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 X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60D8FC31E49 for ; Wed, 19 Jun 2019 10:04:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34DBF214AF for ; Wed, 19 Jun 2019 10:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560938646; bh=UCNKY/b1BHiW4G5pqFqxcfsfN7ElJmk75D57kT4CuMQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=GjePwjlCiltkdlWgJPFGxnnp3dH67jdf4gFYuPZp/fpoaZpPu75JVJfX60o2qkrCV aUVymMq5B9wfEoE5X/+ZQQZvjUsDgPAovVxC3SWeedplVcqCh/gV5I2cRbYJLQ8o5Z 3bJwaiveWaea2PjHTfe9LiM4KeKX/TJXNnB1hkLc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731385AbfFSKEE (ORCPT ); Wed, 19 Jun 2019 06:04:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:41610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbfFSKEE (ORCPT ); Wed, 19 Jun 2019 06:04:04 -0400 Received: from linux-8ccs (ip5f5adbc1.dynamic.kabel-deutschland.de [95.90.219.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EB86520B1F; Wed, 19 Jun 2019 10:04:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560938643; bh=UCNKY/b1BHiW4G5pqFqxcfsfN7ElJmk75D57kT4CuMQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kuGO5xg+wCmOCCzA9iooqHYkNt2FOhJf/ly8pJM7Aqq3Bo7aPwH3VrDckAaZfTrxb tQPNaVXcEi4vjGpVfx5oo+y6r9X/7p1yBCUI8GDqHxkB+Gbw4W6bpXnCY+20OtmSzp ddCxXex5QHuh95TPX8czJbqLpWIi5Y9xIMftM/ok= Date: Wed, 19 Jun 2019 12:03:58 +0200 From: Jessica Yu To: Yang Yingliang Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, namit@vmware.com, cj.chengjian@huawei.com Subject: Re: [PATCH] modules: fix BUG when load module with rodata=n Message-ID: <20190619100358.GA11478@linux-8ccs> References: <1560754797-40683-1-git-send-email-yangyingliang@huawei.com> <20190618134839.GA31349@linux-8ccs> <5D099DC0.60609@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5D099DC0.60609@huawei.com> X-OS: Linux linux-8ccs 5.1.0-rc1-lp150.12.28-default+ x86_64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +++ Yang Yingliang [19/06/19 10:28 +0800]: > > >On 2019/6/18 21:48, Jessica Yu wrote: >>+++ Yang Yingliang [17/06/19 14:59 +0800]: >>>When loading a module with rodata=n, it causes an executing >>>NX-protected page BUG. >>> >>>[ 32.379191] kernel tried to execute NX-protected page - exploit >>>attempt? (uid: 0) >>>[ 32.382917] BUG: unable to handle page fault for address: >>>ffffffffc0005000 >>>[ 32.385947] #PF: supervisor instruction fetch in kernel mode >>>[ 32.387662] #PF: error_code(0x0011) - permissions violation >>>[ 32.389352] PGD 240c067 P4D 240c067 PUD 240e067 PMD 421a52067 >>>PTE 8000000421a53063 >>>[ 32.391396] Oops: 0011 [#1] SMP PTI >>>[ 32.392478] CPU: 7 PID: 2697 Comm: insmod Tainted: G >>>O 5.2.0-rc5+ #202 >>>[ 32.394588] Hardware name: QEMU Standard PC (i440FX + PIIX, >>>1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org >>>04/01/2014 >>>[ 32.398157] RIP: 0010:ko_test_init+0x0/0x1000 [ko_test] >>>[ 32.399662] Code: Bad RIP value. >>>[ 32.400621] RSP: 0018:ffffc900029f3ca8 EFLAGS: 00010246 >>>[ 32.402171] RAX: 0000000000000000 RBX: 0000000000000000 RCX: >>>0000000000000000 >>>[ 32.404332] RDX: 00000000000004c7 RSI: 0000000000000cc0 RDI: >>>ffffffffc0005000 >>>[ 32.406347] RBP: ffffffffc0005000 R08: ffff88842fbebc40 R09: >>>ffffffff810ede4a >>>[ 32.408392] R10: ffffea00108e3480 R11: 0000000000000000 R12: >>>ffff88842bee21a0 >>>[ 32.410472] R13: 0000000000000001 R14: 0000000000000001 R15: >>>ffffc900029f3e78 >>>[ 32.412609] FS: 00007fb4f0c0a700(0000) >>>GS:ffff88842fbc0000(0000) knlGS:0000000000000000 >>>[ 32.414722] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>[ 32.416290] CR2: ffffffffc0004fd6 CR3: 0000000421a90004 CR4: >>>0000000000020ee0 >>>[ 32.418471] Call Trace: >>>[ 32.419136] do_one_initcall+0x41/0x1df >>>[ 32.420199] ? _cond_resched+0x10/0x40 >>>[ 32.421433] ? kmem_cache_alloc_trace+0x36/0x160 >>>[ 32.422827] do_init_module+0x56/0x1f7 >>>[ 32.423946] load_module+0x1e67/0x2580 >>>[ 32.424947] ? __alloc_pages_nodemask+0x150/0x2c0 >>>[ 32.426413] ? map_vm_area+0x2d/0x40 >>>[ 32.427530] ? __vmalloc_node_range+0x1ef/0x260 >>>[ 32.428850] ? __do_sys_init_module+0x135/0x170 >>>[ 32.430060] ? _cond_resched+0x10/0x40 >>>[ 32.431249] __do_sys_init_module+0x135/0x170 >>>[ 32.432547] do_syscall_64+0x43/0x120 >>>[ 32.433853] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>> >>>Because if rodata=n, set_memory_x() cann't be called, fix this by >>>calling set_memory_x in complete_formation(); >>> >>>Fixes: f2c65fb3221a ("x86/modules: Avoid breaking W^X while >>>loading modules") >>>Suggested-by: Jian Cheng >>>Signed-off-by: Yang Yingliang >>>--- >>>kernel/module.c | 9 +++++++-- >>>1 file changed, 7 insertions(+), 2 deletions(-) >>> >>>diff --git a/kernel/module.c b/kernel/module.c >>>index 80c7c09584cf..1a5d879573c3 100644 >>>--- a/kernel/module.c >>>+++ b/kernel/module.c >>>@@ -1949,12 +1949,10 @@ void module_enable_ro(const struct module >>>*mod, bool after_init) >>> set_vm_flush_reset_perms(mod->core_layout.base); >>> set_vm_flush_reset_perms(mod->init_layout.base); >>> frob_text(&mod->core_layout, set_memory_ro); >>>- frob_text(&mod->core_layout, set_memory_x); >>> >>> frob_rodata(&mod->core_layout, set_memory_ro); >>> >>> frob_text(&mod->init_layout, set_memory_ro); >>>- frob_text(&mod->init_layout, set_memory_x); >>> >>> frob_rodata(&mod->init_layout, set_memory_ro); >> >>Just a style-related nit: could you also please shrink down this chunk >>and remove the empty lines between the frob_* calls? >OK，I will do it in next version. > >> >>>@@ -2018,6 +2016,12 @@ void set_all_modules_text_ro(void) >>>static void module_enable_nx(const struct module *mod) { } >>>#endif >> >>And note that we will need a stub for module_enable_x() here as well. >module_enable_x() is outside of CONFIG_STRICT_MODULE_RWX. Ah yeah you're right, my mistake. We need it outside of the CONFIG_STRICT_MODULE_RWX block anyway since module_alloc() on x86 allocates memory with PAGE_KERNEL now instead of PAGE_KERNEL_EXEC and we need to set text to executable regardless.