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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 99E3CC433F5 for ; Wed, 19 Jan 2022 13:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:To:Subject:MIME-Version: Date:Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=JAmfLY8JJgK7nfhikpOlaN5vdPioAa44Qq/3My7hAO8=; b=DxNECcuT/GPg+kR7+4tLUXZZhU YWD73PrBe9OsGjfHVbSg0v/VgznU6peR1+A32RJ/EQT0LFuCtZYO213pD7H7M0TMLwJslGkLVdS/V MMywSZTwsvfh8bknEKuV2lvogNcHXb1Fm7fArxpvs7lCfCbcxPLWvvGDnGxAFXymoEXFMXibQdGbW XmeHMzCjNCn3oTeIjlSwulIz0YsCCiNkkUEun92II5//W2yZDtTQC4tFxZpCJ0Svw4b4qS1vU8wki Vaj3bSL+EkJq2IuTaQky5qJfqwu/AdxUy48b9QKajzQtiTWFecAqRDYzjZUodA3flevegh+BtzrNf HM884LHQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAB0l-005cNC-RN; Wed, 19 Jan 2022 13:28:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAB0i-005cLJ-1m for linux-arm-kernel@lists.infradead.org; Wed, 19 Jan 2022 13:28:25 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 00E38ED1; Wed, 19 Jan 2022 05:28:21 -0800 (PST) Received: from [10.57.67.190] (unknown [10.57.67.190]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1F94E3F73D; Wed, 19 Jan 2022 05:28:18 -0800 (PST) Message-ID: Date: Wed, 19 Jan 2022 13:28:14 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] vmap(): don't allow invalid pages Content-Language: en-GB To: Yury Norov , Catalin Marinas , Will Deacon , Andrew Morton , Nicholas Piggin , Ding Tianhong , Anshuman Khandual , Matthew Wilcox , Alexey Klimov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220118235244.540103-1-yury.norov@gmail.com> From: Robin Murphy In-Reply-To: <20220118235244.540103-1-yury.norov@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220119_052824_184941_FE00AB45 X-CRM114-Status: GOOD ( 19.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2022-01-18 23:52, Yury Norov wrote: > vmap() takes struct page *pages as one of arguments, and user may provide > an invalid pointer which would lead to DABT at address translation later. > > Currently, kernel checks the pages against NULL. In my case, however, the > address was not NULL, and was big enough so that the hardware generated > Address Size Abort on arm64. > > Interestingly, this abort happens even if copy_from_kernel_nofault() is > used, which is quite inconvenient for debugging purposes. > > This patch adds a pfn_valid() check into vmap() path, so that invalid > mapping will not be created. > > RFC: https://lkml.org/lkml/2022/1/18/815 > v1: use pfn_valid() instead of adding an arch-specific > arch_vmap_page_valid(). Thanks to Matthew Wilcox for the hint. > > Signed-off-by: Yury Norov > --- > mm/vmalloc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d2a00ad4e1dd..a4134ee56b10 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -477,6 +477,8 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr, > return -EBUSY; > if (WARN_ON(!page)) > return -ENOMEM; > + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) Is it page_to_pfn() guaranteed to work without blowing up if page is invalid in the first place? Looking at the CONFIG_SPARSEMEM case I'm not sure that's true... Robin. > + return -EINVAL; > set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); > (*nr)++; > } while (pte++, addr += PAGE_SIZE, addr != end); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel