From nobody Tue Jun 30 01:43:45 2026 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 AEE3FC433F5 for ; Fri, 28 Jan 2022 09:03:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236217AbiA1JDb (ORCPT ); Fri, 28 Jan 2022 04:03:31 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:31250 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235560AbiA1JD2 (ORCPT ); Fri, 28 Jan 2022 04:03:28 -0500 Received: from dggeme752-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JlWgb0MQpzbkCc; Fri, 28 Jan 2022 17:02:35 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggeme752-chm.china.huawei.com (10.3.19.98) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.21; Fri, 28 Jan 2022 17:03:26 +0800 From: h00486469 To: , , , , CC: , Subject: [PATCH] arm64: fix slab-out-of-bounds in emulation_proc_handler when accessing concurrently Date: Fri, 28 Jan 2022 17:03:24 +0800 Message-ID: <20220128090324.2727688-1-hewenliang4@huawei.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggeme752-chm.china.huawei.com (10.3.19.98) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: hewenliang SAN reports an issue of slab-out-of-bounds in emulation_proc_handler when we try to read/write the interfaces in /proc/sys/abi concurrently. So we need to add emulation_proc_lock to protect table->data and insn from data corruption in emulation_proc_handler. The stack is follows: Call trace: dump_backtrace+0x0/0x310 show_stack+0x28/0x38 dump_stack+0xec/0x15c print_address_description+0x68/0x2d0 kasan_report+0x130/0x2f0 __asan_load4+0x88/0xb0 emulation_proc_handler+0x58/0x158 proc_sys_call_handler+0x1dc/0x228 proc_sys_read+0x44/0x58 __vfs_read+0xe0/0x320 vfs_read+0xbc/0x1c0 __arm64_sys_read+0x50/0x60 el0_svc_common+0xc8/0x2b8 el0_svc_handler+0xf8/0x160 el0_svc+0x10/0x218 Allocated by task 1: kasan_kmalloc+0xe0/0x190 kmem_cache_alloc_trace+0x18c/0x418 register_insn_emulation+0x4c/0x2b0 armv8_deprecated_init+0x40/0x108 do_one_initcall+0xb4/0x508 kernel_init_freeable+0x7d0/0x8e0 kernel_init+0x20/0x1a8 ret_from_fork+0x10/0x18 Mmeory state around the buggy address: >ffff8026dacf0b00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc Fixes: 587064b610c7 ("arm64: Add framework for legacy instruction emulation= ") Signed-off-by: hewenliang Signed-off-by: hejingxian Signed-off-by: fulin --- arch/arm64/kernel/armv8_deprecated.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8= _deprecated.c index 6875a16b09d2..d2ac483b0dd8 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -59,6 +59,7 @@ struct insn_emulation { static LIST_HEAD(insn_emulation); static int nr_insn_emulated __initdata; static DEFINE_RAW_SPINLOCK(insn_emulation_lock); +static DEFINE_MUTEX(emulation_proc_lock); =20 static void register_emulation_hooks(struct insn_emulation_ops *ops) { @@ -207,9 +208,12 @@ static int emulation_proc_handler(struct ctl_table *ta= ble, int write, loff_t *ppos) { int ret =3D 0; - struct insn_emulation *insn =3D (struct insn_emulation *) table->data; - enum insn_emulation_mode prev_mode =3D insn->current_mode; + struct insn_emulation *insn; + enum insn_emulation_mode prev_mode; =20 + mutex_lock(&emulation_proc_lock); + insn =3D (struct insn_emulation *) table->data; + prev_mode =3D insn->current_mode; table->data =3D &insn->current_mode; ret =3D proc_dointvec_minmax(table, write, buffer, lenp, ppos); =20 @@ -224,6 +228,7 @@ static int emulation_proc_handler(struct ctl_table *tab= le, int write, } ret: table->data =3D insn; + mutex_unlock(&emulation_proc_lock); return ret; } =20 --=20 2.27.0