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 X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 16E8FC433E6 for ; Tue, 5 Jan 2021 18:28:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B55CA22CE3 for ; Tue, 5 Jan 2021 18:28:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B55CA22CE3 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 223E08D009A; Tue, 5 Jan 2021 13:28:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1D43E8D0099; Tue, 5 Jan 2021 13:28:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0C2C78D009A; Tue, 5 Jan 2021 13:28:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0149.hostedemail.com [216.40.44.149]) by kanga.kvack.org (Postfix) with ESMTP id EAD5D8D0099 for ; Tue, 5 Jan 2021 13:28:08 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 86B343629 for ; Tue, 5 Jan 2021 18:28:08 +0000 (UTC) X-FDA: 77672555856.02.mass53_1106d69274db Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 5DB2710097AA1 for ; Tue, 5 Jan 2021 18:28:08 +0000 (UTC) X-HE-Tag: mass53_1106d69274db X-Filterd-Recvd-Size: 5642 Received: from mail-qv1-f74.google.com (mail-qv1-f74.google.com [209.85.219.74]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Tue, 5 Jan 2021 18:28:07 +0000 (UTC) Received: by mail-qv1-f74.google.com with SMTP id l3so371987qvr.10 for ; Tue, 05 Jan 2021 10:28:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=VRs7dAB+P//KjkP9Cahy8mQRvB3cL9kKzxtAOErS7Qw=; b=RE48ZQIZwfMOj+AkhGO6anvwdkXrBxQVgj8nZblRXvhe5GH4a526P74jpgDRFjV28c 5oFDwhgsmhCAdSpm4Jl8BHqucXqzQGbFI1MO2Ca3Sd5cED98rZKoFwJ2aFQoqvtOlcpX P3fAMVY4fhum/BNZLPkVNfbSI8/jnhxrc31oeRFqD27H46T9wfsnDoj+Ieftt5LyHzx+ ZKBzJLBtVFB6uE1iZMgZr/TVbaIuauem3QVFE3ODS0ATQvTmIHyH9MTLRZcQjvU2Dyhz 9A2/hi/xaSEQ1s5NN+YQtmGbk2PkuuzxdNkqnM5LirdSwLN9sI2EuoL72W/KuSDCQF/+ OXgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=VRs7dAB+P//KjkP9Cahy8mQRvB3cL9kKzxtAOErS7Qw=; b=DNe5Ef8UHirnLgdmOy1c69Ws6u1SG1sBbf3ZjbfTZY8P0+Rm4DhsrSsxow689RZ64U DNXnY7ZG/SwJvJU3dlehy3qDCZQprMUg6iUTt29ZWZL3tniw/FNJeW4whlgXBPg9eFiP w6xLh7JhKr2o2cdkv4XgG/xC5k0yFcSxzG7Ngdm6UW4T93nj+MyaFMp/Nitb+Q0LbyGy +P3Yd5glRPcpI+E1sSQxRMdIzqTcox5+rmXXDLdlrjAY86C90jbgHJ3rXdYFwEoGy/BR +BRlqA3wbEe6tR1LKS2hs5aJYzRQtrMIV3mOPojIEszGNcvsTlqB1W8axOM8Mv+IxI7o cljQ== X-Gm-Message-State: AOAM530o2DlIdKndCnLAcdDurrweeAem9BQCfjuQODJOlBRoMt5SFWpi J/PowV+9QkQReHNqgRBPsYJfEAZ68T0FJcwB X-Google-Smtp-Source: ABdhPJxs7jsjH84m07SSwoqwOtTTJLJPT0usU1rxQ6d4O9vZHQndB+TM03WuWDwAEbVn2jHGgQ6EAgLEVWCFhVAp X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a05:6214:684:: with SMTP id r4mr745500qvz.54.1609871287214; Tue, 05 Jan 2021 10:28:07 -0800 (PST) Date: Tue, 5 Jan 2021 19:27:46 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.729.g45daf8777d-goog Subject: [PATCH 02/11] kasan: clarify HW_TAGS impact on TBI From: Andrey Konovalov To: Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Marco Elver Cc: Andrew Morton , Will Deacon , Andrey Ryabinin , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Mention in the documentation that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI (Top Byte Ignore) being enabled. Also do a few minor documentation cleanups. Signed-off-by: Andrey Konovalov Link: https://linux-review.googlesource.com/id/Iba2a6697e3c6304cb53f89ec61dedc77fa29e3ae --- Documentation/dev-tools/kasan.rst | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 0fc3fb1860c4..26c99852a852 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -147,15 +147,14 @@ negative values to distinguish between different kinds of inaccessible memory like redzones or freed memory (see mm/kasan/kasan.h). In the report above the arrows point to the shadow byte 03, which means that -the accessed address is partially accessible. - -For tag-based KASAN this last report section shows the memory tags around the -accessed address (see `Implementation details`_ section). +the accessed address is partially accessible. For tag-based KASAN modes this +last report section shows the memory tags around the accessed address +(see the `Implementation details`_ section). Boot parameters ~~~~~~~~~~~~~~~ -Hardware tag-based KASAN mode (see the section about different mode below) is +Hardware tag-based KASAN mode (see the section about various modes below) is intended for use in production as a security mitigation. Therefore it supports boot parameters that allow to disable KASAN competely or otherwise control particular KASAN features. @@ -305,6 +304,13 @@ reserved to tag freed memory regions. Hardware tag-based KASAN currently only supports tagging of kmem_cache_alloc/kmalloc and page_alloc memory. +If the hardware doesn't support MTE (pre ARMv8.5), hardware tag-based KASAN +won't be enabled. In this case all boot parameters are ignored. + +Note, that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI being +enabled. Even when kasan.mode=off is provided, or when the hardware doesn't +support MTE (but supports TBI). + What memory accesses are sanitised by KASAN? -------------------------------------------- -- 2.29.2.729.g45daf8777d-goog