From patchwork Mon Oct 4 22:42:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12535083 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 C425DC433EF for ; Mon, 4 Oct 2021 22:46:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 70BB461506 for ; Mon, 4 Oct 2021 22:46:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 70BB461506 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 11558940074; Mon, 4 Oct 2021 18:46:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 09F5C94000B; Mon, 4 Oct 2021 18:46:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E5B5F940074; Mon, 4 Oct 2021 18:46:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id D210694000B for ; Mon, 4 Oct 2021 18:46:08 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 99E2B2CBBA for ; Mon, 4 Oct 2021 22:46:08 +0000 (UTC) X-FDA: 78660239616.25.BFC8B4A Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf22.hostedemail.com (Postfix) with ESMTP id 5CA9E31C3 for ; Mon, 4 Oct 2021 22:46:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=CxZ+S2dey61N1rPAOujjNfz8KYhMeyKgJQ6ggvHKlMo=; b=fomvCjU55/qmfkO73k1xtXLYqh LcyVarpBpx5mtV4h/stihEmLzuIJ6ZK1KNLTugJL7Wc3SbWyV4gFUGy3zPR2ayLOabt/GfbZbpR1C bY24mqTUfMMGAWN4w76qk1I80CTy29PlzoFXjknJTbRhQDMPu8gp3cnLfGqPda3N6RLkjqGfYgRKY kRBOMaTlS1knv/+MSs1z7rO4B+//7zND0NkkSMW51ogQwxCd+QOI8UtmIFXCb7RA7gVf/9n+nfibK O7GM7cXVryU8Psw+Stn8oameeEIrIUnRuv4a9WXtccK+FdIs4di9nXROtn/XadyQF7teT9l3JKk2k ABtkoWMg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mXWhQ-00HMXA-Ao; Mon, 04 Oct 2021 22:44:53 +0000 From: "Matthew Wilcox (Oracle)" To: Kees Cook Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, Thomas Gleixner Subject: [PATCH 3/3] mm/usercopy: Detect compound page overruns Date: Mon, 4 Oct 2021 23:42:23 +0100 Message-Id: <20211004224224.4137992-4-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211004224224.4137992-1-willy@infradead.org> References: <20211004224224.4137992-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 5CA9E31C3 X-Stat-Signature: b3tr9xqna3wn44ng9ymkctf8b35yufeg Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=fomvCjU5; dmarc=none; spf=none (imf22.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-HE-Tag: 1633387568-734676 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: 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 | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/usercopy.c b/mm/usercopy.c index 7bfc4f9ed1e4..e395462961d5 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 @@ -250,6 +245,10 @@ static inline void check_heap_object(const void *ptr, unsigned long n, if (PageSlab(page)) { /* Check slab allocator for flags and size. */ __check_heap_object(ptr, n, page, to_user); + } else if (PageHead(page)) { + /* A compound allocation */ + if (ptr + n > page_address(page) + page_size(page)) + usercopy_abort("page alloc", NULL, to_user, 0, n); } else { /* Verify object does not incorrectly span multiple pages. */ check_page_span(ptr, n, page, to_user);