(minor, karg[0], karg[1]); > } > It seems like it would make way more sense to use __kernel_old_timeval. Then you don't have to explicitly handle the sparc64 oddity. As it is, this still over-reads from user-space which might result in a spurious -EFAULT. Ben. -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom