From patchwork Fri May 13 08:32:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gow X-Patchwork-Id: 12848484 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 91543C433EF for ; Fri, 13 May 2022 08:32:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378292AbiEMIcd (ORCPT ); Fri, 13 May 2022 04:32:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241051AbiEMIcb (ORCPT ); Fri, 13 May 2022 04:32:31 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDD6564BC8 for ; Fri, 13 May 2022 01:32:27 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-2f7ee6bc6ddso66923457b3.1 for ; Fri, 13 May 2022 01:32:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=hUQluwx+IeHDQbtP0fjL9XDhdITsEoJIWpp8L9h5giw=; b=F/cDv7XyzfAhrhFHas6iEitptBabeLxs7JYySMnnIYCMoVWQlm1aMRtE+/SqhaEDNm CUtVY8Whw9qTUb+f6i/9SrNwUqK//hLviYObbOgELsaAp+e5PQTys3VZGSOL11haUR2h JXi3PzXSBFhTXTg6T1Af2lQ5jg98qlb1DqYvd/5im6SSwHSqg3+18b/zRgwbpeniHh5w dFaHx//RRMeVVvYwkpThQ2ynlPG4D3Z6TPN9+uRk3fk2kHCiIjA3uT5TTFvKie7Uwrfj xvGnEU8+v1psGFcZQC5sVKJwY5jyAB/aWooaKwolISkK6dLklWtYlS3y29i6SEb8U5+M i2xA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=hUQluwx+IeHDQbtP0fjL9XDhdITsEoJIWpp8L9h5giw=; b=7XzN0jwU2AHsF64b0bPoO79/jf7ZA3CWHrD7unD06u1O6mml9LLGf//JKWb1ddGfmQ tDfduiEK7lYAsznoWacijjpT5dfAhjJFMakflrivQXya2vg3fj0mWMwULwfCnIAbAR3F fqJH4B49MwZ5/8wAxiiJlo8/Ag8Ob3z8BNg8oBJJe3JxY//sDc9b/8+kQg1F/n1ail6k rwPeDnQWha4eo7jUJWsacgKYT9CRu9WFYu1IiCoqZz6l5v7zOMYAnosHiOK8ZxUheyK8 Y6ppiBKtrHbOZBbsY1iCKLo7GVR4Yo4bB6PMJ5ianBP9JyYkOOlK19U5vZFGcSWD+ePP QZew== X-Gm-Message-State: AOAM533sefDn/2Zz6KrF1qiJIYarhk6CETFWDZyc55mZw6khnXhhgcLi AVWF0TNwCK55QtBKoXoJNa7meqn+U+rgcw== X-Google-Smtp-Source: ABdhPJz63iUUnCr3zTam4iVPENkFDo9Hk9l7LA5hxnjO3aj6X2c1blool5DQ+WglykBzpsoKBGog87zoHV/MCQ== X-Received: from slicestar.c.googlers.com ([fda3:e722:ac3:cc00:4f:4b78:c0a8:20a1]) (user=davidgow job=sendgmr) by 2002:a0d:d689:0:b0:2fb:9a57:8517 with SMTP id y131-20020a0dd689000000b002fb9a578517mr4235720ywd.502.1652430747159; Fri, 13 May 2022 01:32:27 -0700 (PDT) Date: Fri, 13 May 2022 16:32:11 +0800 In-Reply-To: <20220429043913.626647-1-davidgow@google.com> Message-Id: <20220513083212.3537869-1-davidgow@google.com> Mime-Version: 1.0 References: <20220429043913.626647-1-davidgow@google.com> X-Mailer: git-send-email 2.36.0.550.gb090851708-goog Subject: [PATCH v3 1/3] panic: Taint kernel if tests are run From: David Gow To: Brendan Higgins , Andy Shevchenko , Jonathan Corbet , Andrew Morton , Kees Cook , Shuah Khan , Greg KH , Luis Chamberlain Cc: David Gow , "Guilherme G . Piccoli" , Sebastian Reichel , John Ogness , Joe Fradley , Daniel Latypov , kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Jani Nikula , Lucas De Marchi , Aaron Tomlin , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Most in-kernel tests (such as KUnit tests) are not supposed to run on production systems: they may do deliberately illegal things to trigger errors, and have security implications (for example, KUnit assertions will often deliberately leak kernel addresses). Add a new taint type, TAINT_TEST to signal that a test has been run. This will be printed as 'N' (originally for kuNit, as every other sensible letter was taken.) This should discourage people from running these tests on production systems, and to make it easier to tell if tests have been run accidentally (by loading the wrong configuration, etc.) Signed-off-by: David Gow Acked-by: Luis Chamberlain Reviewed-by: Brendan Higgins --- Updated this to handle the most common case of selftest modules, in addition to KUnit tests. There's room for other tests or test frameworks to use this as well, either with a call to add_taint() from within the kernel, or by writing to /proc/sys/kernel/tainted. The 'N' character for the taint is even less useful now that it's no longer short for kuNit, but all the letters in TEST are taken. :-( Changes since v2: https://lore.kernel.org/linux-kselftest/20220430030019.803481-1-davidgow@google.com/ - Rename TAINT_KUNIT -> TAINT_TEST. - Split into separate patches for adding the taint, and triggering it. - Taint on a kselftest_module being loaded (patch 3/3) Changes since v1: https://lore.kernel.org/linux-kselftest/20220429043913.626647-1-davidgow@google.com/ - Make the taint per-module, to handle the case when tests are in (longer lasting) modules. (Thanks Greg KH). Note that this still has checkpatch.pl warnings around bracket placement, which are intentional as part of matching the surrounding code. --- Documentation/admin-guide/tainted-kernels.rst | 1 + include/linux/panic.h | 3 ++- kernel/panic.c | 1 + 3 files changed, 4 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index ceeed7b0798d..546f3071940d 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -100,6 +100,7 @@ Bit Log Number Reason that got the kernel tainted 15 _/K 32768 kernel has been live patched 16 _/X 65536 auxiliary taint, defined for and used by distros 17 _/T 131072 kernel was built with the struct randomization plugin + 18 _/N 262144 an in-kernel test (such as a KUnit test) has been run === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading diff --git a/include/linux/panic.h b/include/linux/panic.h index f5844908a089..2f5f2a9ecaf7 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -74,7 +74,8 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout) #define TAINT_LIVEPATCH 15 #define TAINT_AUX 16 #define TAINT_RANDSTRUCT 17 -#define TAINT_FLAGS_COUNT 18 +#define TAINT_TEST 18 +#define TAINT_FLAGS_COUNT 19 #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1) struct taint_flag { diff --git a/kernel/panic.c b/kernel/panic.c index eb4dfb932c85..1cf707e3bacd 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -404,6 +404,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, [ TAINT_AUX ] = { 'X', ' ', true }, [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, + [ TAINT_TEST ] = { 'N', ' ', true }, }; /**