From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11024C433F5 for ; Wed, 6 Oct 2021 14:09:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7FA83610A5 for ; Wed, 6 Oct 2021 14:09:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7FA83610A5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D48786B006C; Wed, 6 Oct 2021 10:09:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CF8A96B0071; Wed, 6 Oct 2021 10:09:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BE7A76B0073; Wed, 6 Oct 2021 10:09:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0021.hostedemail.com [216.40.44.21]) by kanga.kvack.org (Postfix) with ESMTP id AE9AF6B006C for ; Wed, 6 Oct 2021 10:09:57 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 48278181F10E6 for ; Wed, 6 Oct 2021 14:09:57 +0000 (UTC) X-FDA: 78666196434.34.A61AC57 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf16.hostedemail.com (Postfix) with ESMTP id E2DB6F001CE2 for ; Wed, 6 Oct 2021 14:09:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=PhgxCECS6IONaJckvI2zU/uNP0Cin8hVUxtpeDZAfbA=; b=P9lilLJRjkXJFKSUM+YLnu5maM odChp9GFBCZh8BloKEkvGChAquvP/0KFtciz3CjQ/Yum/WEk4Ts+doS1ErAPRNvKe4228+x/nZFHp N/0o305IUXSJWF8YJi56SMGTWZQ5+MKpmb0upADUAgMO6iZJBttbkJJVnohVVPHhem/Kkl7pKkNaM Trbir55v0OcfCumgGtoRkv8yAYESd+UDL1eLvZyxZ6ZJawvBZxQmp7cLwZB65fbZ7xteKYkUYA46M Mgf80U0WGzuo4Etsj6T5r2ND4BA0X3cFzSo0cu56b5K+Jo6y7tRYWuzkHurnsEzS+f1NpHJ3k+J+1 3lFFPrrA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mY7bC-000xih-H5; Wed, 06 Oct 2021 14:09:07 +0000 Date: Wed, 6 Oct 2021 15:08:46 +0100 From: Matthew Wilcox To: Kees Cook Cc: linux-mm@kvack.org, Thomas Gleixner Subject: Re: [PATCH v2 3/3] mm/usercopy: Detect compound page overruns Message-ID: References: <20211006124226.209484-1-willy@infradead.org> <20211006124226.209484-4-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211006124226.209484-4-willy@infradead.org> Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=P9lilLJR; spf=none (imf16.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E2DB6F001CE2 X-Stat-Signature: 61ha7uba9exhu85mde9496gogna7zg1o X-HE-Tag: 1633529395-446056 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Oct 06, 2021 at 01:42:26PM +0100, Matthew Wilcox (Oracle) wrote: > Move the compound page overrun detection out of > CONFIG_HARDENED_USERCOPY_PAGESPAN so it's enabled for more people. > > Signed-off-by: Matthew Wilcox (Oracle) > Acked-by: Kees Cook > --- > mm/usercopy.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/mm/usercopy.c b/mm/usercopy.c > index 63476e1506e0..b825c4344917 100644 > --- a/mm/usercopy.c > +++ b/mm/usercopy.c > @@ -194,11 +194,6 @@ static inline void check_page_span(const void *ptr, unsigned long n, > ((unsigned long)end & (unsigned long)PAGE_MASK))) > return; > > - /* Allow if fully inside the same compound (__GFP_COMP) page. */ > - endpage = virt_to_head_page(end); > - if (likely(endpage == page)) > - return; > - > /* > * Reject if range is entirely either Reserved (i.e. special or > * device memory), or CMA. Otherwise, reject since the object spans Needs an extra hunk to avoid a warning with that config: @@ -163,7 +163,6 @@ static inline void check_page_span(const void *ptr, unsigned long n, { #ifdef CONFIG_HARDENED_USERCOPY_PAGESPAN const void *end = ptr + n - 1; - struct page *endpage; bool is_reserved, is_cma; /* I'll wait a few days and send a v3.