From patchwork Tue Aug 13 06:09:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Knut Omang X-Patchwork-Id: 11091143 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E7E2B746 for ; Tue, 13 Aug 2019 06:11:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D7D3E28438 for ; Tue, 13 Aug 2019 06:11:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CAB02284CE; Tue, 13 Aug 2019 06:11:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 50EE728438 for ; Tue, 13 Aug 2019 06:11:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727616AbfHMGLc (ORCPT ); Tue, 13 Aug 2019 02:11:32 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:37120 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727614AbfHMGLb (ORCPT ); Tue, 13 Aug 2019 02:11:31 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7D68wnv022022; Tue, 13 Aug 2019 06:11:11 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2019-08-05; bh=Xgef0XFFFPz0RPMRvPeUpqgM+lNFsR5792wofX4MhfM=; b=QTBRw1J8EwzFKxTiUFmLQgNu5gJSIlHqxIXINo/GKFDy5+tNbI6IEjURZfo8AowNa2RE HRbAaqZ3IYt5aDtt8KrnQa56YdCAoa+U49qwVSN8n0bSTuFfvXX7Y4DsSvTCR5Cpk4/h QW8xlED9BzhsCmcmoD4sny1+qHo8meLw4/wvHZvHdZ5fdwneMqAJ6ZjLSQ2GcWJCnpKz Bs1ZQOHbykMMpo+/94Mrav4hM7xrrhKy8Oqgloat9Bc3tGiTHL2WrqaqV93a61puONki 3C6OFymR8D7IcthR2aE/6Sb7TZAzwTm7hgQAPry4VsOOY3jZ4UfCCITlQwgzJjtA0ZzW ow== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2018-07-02; bh=Xgef0XFFFPz0RPMRvPeUpqgM+lNFsR5792wofX4MhfM=; b=Q/qjpYmChiHk6d3bxVVA9c4vw6ca/+dFQ+6gPMWpmbcZWJ5JmZhA1UWn0q+h3la2ajSX 6PiUwAACJVI0nHX4sH2xeyFtNHhRz3o+j5R2TM5sfGE7zXMtf6z+59Q6rXYzu3JyWXfC tYG//zJAueUGNN0T3aQW6eZ+8a9lqxx8MV3lM68DYYiSDuJ57UbDBAcy8xSJo/OMbLRI fPclPxgYrktrriyOddNXcJ375J3loPtH73vPBgHPiRGZ5HHbBPuhbKmLWtbcNJe4ZtM5 F+GJDpeoORDqdBjgmRiFWoqAzL8okVGvjn4CYJxDiy1AY+0oNVDk/Xt8+idc5jFlV54M zw== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2u9pjqbvd2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Aug 2019 06:11:11 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7D67Q1i096475; Tue, 13 Aug 2019 06:11:10 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 2u9m0aydn9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Aug 2019 06:11:10 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x7D6B9SB026468; Tue, 13 Aug 2019 06:11:09 GMT Received: from abi.no.oracle.com (/10.172.144.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 12 Aug 2019 23:11:09 -0700 From: Knut Omang To: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, Shuah Khan , Jonathan Corbet , Masahiro Yamada , Michal Marek , Greg Kroah-Hartman , Shreyans Devendra Doshi <0xinfosect0r@gmail.com>, Alan Maguire , Brendan Higgins , Kevin Hilman , Hidenori Yamaji , Frank Rowand , Timothy Bird , Luis Chamberlain , "Theodore Ts'o" , Daniel Vetter , Stephen Boyd , Knut Omang Subject: [RFC 05/19] ktf: Implementation of ktf support for overriding function entry and return. Date: Tue, 13 Aug 2019 08:09:20 +0200 Message-Id: <1fccfe3062ba6c7a2c8171df8e41975e28dae9ec.1565676440.git-series.knut.omang@oracle.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9347 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908130067 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9347 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908130067 Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Alan Maguire This is a very powerful and yet simple way to verify or modify behaviour of kernel calls. It uses the same technique as the error injection framework in kernel/fail_function.c to to override function entry and return. In addition to error injection, this is very useful to for instance verify that a particular API actually ends up being called, and in the right way, as an effect of a test. ktf_override.c: support for overriding function entry. ktf_override.h: Function override support interface for KTF. Signed-off-by: Alan Maguire Signed-off-by: Knut Omang --- tools/testing/selftests/ktf/kernel/ktf_override.c | 45 ++++++++++++++++- tools/testing/selftests/ktf/kernel/ktf_override.h | 15 +++++- 2 files changed, 60 insertions(+) create mode 100644 tools/testing/selftests/ktf/kernel/ktf_override.c create mode 100644 tools/testing/selftests/ktf/kernel/ktf_override.h diff --git a/tools/testing/selftests/ktf/kernel/ktf_override.c b/tools/testing/selftests/ktf/kernel/ktf_override.c new file mode 100644 index 0000000..7f046c8 --- /dev/null +++ b/tools/testing/selftests/ktf/kernel/ktf_override.c @@ -0,0 +1,45 @@ +/* + * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. + * Author: Alan Maguire + * + * SPDX-License-Identifier: GPL-2.0 + * + * ktf_override.c: support for overriding function entry. + */ +#include +#include +#include "ktf.h" +#include "ktf_override.h" + +asmlinkage void ktf_just_return_func(void); + +asm( + ".type ktf_just_return_func, @function\n" + ".globl ktf_just_return_func\n" + "ktf_just_return_func:\n" + " ret\n" + ".size ktf_just_return_func, .-ktf_just_return_func\n" +); + +void ktf_post_handler(struct kprobe *kp, struct pt_regs *regs, + unsigned long flags) +{ + /* + * A dummy post handler is required to prohibit optimizing, because + * jump optimization does not support execution path overriding. + */ +} +EXPORT_SYMBOL(ktf_post_handler); + +void ktf_override_function_with_return(struct pt_regs *regs) +{ + KTF_SET_INSTRUCTION_POINTER(regs, (unsigned long)&ktf_just_return_func); +} +EXPORT_SYMBOL(ktf_override_function_with_return); +NOKPROBE_SYMBOL(ktf_override_function_with_return); + +int ktf_register_override(struct kprobe *kp) +{ + return register_kprobe(kp); +} +EXPORT_SYMBOL(ktf_register_override); diff --git a/tools/testing/selftests/ktf/kernel/ktf_override.h b/tools/testing/selftests/ktf/kernel/ktf_override.h new file mode 100644 index 0000000..8a9cf39 --- /dev/null +++ b/tools/testing/selftests/ktf/kernel/ktf_override.h @@ -0,0 +1,15 @@ +/* + * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. + * Author: Alan Maguire + * + * SPDX-License-Identifier: GPL-2.0 + * + * ktf_override.h: Function override support interface for KTF. + */ +#include +#include "ktf.h" + +void ktf_post_handler(struct kprobe *kp, struct pt_regs *regs, + unsigned long flags); +void ktf_override_function_with_return(struct pt_regs *regs); +int ktf_register_override(struct kprobe *kp);