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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 D9199C43464 for ; Fri, 18 Sep 2020 15:00:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64B9921973 for ; Fri, 18 Sep 2020 15:00:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZwMp8rTY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726497AbgIRPAS (ORCPT ); Fri, 18 Sep 2020 11:00:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726154AbgIRPAS (ORCPT ); Fri, 18 Sep 2020 11:00:18 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C63B1C0613CE for ; Fri, 18 Sep 2020 08:00:17 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id e4so3112886pln.10 for ; Fri, 18 Sep 2020 08:00:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=43HOBOFmwhtePq8PeIBCEBCa6ILf8VtzLC2fB6iIXLI=; b=ZwMp8rTYude/m8e4AjpmPmYXmn1OyxxT0b81WxynRHwoKm5tuUil33CmvmAZC7k0Qu TIEgiSbT4v0NU7cFsGzdRTvKOGW/Piv7H5wYRnVqEaU2LdXftO30ow2qZr5LU/jGZs/F LU0/2O1pWp1thAILGKv55VJq5nuPvIJBDsDilogN4vevzKSrySLFVRNmItHNNfeuCyQE Ex3P75hm8fMhl2CoWyzJkUzjOwf6PxqnKaJEIo0oDwCzQP89NgWfdZylrEp3KNY0CczH flk3gVjF/lb44LmKGwYnAS2Uzb7URYTYVhVHoT2+qzczraIj3fKQFeN5v7Lits9zP4yY w69w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=43HOBOFmwhtePq8PeIBCEBCa6ILf8VtzLC2fB6iIXLI=; b=fpRUH4wuJ2Qy9XilD8a9oNvFLwUpAouoVEpw1/Ag8cUBSaSiF883wlbbfjAMxn9RxB HgK4Mb/2ehjceQ9uFwGa5yVDtUbLzkmFmgcTAv9Wn1qGGxAjvfwQXFMSRbEqW044NCWR MMHMXNql7Ar94fNprh53gLKJAKjiylQuYtrs2gBWJpj0uWck69ERmLYbNVupRs/sGf3U flbgvxvv5LOuq9Ar/p6sA91hySJy5HQp8YRxjmwdVo2B9MQVH/txDMqgGMD+kWqMkkdo gEayVf9balgJ4Gq3NFQYoqispQey2PNgD6/jHCANL/IIss6ObB9I1sWZrORfxY7pjcw0 bxlQ== X-Gm-Message-State: AOAM531TGEQN13NfrrLfHXP/9iCmI2sJ4bURen3xJCGOe2aAg9MWOlMe rMvR6YSEA/ipORtqC3H5uRYEWzVpwrKf1w83AEZOeXNnU/Ys3A== X-Google-Smtp-Source: ABdhPJxzGZXU3x/rtx4bWTn+tg8BBnZsw9+h4p5kvRQigJEqvqcpV9eMKwoMwAXnogjuZ+Hlr5Ql3jaPFhNeu+MiVlU= X-Received: by 2002:a17:902:b117:b029:d1:e5e7:bdf5 with SMTP id q23-20020a170902b117b02900d1e5e7bdf5mr15071472plr.85.1600441216910; Fri, 18 Sep 2020 08:00:16 -0700 (PDT) MIME-Version: 1.0 References: <74133d1a57c47cb8fec791dd5d1e6417b0579fc3.1600204505.git.andreyknvl@google.com> <20200918125216.GD2384246@elver.google.com> In-Reply-To: <20200918125216.GD2384246@elver.google.com> From: Andrey Konovalov Date: Fri, 18 Sep 2020 17:00:06 +0200 Message-ID: Subject: Re: [PATCH v2 33/37] kasan, arm64: implement HW_TAGS runtime To: Marco Elver Cc: Dmitry Vyukov , Vincenzo Frascino , Catalin Marinas , kasan-dev , Andrey Ryabinin , Alexander Potapenko , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 18, 2020 at 2:52 PM Marco Elver wrote: > > [ Sorry for the additional email on this patch; trying to consolidate > comments now. ] > > On Tue, Sep 15, 2020 at 11:16PM +0200, Andrey Konovalov wrote: > > Provide implementation of KASAN functions required for the hardware > > tag-based mode. Those include core functions for memory and pointer > > tagging (tags_hw.c) and bug reporting (report_tags_hw.c). Also adapt > > common KASAN code to support the new mode. > > > > Signed-off-by: Andrey Konovalov > > Signed-off-by: Vincenzo Frascino > > --- > > Change-Id: I8a8689ba098174a4d0ef3f1d008178387c80ee1c > > --- > > arch/arm64/include/asm/memory.h | 4 +- > > arch/arm64/kernel/setup.c | 1 - > > include/linux/kasan.h | 6 +-- > > include/linux/mm.h | 2 +- > > include/linux/page-flags-layout.h | 2 +- > > mm/kasan/Makefile | 5 ++ > > mm/kasan/common.c | 14 +++--- > > mm/kasan/kasan.h | 17 +++++-- > > mm/kasan/report_tags_hw.c | 47 +++++++++++++++++++ > > mm/kasan/report_tags_sw.c | 2 +- > > mm/kasan/shadow.c | 2 +- > > mm/kasan/tags_hw.c | 78 +++++++++++++++++++++++++++++++ > > mm/kasan/tags_sw.c | 2 +- > > 13 files changed, 162 insertions(+), 20 deletions(-) > > create mode 100644 mm/kasan/report_tags_hw.c > > create mode 100644 mm/kasan/tags_hw.c > [...] > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index 41c7f1105eaa..412a23d1546b 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -118,7 +118,7 @@ void kasan_free_pages(struct page *page, unsigned int order) > > */ > > static inline unsigned int optimal_redzone(unsigned int object_size) > > { > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > > + if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) > > return 0; > > > > return > > @@ -183,14 +183,14 @@ size_t kasan_metadata_size(struct kmem_cache *cache) > > struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, > > const void *object) > > { > > - return (void *)object + cache->kasan_info.alloc_meta_offset; > > + return (void *)reset_tag(object) + cache->kasan_info.alloc_meta_offset; > > } > > > > struct kasan_free_meta *get_free_info(struct kmem_cache *cache, > > const void *object) > > { > > BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); > > - return (void *)object + cache->kasan_info.free_meta_offset; > > + return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset; > > } > > > > void kasan_poison_slab(struct page *page) > > @@ -272,7 +272,8 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > > alloc_info = get_alloc_info(cache, object); > > __memset(alloc_info, 