From patchwork Sat Jan 30 00:24:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Widawsky X-Patchwork-Id: 12057081 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,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 983B5C433E0 for ; Sat, 30 Jan 2021 10:20:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40D3A64E05 for ; Sat, 30 Jan 2021 10:20:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231941AbhA3KU3 (ORCPT ); Sat, 30 Jan 2021 05:20:29 -0500 Received: from mga01.intel.com ([192.55.52.88]:38338 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231297AbhA3A3X (ORCPT ); Fri, 29 Jan 2021 19:29:23 -0500 IronPort-SDR: Uc83Y3ukXLDuJd/HgkPVd4KDUXQqmrquaiGh2G1w2YuT8xwxrt70Tgw9ddlp+Tbw+ICeTnPbPu hJNg1/6NyfsQ== X-IronPort-AV: E=McAfee;i="6000,8403,9879"; a="199350690" X-IronPort-AV: E=Sophos;i="5.79,387,1602572400"; d="scan'208";a="199350690" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 16:24:49 -0800 IronPort-SDR: m7fLWpnzSaGDDMzkIoKQE1gcfDJtpyuPc8V2ww1bEY8aPomuNC709+efCr5+o4CuEcZOz7049/ ppIAmMFJlyyg== X-IronPort-AV: E=Sophos;i="5.79,387,1602572400"; d="scan'208";a="370591682" Received: from jambrizm-mobl1.amr.corp.intel.com (HELO bwidawsk-mobl5.local) ([10.252.133.15]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 16:24:49 -0800 From: Ben Widawsky To: linux-cxl@vger.kernel.org Cc: Ben Widawsky , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org, Bjorn Helgaas , Chris Browy , Christoph Hellwig , Dan Williams , Ira Weiny , Jon Masters , Jonathan Cameron , Rafael Wysocki , Randy Dunlap , Vishal Verma , daniel.lll@alibaba-inc.com, "John Groves (jgroves)" , "Kelley, Sean V" Subject: [PATCH 08/14] taint: add taint for direct hardware access Date: Fri, 29 Jan 2021 16:24:32 -0800 Message-Id: <20210130002438.1872527-9-ben.widawsky@intel.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210130002438.1872527-1-ben.widawsky@intel.com> References: <20210130002438.1872527-1-ben.widawsky@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org For drivers that moderate access to the underlying hardware it is sometimes desirable to allow userspace to bypass restrictions. Once userspace has done this, the driver can no longer guarantee the sanctity of either the OS or the hardware. When in this state, it is helpful for kernel developers to be made aware (via this taint flag) of this fact for subsequent bug reports. Example usage: - Hardware xyzzy accepts 2 commands, waldo and fred. - The xyzzy driver provides an interface for using waldo, but not fred. - quux is convinced they really need the fred command. - xyzzy driver allows quux to frob hardware to initiate fred. - kernel gets tainted. - turns out fred command is borked, and scribbles over memory. - developers laugh while closing quux's subsequent bug report. Signed-off-by: Ben Widawsky --- Documentation/admin-guide/sysctl/kernel.rst | 1 + Documentation/admin-guide/tainted-kernels.rst | 6 +++++- include/linux/kernel.h | 3 ++- kernel/panic.c | 1 + 4 files changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 1d56a6b73a4e..3e1eada53504 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -1352,6 +1352,7 @@ ORed together. The letters are seen in "Tainted" line of Oops reports. 32768 `(K)` kernel has been live patched 65536 `(X)` Auxiliary taint, defined and used by for distros 131072 `(T)` The kernel was built with the struct randomization plugin +262144 `(H)` The kernel has allowed vendor shenanigans ====== ===== ============================================================== See :doc:`/admin-guide/tainted-kernels` for more information. diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index ceeed7b0798d..ee2913316344 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -74,7 +74,7 @@ a particular type of taint. It's best to leave that to the aforementioned script, but if you need something quick you can use this shell command to check which bits are set:: - $ for i in $(seq 18); do echo $(($i-1)) $(($(cat /proc/sys/kernel/tainted)>>($i-1)&1));done + $ for i in $(seq 19); do echo $(($i-1)) $(($(cat /proc/sys/kernel/tainted)>>($i-1)&1));done Table for decoding tainted state ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -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 _/H 262144 kernel has allowed vendor shenanigans === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading @@ -175,3 +176,6 @@ More detailed explanation for tainting produce extremely unusual kernel structure layouts (even performance pathological ones), which is important to know when debugging. Set at build time. + + 18) ``H`` Kernel has allowed direct access to hardware and can no longer make + any guarantees about the stability of the device or driver. diff --git a/include/linux/kernel.h b/include/linux/kernel.h index f7902d8c1048..bc95486f817e 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -443,7 +443,8 @@ extern enum system_states { #define TAINT_LIVEPATCH 15 #define TAINT_AUX 16 #define TAINT_RANDSTRUCT 17 -#define TAINT_FLAGS_COUNT 18 +#define TAINT_RAW_PASSTHROUGH 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 332736a72a58..dff22bd80eaf 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -386,6 +386,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, [ TAINT_AUX ] = { 'X', ' ', true }, [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, + [ TAINT_RAW_PASSTHROUGH ] = { 'H', ' ', true }, }; /**