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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 2DB94C31E5B for ; Wed, 19 Jun 2019 02:28:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0990C20863 for ; Wed, 19 Jun 2019 02:28:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729809AbfFSC21 (ORCPT ); Tue, 18 Jun 2019 22:28:27 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:18641 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726037AbfFSC21 (ORCPT ); Tue, 18 Jun 2019 22:28:27 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 3A7EADD21782C038FB53; Wed, 19 Jun 2019 10:28:24 +0800 (CST) Received: from [127.0.0.1] (10.133.205.80) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.439.0; Wed, 19 Jun 2019 10:28:17 +0800 Subject: Re: [PATCH] modules: fix BUG when load module with rodata=n To: Jessica Yu References: <1560754797-40683-1-git-send-email-yangyingliang@huawei.com> <20190618134839.GA31349@linux-8ccs> CC: , , , From: Yang Yingliang Message-ID: <5D099DC0.60609@huawei.com> Date: Wed, 19 Jun 2019 10:28:16 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20190618134839.GA31349@linux-8ccs> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.133.205.80] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > > Thanks! > > Jessica > > > . >