From patchwork Fri Jan 15 17:52:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 12023541 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=-16.5 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, URIBL_BLOCKED,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 54CB7C433E0 for ; Fri, 15 Jan 2021 17:53:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F25F8221FA for ; Fri, 15 Jan 2021 17:53:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F25F8221FA 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 837228D01C5; Fri, 15 Jan 2021 12:53:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7BAA38D01C4; Fri, 15 Jan 2021 12:53:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 61A9B8D01C2; Fri, 15 Jan 2021 12:53:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0186.hostedemail.com [216.40.44.186]) by kanga.kvack.org (Postfix) with ESMTP id 455468D01C2 for ; Fri, 15 Jan 2021 12:53:06 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 066BF8017B2C for ; Fri, 15 Jan 2021 17:53:06 +0000 (UTC) X-FDA: 77708755572.24.coat60_3513b3b27531 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id D70D31A4A5 for ; Fri, 15 Jan 2021 17:53:05 +0000 (UTC) X-HE-Tag: coat60_3513b3b27531 X-Filterd-Recvd-Size: 5790 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 Jan 2021 17:53:05 +0000 (UTC) Received: by mail-wm1-f74.google.com with SMTP id z188so3465377wme.1 for ; Fri, 15 Jan 2021 09:53:05 -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=d+lRqXXla6mV/kMKnUzgl/DAB69C3QZUVHCf/SWSD4s=; b=KgXsADO6gYG+QvJv8VSvdUb8Ltjmd7v7h/iXf4vB+MUx9Hgoo/jNS+Vf6CaL2wEuKc iZx+uRlsmSmChjKZB8PeM+2dY6z/JyFIFLWBbNw1VAx4D2M/iXObjUzCZ7fBSfeX3u0r 5YfdIu95gEZandu93MmDpCwNWtqhZpPlSmmjfvOZLYE9Sbuujc+aqXC2qj2elqLEJ9VM RaDCLzvWaX5/2oD76eVUv0i6nIfmJk8vOryRmLyptUhh9nWI1mtpqlx+Yn/uT4oybi6f oNtAzPYrqpulLvHqnis8loKBQl943FBAFrdnh9YV5x3XZP96MO3+h0totSFQGrfhOew9 8ylg== 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=d+lRqXXla6mV/kMKnUzgl/DAB69C3QZUVHCf/SWSD4s=; b=p/A4sar/YcthQyJgRS/LHXiJlOj1kDU3OMjztVI0WyaMkz0h12E1/VkAyagzx2t466 12M9vfnHp+5cQrWpP29IcpyzJQdrnQlZ5/CiiwlhZkHhJcUourrZBxj7jR7APgvftv/I GT1Ng45TvEfGOGTJrktqrxryy8O6iDjjBJjzS6YqaE9tshkuQmGFdrLQo0IOZF4dXR69 uxxxabEshA7avTdwxOiqQqXR4izJNm7F0iZj/yqebFVbe3uZRmJvfDxEhZWk05v1EEAY YCaI8NTZDZQmZ3SwJEg3/FWW55ASgfmrdq3x8GayH4IxhCJdfLTSF6nFFUeqGbhlQww9 69CA== X-Gm-Message-State: AOAM531uEf2CsDlf5vwN+MiAvsz5hidPBb+E4J/psq0sGOWa8Ksp4+jj agC1pQP+SYl3Sf4G9lYQ/0WbTgPVBpslP75D X-Google-Smtp-Source: ABdhPJxUL79lbHyM9ib1bYpCh98XNU7ltPS1uDYDg7Hf/2+vn3e8C3YxAqL9xZFwJzAt5tybo0F8O9/8zxE6C0yc X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:adf:e60f:: with SMTP id p15mr14224523wrm.60.1610733184113; Fri, 15 Jan 2021 09:53:04 -0800 (PST) Date: Fri, 15 Jan 2021 18:52:39 +0100 In-Reply-To: Message-Id: <3b4ea6875bb14d312092ad14ac55cb456c83c08e.1610733117.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v4 02/15] kasan: clarify HW_TAGS impact on TBI From: Andrey Konovalov To: Andrew Morton , Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Marco Elver Cc: Will Deacon , Andrey Ryabinin , Peter Collingbourne , 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 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. Link: https://linux-review.googlesource.com/id/Iba2a6697e3c6304cb53f89ec61dedc77fa29e3ae Reviewed-by: Marco Elver Reviewed-by: Alexander Potapenko Signed-off-by: Andrey Konovalov --- 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? --------------------------------------------