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 492C4C433F5 for ; Thu, 27 Jan 2022 12:22:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241050AbiA0MWO (ORCPT ); Thu, 27 Jan 2022 07:22:14 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:30315 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235916AbiA0MWN (ORCPT ); Thu, 27 Jan 2022 07:22:13 -0500 Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Jl07N53Hkzbjh3; Thu, 27 Jan 2022 20:21:20 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Thu, 27 Jan 2022 20:22:11 +0800 Received: from localhost.localdomain.localdomain (10.175.113.25) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Thu, 27 Jan 2022 20:22:11 +0800 From: Kefeng Wang To: , , , , CC: , , , , Kefeng Wang Subject: [PATCH v3] powerpc: Fix virt_addr_valid() check Date: Thu, 27 Jan 2022 20:37:54 +0800 Message-ID: <20220127123754.77825-1-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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 When run ethtool eth0 on PowerPC64, 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, let's check the virt addr above PAGE_OFFSET in the virt_addr_valid() for PowerPC64, which will make sure that the passed address is a valid linear map address. Meanwhile, PAGE_OFFSET is the virtual address of the start of lowmem, the check is suitable for PowerPC32 too. Signed-off-by: Kefeng Wang --- v3: - update changelog and remove a redundant cast 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..a8a29a23ce2d 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; \ + _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 -- 2.26.2