Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751793AbbKIQCx (ORCPT ); Mon, 9 Nov 2015 11:02:53 -0500 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:43459 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989AbbKIQCv (ORCPT ); Mon, 9 Nov 2015 11:02:51 -0500 Date: Mon, 9 Nov 2015 16:01:37 +0000 From: Russell King - ARM Linux To: Jungseung Lee Cc: Shailendra Verma , Greg Kroah-Hartman , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Riley Andrews , Laura Abbott , Shailendra Verma , Dan Carpenter , Mitchel Humpherys , Sumit Semwal , "Kirill A. Shutemov" , Gioh Kim , Rasmus Villemoes , Shawn Lin , Markus Elfring , "linux-arm-kernel@lists.infradead.org" , devel@driverdev.osuosl.org, Ravikant Bijendra Sharma , Shailendra Verma , linux-kernel@vger.kernel.org, vidushi.koul@samsung.com, hillf.zj@alibaba-inc.com Subject: Re: [PATCH] arch:arm:mm:Correction in the boundary check for module end address. Message-ID: <20151109160137.GA8644@n2100.arm.linux.org.uk> References: <1447055848-28180-1-git-send-email-shailendra.v@samung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2773 Lines: 76 On Tue, Nov 10, 2015 at 12:35:50AM +0900, Jungseung Lee wrote: > Hi, > > 2015-11-09 16:57 GMT+09:00 Shailendra Verma : > > From: Shailendra Verma > > > > The module end boundary check is not proper.The out of bound value > > of module end can produce undesired results. > > > > Signed-off-by: Shailendra Verma > > Reviewed-by: Ravikant Bijendra Sharma > > --- > > linux-4.3-rc6/arch/arm/mm/pageattr.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/linux-4.3-rc6/arch/arm/mm/pageattr.c b/linux-4.3-rc6/arch/arm/mm/pageattr.c > > index cf30daf..be7fe4b 100644 > > --- a/linux-4.3-rc6/arch/arm/mm/pageattr.c > > +++ b/linux-4.3-rc6/arch/arm/mm/pageattr.c > > @@ -52,7 +52,7 @@ static int change_memory_common(unsigned long addr, int numpages, > > if (start < MODULES_VADDR || start >= MODULES_END) > > return -EINVAL; > > > > - if (end < MODULES_VADDR || start >= MODULES_END) > > + if (end < MODULES_VADDR || end >= MODULES_END) > > return -EINVAL; > > > > data.set_mask = set_mask; > > -- > > 1.7.9.5 > > > Same patch with proper format is already submitted by Hillf. > https://lkml.org/lkml/2015/5/3/202 What happened to that patch? It should at least have had a: Fixes: f2ca09f381a5 ("ARM: 8311/1: Don't use is_module_addr in setting page attributes") tag on it, and it needs to find its way into the patch system. As no one has reported a crash (I don't think it's crash-causing, but is merely a correctness issue) I don't see any reason to backport it to stable trees. Other changes are needed here as well - the original commit creating this contains: + if (!IS_ALIGNED(addr, PAGE_SIZE)) { + start &= PAGE_MASK; + end = start + size; + WARN_ON_ONCE(1); + } which is truely amazing. Fine, it may not be intended to work with non-aligned addresses, but if we're going to round the start down, then rounding the end down as well like that is also buggy. unsigned long start = addr; unsigned long size = PAGE_SIZE * numpages; unsigned long end = start + size; if (WARN_ON_ONCE(!IS_ALIGNED(addr, PAGE_SIZE)) { start &= PAGE_MASK; end = PAGE_ALIGN(end); } would be much better - this will round 'end' up, so we encompass the entire requested region. -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/