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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 51259C636CA for ; Mon, 19 Jul 2021 03:10:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C63D6108B for ; Mon, 19 Jul 2021 03:10:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233964AbhGSDNA (ORCPT ); Sun, 18 Jul 2021 23:13:00 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:15038 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233759AbhGSDMd (ORCPT ); Sun, 18 Jul 2021 23:12:33 -0400 Received: from dggeme765-chm.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4GSmvR65mfzZqkK; Mon, 19 Jul 2021 11:06:11 +0800 (CST) Received: from DESKTOP-E0KHRBE.china.huawei.com (10.67.103.82) by dggeme765-chm.china.huawei.com (10.3.19.111) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 19 Jul 2021 11:09:32 +0800 From: Shaobo Huang To: CC: , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH] ARM: fix panic when kasan and kprobe are enabled Date: Mon, 19 Jul 2021 11:09:32 +0800 Message-ID: <20210719030932.23384-1-huangshaobo6@huawei.com> X-Mailer: git-send-email 2.21.0.windows.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.67.103.82] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggeme765-chm.china.huawei.com (10.3.19.111) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 17 Jul 2021 at 01:01, Ard Biesheuvel wrote: > On Wed, 14 Jul 2021 at 10:27, Shaobo Huang wrote: >> >> From: huangshaobo >> >> arm32 uses software to simulate the instruction replaced >> by kprobe. some instructions may be simulated by constructing >> assembly functions. therefore, before executing instruction >> simulation, it is necessary to construct assembly function >> execution environment in C language through binding registers. >> after kasan is enabled, the register binding relationship will >> be destroyed, resulting in instruction simulation errors and >> causing kernel panic. >> >> the kprobe emulate instruction function is distributed in three >> files: actions-common.c actions-arm.c actions-thumb.c, so disable >> KASAN when compiling these files. >> >> for example, use kprobe insert on cap_capable+20 after kasan >> enabled, the cap_capable assembly code is as follows: >> : >> e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr} >> e1a05000 mov r5, r0 >> e280006c add r0, r0, #108 ; 0x6c >> e1a04001 mov r4, r1 >> e1a06002 mov r6, r2 >> e59fa090 ldr sl, [pc, #144] ; >> ebfc7bf8 bl c03aa4b4 <__asan_load4> >> e595706c ldr r7, [r5, #108] ; 0x6c >> e2859014 add r9, r5, #20 >> ...... >> The emulate_ldr assembly code after enabling kasan is as follows: >> c06f1384 : >> e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr} >> e282803c add r8, r2, #60 ; 0x3c >> e1a05000 mov r5, r0 >> e7e37855 ubfx r7, r5, #16, #4 >> e1a00008 mov r0, r8 >> e1a09001 mov r9, r1 >> e1a04002 mov r4, r2 >> ebf35462 bl c03c6530 <__asan_load4> >> e357000f cmp r7, #15 >> e7e36655 ubfx r6, r5, #12, #4 >> e205a00f and sl, r5, #15 >> 0a000001 beq c06f13bc >> e0840107 add r0, r4, r7, lsl #2 >> ebf3545c bl c03c6530 <__asan_load4> >> e084010a add r0, r4, sl, lsl #2 >> ebf3545a bl c03c6530 <__asan_load4> >> e2890010 add r0, r9, #16 >> ebf35458 bl c03c6530 <__asan_load4> >> e5990010 ldr r0, [r9, #16] >> e12fff30 blx r0 >> e356000f cm r6, #15 >> 1a000014 bne c06f1430 >> e1a06000 mov r6, r0 >> e2840040 add r0, r4, #64 ; 0x40 >> ...... >> >> when running in emulate_ldr to simulate the ldr instruction, panic >> occurred, and the log is as follows: >> Unable to handle kernel NULL pointer dereference at virtual address >> 00000090 >> pgd = ecb46400 >> [00000090] *pgd=2e0fa003, *pmd=00000000 >> Internal error: Oops: 206 [#1] SMP ARM >> PC is at cap_capable+0x14/0xb0 >> LR is at emulate_ldr+0x50/0xc0 >> psr: 600d0293 sp : ecd63af8 ip : 00000004 fp : c0a7c30c >> r10: 00000000 r9 : c30897f4 r8 : ecd63cd4 >> r7 : 0000000f r6 : 0000000a r5 : e59fa090 r4 : ecd63c98 >> r3 : c06ae294 r2 : 00000000 r1 : b7611300 r0 : bf4ec008 >> Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user >> Control: 32c5387d Table: 2d546400 DAC: 55555555 >> Process bash (pid: 1643, stack limit = 0xecd60190) >> (cap_capable) from (kprobe_handler+0x218/0x340) >> (kprobe_handler) from (kprobe_trap_handler+0x24/0x48) >> (kprobe_trap_handler) from (do_undefinstr+0x13c/0x364) >> (do_undefinstr) from (__und_svc_finish+0x0/0x30) >> (__und_svc_finish) from (cap_capable+0x18/0xb0) >> (cap_capable) from (cap_vm_enough_memory+0x38/0x48) >> (cap_vm_enough_memory) from >> (security_vm_enough_memory_mm+0x48/0x6c) >> (security_vm_enough_memory_mm) from >> (copy_process.constprop.5+0x16b4/0x25c8) >> (copy_process.constprop.5) from (_do_fork+0xe8/0x55c) >> (_do_fork) from (SyS_clone+0x1c/0x24) >> (SyS_clone) from (__sys_trace_return+0x0/0x10) >> Code: 0050a0e1 6c0080e2 0140a0e1 0260a0e1 (f801f0e7) >> >> Fixes: 35aa1df43283 ("ARM kprobes: instruction single-stepping support") >> Fixes: 421015713b30 ("ARM: 9017/2: Enable KASan for ARM") >> Signed-off-by: huangshaobo >> Asked-by: Ard Biesheuvel > > Please don't do this - the maintainer will pick it up when applying, > or when you send a new version of the patch, it is OK to add these > tags if you have not made any substantial changes. > > But please do *not* add tags like this on someone else's behalf by > replying to the email - and I should also point out that 'asked-by' is > bogus. > Hi ardb, 1.The original patch you have been asked-by by email before, link: https://lore.kernel.org/linux-arm-kernel/CAMj1kXGqfF68MT4WwrxS0cYiUBb0gODDh-wGZSQcW9vxdfK90A@mail.gmail.com/ 2.In addition to adding the asked-by tag, there is no other content modification in this patch 3.The patch was reissued because the previous recipient did not include kasan maintainer and reviewers thanks, ShaoBo Huang > >> --- >> arch/arm/probes/kprobes/Makefile | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile >> index 14db56f49f0a..6159010dac4a 100644 >> --- a/arch/arm/probes/kprobes/Makefile >> +++ b/arch/arm/probes/kprobes/Makefile >> @@ -1,4 +1,7 @@ >> # SPDX-License-Identifier: GPL-2.0 >> +KASAN_SANITIZE_actions-common.o := n >> +KASAN_SANITIZE_actions-arm.o := n >> +KASAN_SANITIZE_actions-thumb.o := n >> obj-$(CONFIG_KPROBES) += core.o actions-common.o checkers-common.o >> obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o >> test-kprobes-objs := test-core.o >> -- >> 2.12.3 >>