0, sizeof(*alloc_info)); > > Suggested edit below (assuming the line-break wasn't intentional; this > should still be within checkpatch.pl's 100 col limit): > ------ > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > - IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > object = set_tag(object, > assign_tag(cache, object, true, false)); > > @@ -343,8 +342,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > redzone_end = round_up((unsigned long)object + cache->object_size, > KASAN_GRANULE_SIZE); > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > - IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > tag = assign_tag(cache, object, false, keep_tag); > ------ > > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > > + IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > > object = set_tag(object, > > assign_tag(cache, object, true, false)); > > > > @@ -342,10 +343,11 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > > redzone_end = round_up((unsigned long)object + cache->object_size, > > KASAN_GRANULE_SIZE); > > > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > > + IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > > tag = assign_tag(cache, object, false, keep_tag); > > > > - /* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */ > > + /* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */ > > kasan_unpoison_memory(set_tag(object, tag), size); > > kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start, > > KASAN_KMALLOC_REDZONE); > [...] > > diff --git a/mm/kasan/report_tags_hw.c b/mm/kasan/report_tags_hw.c > > new file mode 100644 > > index 000000000000..c2f73c46279a > > --- /dev/null > > +++ b/mm/kasan/report_tags_hw.c > > @@ -0,0 +1,47 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * This file contains hardware tag-based KASAN specific error reporting code. > > + * > > + * Copyright (c) 2020 Google, Inc. > > + * Author: Andrey Konovalov > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > I do not think we put the "This program is ..." preamble in new files > anymore. It should be covered by SPDX tag above. > > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > [...] > > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > > index 4888084ecdfc..ca69726adf8f 100644 > > --- a/mm/kasan/shadow.c > > +++ b/mm/kasan/shadow.c > > @@ -111,7 +111,7 @@ void kasan_unpoison_memory(const void *address, size_t size) > > > > if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > > *shadow = tag; > > - else > > + else /* CONFIG_KASAN_GENERIC */ > > *shadow = size & KASAN_GRANULE_MASK; > > } > > } > > diff --git a/mm/kasan/tags_hw.c b/mm/kasan/tags_hw.c > > new file mode 100644 > > index 000000000000..c93d43379e39 > > --- /dev/null > > +++ b/mm/kasan/tags_hw.c > > @@ -0,0 +1,78 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * This file contains core hardware tag-based KASAN code. > > + * > > + * Copyright (c) 2020 Google, Inc. > > + * Author: Andrey Konovalov > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > I do not think we put the "This program is ..." preamble in new files > anymore. It should be covered by SPDX tag above. > > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#include "kasan.h" > > + > > +void kasan_init_tags(void) > > +{ > > + init_tags(KASAN_TAG_MAX); > > +} > > + > > +void *kasan_reset_tag(const void *addr) > > +{ > > + return reset_tag(addr); > > +} > > + > > To help readability, would this edit be ok? > ------ > void kasan_poison_memory(const void *address, size_t size, u8 value) > { > - set_mem_tag_range(reset_tag(address), > - round_up(size, KASAN_GRANULE_SIZE), value); > + set_mem_tag_range(reset_tag(address), round_up(size, KASAN_GRANULE_SIZE), value); > } > > void kasan_unpoison_memory(const void *address, size_t size) > { > - set_mem_tag_range(reset_tag(address), > - round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); > + set_mem_tag_range(reset_tag(address), round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); > } > ------ > > > +void kasan_poison_memory(const void *address, size_t size, u8 value) > > +{ > > + set_mem_tag_range(reset_tag(address), > > + round_up(size, KASAN_GRANULE_SIZE), value); > > +} > > + > > +void kasan_unpoison_memory(const void *address, size_t size) > > +{ > > + set_mem_tag_range(reset_tag(address), > > + round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); > > +} > > + > > +u8 random_tag(void) > > +{ > > + return get_random_tag(); > > +} > > + > > +bool check_invalid_free(void *addr) > > +{ > > + u8 ptr_tag = get_tag(addr); > > + u8 mem_tag = get_mem_tag(addr); > > + > > > Why not just: > ------ > - if (shadow_byte == KASAN_TAG_INVALID) > - return true; > - if (tag != KASAN_TAG_KERNEL && tag != shadow_byte) > - return true; > - return false; > + return shadow_byte == KASAN_TAG_INVALID || > + (tag != KASAN_TAG_KERNEL && tag != shadow_byte); > } > ------ > > > + if (mem_tag == KASAN_TAG_INVALID) > > + return true; > > + if (ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag) > > + return true; > > + return false; > > +} > > + Will fix all these in v3, thanks!