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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07C1FC433F5 for ; Sat, 8 Jan 2022 11:58:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231714AbiAHL6J (ORCPT ); Sat, 8 Jan 2022 06:58:09 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:31149 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229675AbiAHL6I (ORCPT ); Sat, 8 Jan 2022 06:58:08 -0500 Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4JWJSH4svmz8wBq; Sat, 8 Jan 2022 19:55:27 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Sat, 8 Jan 2022 19:58:06 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.20; Sat, 8 Jan 2022 19:58:05 +0800 Message-ID: <09ed46a5-6df3-ffc0-8243-61612c06153a@huawei.com> Date: Sat, 8 Jan 2022 19:58:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v2 1/2] powerpc: Fix virt_addr_valid() check Content-Language: en-US To: Kees Cook , Laura Abbott , "Mark Rutland" , , Andrew Morton , , Michael Ellerman , Benjamin Herrenschmidt , "Paul Mackerras" , CC: Nicholas Piggin References: <20211225120621.13908-1-wangkefeng.wang@huawei.com> <20211225120621.13908-2-wangkefeng.wang@huawei.com> From: Kefeng Wang In-Reply-To: <20211225120621.13908-2-wangkefeng.wang@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggeme704-chm.china.huawei.com (10.1.199.100) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi PPC maintainers， ping.. On 2021/12/25 20:06, Kefeng Wang wrote: > When run ethtool eth0, the BUG occurred, > > usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)! > kernel BUG at mm/usercopy.c:99 > ... > usercopy_abort+0x64/0xa0 (unreliable) > __check_heap_object+0x168/0x190 > __check_object_size+0x1a0/0x200 > dev_ethtool+0x2494/0x2b20 > dev_ioctl+0x5d0/0x770 > sock_do_ioctl+0xf0/0x1d0 > sock_ioctl+0x3ec/0x5a0 > __se_sys_ioctl+0xf0/0x160 > system_call_exception+0xfc/0x1f0 > system_call_common+0xf8/0x200 > > The code shows below, > > data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN)); > copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN)) > > The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true > on PowerPC64, which leads to the panic. > > As commit 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va > and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in > the virt_addr_valid(). > > Signed-off-by: Kefeng Wang > --- > arch/powerpc/include/asm/page.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h > index 254687258f42..300d4c105a3a 100644 > --- a/arch/powerpc/include/asm/page.h > +++ b/arch/powerpc/include/asm/page.h > @@ -132,7 +132,10 @@ static inline bool pfn_valid(unsigned long pfn) > #define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr)) > #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) > > -#define virt_addr_valid(kaddr) pfn_valid(virt_to_pfn(kaddr)) > +#define virt_addr_valid(vaddr) ({ \ > + unsigned long _addr = (unsigned long)vaddr; \ > + (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \ > +}) > > /* > * On Book-E parts we need __va to parse the device tree and we can't