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 EFB88C433EF for ; Mon, 31 Jan 2022 12:21:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241177AbiAaMVH (ORCPT ); Mon, 31 Jan 2022 07:21:07 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:50038 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241160AbiAaMVH (ORCPT ); Mon, 31 Jan 2022 07:21:07 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7EB2BB82A9B; Mon, 31 Jan 2022 12:21:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF75CC340E8; Mon, 31 Jan 2022 12:21:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643631665; bh=oHQ4YRY3ehIhnhLHdxJZy6siAb+6oN6CU0NTtAxQkZQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YlH0A/uvlUBny61d5HYG5iYVjYO+2+uWWJ5BCZFXQFgP9p6ZJCQb7HGROXGHSzlTi 1+7x2wQIQXQI4kHJQ4L+nxbW3pYq3poY+ws+6RRSxSl+gL2rHF+KWGghUvIQ8N/4m3 8pMG0T+y9SVZvIbyavFKufZM1bweyLnANfT2V9Ds= Date: Mon, 31 Jan 2022 13:21:02 +0100 From: Greg Kroah-Hartman To: Ard Biesheuvel Cc: Linux Kernel Mailing List , "# 3.4.x" , huangshaobo , "Russell King (Oracle)" Subject: Re: [PATCH 5.4 33/64] ARM: 9170/1: fix panic when kasan and kprobe are enabled Message-ID: References: <20220131105215.644174521@linuxfoundation.org> <20220131105216.796938973@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jan 31, 2022 at 01:14:28PM +0100, Ard Biesheuvel wrote: > On Mon, 31 Jan 2022 at 11:59, Greg Kroah-Hartman > wrote: > > > > From: sparkhuang > > > > commit 8b59b0a53c840921b625378f137e88adfa87647e upstream. > > > > 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 > > Acked-by: Ard Biesheuvel > > Signed-off-by: Russell King (Oracle) > > Signed-off-by: Greg Kroah-Hartman > > Probably a bit late to mention this but v5.4 does not support KASAN on > ARM, so this patch is fairly pointless. Hah, it came in in 5.11, so I can drop this from anything older than that. Thanks for catching this, I missed it. greg k-h