From patchwork Wed Jun 20 17:40:01 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10478335 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D34F760532 for ; Wed, 20 Jun 2018 17:44:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BF4C928E08 for ; Wed, 20 Jun 2018 17:44:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B34AD28E82; Wed, 20 Jun 2018 17:44:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0BA7928E08 for ; Wed, 20 Jun 2018 17:44:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933074AbeFTRoe (ORCPT ); Wed, 20 Jun 2018 13:44:34 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:52058 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932170AbeFTRkd (ORCPT ); Wed, 20 Jun 2018 13:40:33 -0400 Received: by mail-wm0-f65.google.com with SMTP id r15-v6so872655wmc.1 for ; Wed, 20 Jun 2018 10:40:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=xX2ve6cw6mFUYv1ZVga1FuvdMG14IXrzqrH0SkKm2o8=; b=K4YJEGyqFIkTF9RHoK2WVKMhr7GR2/AM6oiVDpBIojyTrXFrhijYAh5Heo3YperCUS lFTBqIf2Xw66cKJgJWwlFyNSzK1J+I/4XIjua9NKR4gOdfLF6U7TmKng7idYqfyqiNjl eRXlLpmwud5fwBMo1G3w2QoZVORTe9dsb5KvY+fscH+neMzh33hlQPNcRQNg1vfyAid1 mUmel2k9CCVY/gOpd2j8xjkBbHI1B0SkWMTP3OR0CtJ3f47rSQ6vcrW9qCbc3o75d8EB z0ueLYL7mgxIx5ORP6A+XfNorCTOYxSJDlf/+BZfW/ODWoCnyBXYZkiwFCWMfzzQ+C7L Wj0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=xX2ve6cw6mFUYv1ZVga1FuvdMG14IXrzqrH0SkKm2o8=; b=Vd6GPuYCA7UCvloDMdwds3OI+TQDhOi5N9AcnvXOtyLCG+o8nCZXBi7xGJC+Eayyp/ nJOZuun0tNsLAzINXfOAdnnR9WmT+MoULsyOFYu56gD3Sg6frMJyLcpTo1WmBiRIiR5q lKnwgrWEuMxxmOnAh95O3f+TTYj16wBqm4yhuiuy5bLPiFFqfucaGtm2rxg5bQy50UfQ 614b0UXF5syUHH+qmj0TlOnCOfs9WFbuubxn7yE+5J12jc9K+27EFJcyPj0Whu1jJF+6 rn3pVP6XQQG4vkLoJ7VU0Fh2bFtmusn/ChreCyAF6+jWV4oyLA76FTW66pNvUhekZ+Zf FDjA== X-Gm-Message-State: APt69E1IGrVBGgn10vZRd+OgCbZcisgGYR5uPnbJ/q+HGYTVbAp65poc Ys2Six3B7uK/raR2vKmu2z3NvQ== X-Google-Smtp-Source: ADUXVKKKTDUWY9MXhSS/25+5wRwGGu8+M0a4PUWzj1MQY/CeY8PAzSrjwg1W3xMv1/t5uidSW5ZGXQ== X-Received: by 2002:a1c:630b:: with SMTP id x11-v6mr2579473wmb.104.1529516431559; Wed, 20 Jun 2018 10:40:31 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id f18-v6sm4388598wro.1.2018.06.20.10.40.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jun 2018 10:40:30 -0700 (PDT) From: Andrey Konovalov To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Catalin Marinas , Will Deacon , Christoph Lameter , Andrew Morton , Mark Rutland , Nick Desaulniers , Marc Zyngier , Dave Martin , Ard Biesheuvel , "Eric W . Biederman" , Ingo Molnar , Paul Lawrence , Geert Uytterhoeven , Arnd Bergmann , "Kirill A . Shutemov" , Greg Kroah-Hartman , Kate Stewart , Mike Rapoport , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sparse@vger.kernel.org, linux-mm@kvack.org, linux-kbuild@vger.kernel.org Cc: Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Jann Horn , Mark Brand , Chintan Pandya , Andrey Konovalov Subject: [PATCH v3 15/17] khwasan, mm, arm64: tag non slab memory allocated via pagealloc Date: Wed, 20 Jun 2018 19:40:01 +0200 Message-Id: <05d48d96bcecdb74bc8b7977634a4c16feb7a465.1529515183.git.andreyknvl@google.com> X-Mailer: git-send-email 2.18.0.rc1.244.gcf134e6275-goog In-Reply-To: References: Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP KWHASAN doesn't check memory accesses through pointers tagged with 0xff. When page_address is used to get pointer to memory that corresponds to some page, the tag of the resulting pointer gets set to 0xff, even though the allocated memory might have been tagged differently. For slab pages it's impossible to recover the correct tag to return from page_address, since the page might contain multiple slab objects tagged with different values, and we can't know in advance which one of them is going to get accessed. For non slab pages however, we can recover the tag in page_address, since the whole page was marked with the same tag. This patch adds tagging to non slab memory allocated with pagealloc. To set the tag of the pointer returned from page_address, the tag gets stored to page->flags when the memory gets allocated. Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/memory.h | 10 ++++++++++ include/linux/mm.h | 29 +++++++++++++++++++++++++++++ include/linux/page-flags-layout.h | 10 ++++++++++ mm/cma.c | 11 +++++++++++ mm/kasan/common.c | 15 +++++++++++++-- mm/page_alloc.c | 1 + 6 files changed, 74 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index e9e054dfb1fc..3352a65b8312 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -305,7 +305,17 @@ static inline void *phys_to_virt(phys_addr_t x) #define __virt_to_pgoff(kaddr) (((u64)(kaddr) & ~PAGE_OFFSET) / PAGE_SIZE * sizeof(struct page)) #define __page_to_voff(kaddr) (((u64)(kaddr) & ~VMEMMAP_START) * PAGE_SIZE / sizeof(struct page)) +#ifndef CONFIG_KASAN_HW #define page_to_virt(page) ((void *)((__page_to_voff(page)) | PAGE_OFFSET)) +#else +#define page_to_virt(page) ({ \ + unsigned long __addr = \ + ((__page_to_voff(page)) | PAGE_OFFSET); \ + __addr = KASAN_SET_TAG(__addr, page_kasan_tag(page)); \ + ((void *)__addr); \ +}) +#endif + #define virt_to_page(vaddr) ((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START)) #define _virt_addr_valid(kaddr) pfn_valid((((u64)(kaddr) & ~PAGE_OFFSET) \ diff --git a/include/linux/mm.h b/include/linux/mm.h index a0fbb9ffe380..46afadf4f48c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -784,6 +784,7 @@ int finish_mkwrite_fault(struct vm_fault *vmf); #define NODES_PGOFF (SECTIONS_PGOFF - NODES_WIDTH) #define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH) #define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH) +#define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH) /* * Define the bit shifts to access each section. For non-existent @@ -794,6 +795,7 @@ int finish_mkwrite_fault(struct vm_fault *vmf); #define NODES_PGSHIFT (NODES_PGOFF * (NODES_WIDTH != 0)) #define ZONES_PGSHIFT (ZONES_PGOFF * (ZONES_WIDTH != 0)) #define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0)) +#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0)) /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */ #ifdef NODE_NOT_IN_PAGE_FLAGS @@ -816,6 +818,7 @@ int finish_mkwrite_fault(struct vm_fault *vmf); #define NODES_MASK ((1UL << NODES_WIDTH) - 1) #define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1) #define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1) +#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1) #define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1) static inline enum zone_type page_zonenum(const struct page *page) @@ -1070,6 +1073,32 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid) } #endif /* CONFIG_NUMA_BALANCING */ +#ifdef CONFIG_KASAN_HW +static inline u8 page_kasan_tag(const struct page *page) +{ + return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; +} + +static inline void page_kasan_tag_set(struct page *page, u8 tag) +{ + page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT); + page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT; +} + +static inline void page_kasan_tag_reset(struct page *page) +{ + page_kasan_tag_set(page, 0xff); +} +#else +static inline u8 page_kasan_tag(const struct page *page) +{ + return 0xff; +} + +static inline void page_kasan_tag_set(struct page *page, u8 tag) { } +static inline void page_kasan_tag_reset(struct page *page) { } +#endif + static inline struct zone *page_zone(const struct page *page) { return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]; diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h index 7ec86bf31ce4..8dbad17664c2 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -82,6 +82,16 @@ #define LAST_CPUPID_WIDTH 0 #endif +#ifdef CONFIG_KASAN_HW +#define KASAN_TAG_WIDTH 8 +#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \ + > BITS_PER_LONG - NR_PAGEFLAGS +#error "KASAN: not enough bits in page flags for tag" +#endif +#else +#define KASAN_TAG_WIDTH 0 +#endif + /* * We are going to use the flags for the page to node mapping if its in * there. This includes the case where there is no node, so it is implicit. diff --git a/mm/cma.c b/mm/cma.c index 5809bbe360d7..fdad7ad0d9c4 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -407,6 +407,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, unsigned long pfn = -1; unsigned long start = 0; unsigned long bitmap_maxno, bitmap_no, bitmap_count; + size_t i; struct page *page = NULL; int ret = -ENOMEM; @@ -466,6 +467,16 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, trace_cma_alloc(pfn, page, count, align); + /* + * CMA can allocate multiple page blocks, which results in different + * blocks being marked with different tags. Reset the tags to ignore + * those page blocks. + */ + if (page) { + for (i = 0; i < count; i++) + page_kasan_tag_reset(page + i); + } + if (ret && !(gfp_mask & __GFP_NOWARN)) { pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", __func__, count, ret); diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 1e96ca050c75..6cf7dec0b765 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -212,8 +212,15 @@ void kasan_unpoison_stack_above_sp_to(const void *watermark) void kasan_alloc_pages(struct page *page, unsigned int order) { + u8 tag; + unsigned long i; + if (unlikely(PageHighMem(page))) return; + + tag = random_tag(); + for (i = 0; i < (1 << order); i++) + page_kasan_tag_set(page + i, tag); kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order); } @@ -311,6 +318,10 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache, void kasan_poison_slab(struct page *page) { + unsigned long i; + + for (i = 0; i < (1 << compound_order(page)); i++) + page_kasan_tag_reset(page + i); kasan_poison_shadow(page_address(page), PAGE_SIZE << compound_order(page), KASAN_KMALLOC_REDZONE); @@ -483,7 +494,7 @@ void kasan_poison_kfree(void *ptr, unsigned long ip) page = virt_to_head_page(ptr); if (unlikely(!PageSlab(page))) { - if (reset_tag(ptr) != page_address(page)) { + if (ptr != page_address(page)) { kasan_report_invalid_free(ptr, ip); return; } @@ -496,7 +507,7 @@ void kasan_poison_kfree(void *ptr, unsigned long ip) void kasan_kfree_large(void *ptr, unsigned long ip) { - if (reset_tag(ptr) != page_address(virt_to_head_page(ptr))) + if (ptr != page_address(virt_to_head_page(ptr))) kasan_report_invalid_free(ptr, ip); /* The object will be poisoned by page_alloc. */ } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1521100f1e63..266e86323d73 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1176,6 +1176,7 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn, init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); + page_kasan_tag_reset(page); INIT_LIST_HEAD(&page->lru); #ifdef WANT_PAGE_VIRTUAL