From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.7 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 1391D7DBEB for ; Tue, 6 Nov 2018 17:30:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389728AbeKGC5K (ORCPT ); Tue, 6 Nov 2018 21:57:10 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:37710 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389677AbeKGC5J (ORCPT ); Tue, 6 Nov 2018 21:57:09 -0500 Received: by mail-wm1-f68.google.com with SMTP id p2-v6so12900661wmc.2 for ; Tue, 06 Nov 2018 09:30:53 -0800 (PST) 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 :mime-version:content-transfer-encoding; bh=Ce4N/nMYo7+RfxBkmlKo7hExteLUxNUpfT4nrnEM84A=; b=Vsfw56KNSA0j9i4jZTEMw40brJDN+L6Vk6DCkdODL+7mPErtmtlQkMDqok/+LxZTIA Fft8ZXVpiqCJCP8miE5QzIVVR0eJpPs/kLTUgPPTN8npCXvrIHnQywVjXmvpIh5HPIAe Wa7BMy38S7p9H8D/B9xnivP/Ilz8RTzDI0NFXnMY4KF1cUTUopybY81MTIEXSbkQ8k4b +E58TE1QbFn70oHBRkLa8Che+5cPhJvjnPLMHITMfgwQzHhRskF+aYV9mO2sNYi/cltS EV/yZHL9/gfcte5RkSa8/Haz7iYyw4HKPiuISIuf7vrZZhH59ApyKYhy7WYnKkpEF4Va 9sRw== 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:mime-version:content-transfer-encoding; bh=Ce4N/nMYo7+RfxBkmlKo7hExteLUxNUpfT4nrnEM84A=; b=XIwE1N1n8VdxWECVnkKhEqXHeeDQHoNxo46NwAR+jN6gGmfmEK0MaXd84gqhZYnsq+ fH1+BJtQTQmf2dEYdxLnekIIFjUMzsraEuQpl1KgoER+n8cZ+1wK0JlxF2ZxDenqO18z 1ow28zYsa6pKBSOnp6AAQc66533UwgOK7+fyAx3bBVO2CouTOICkXIb7DLyjiAS4qnbL 0kkFThEWwD0elRVF5DtS+6xAm03j0xmQMIuw+7h1P6Iot2118jzfwRCpUKAn9riI1EYf +Sd07dKuschQc/tlK9CJHWowH0G4sonlNv3F67H0yHBkF268nZpW5s/gmQECsTJyDSO8 ZkXw== X-Gm-Message-State: AGRZ1gL/wzDwdQ1Zn2RP7mmiRdtXTOGW+8VY94Kjm/BOdNDPwOP17Z75 StKB6cT1iNTjBZOzOoAULjFbuA== X-Google-Smtp-Source: AJdET5dN2RP29VYyaLlKwxLPMus2CsNsK+huRP1o94zV2LhR/oELAyawrtwYhu4G/QM2rYIsYijVRg== X-Received: by 2002:a1c:d181:: with SMTP id i123-v6mr2789337wmg.124.1541525452833; Tue, 06 Nov 2018 09:30:52 -0800 (PST) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id z17-v6sm16328416wrm.65.2018.11.06.09.30.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 Nov 2018 09:30:52 -0800 (PST) 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 , Vishwath Mohan , Andrey Konovalov Subject: [PATCH v10 07/22] kasan: initialize shadow to 0xff for tag-based mode Date: Tue, 6 Nov 2018 18:30:22 +0100 Message-Id: <9405f32797b52616cd0746bcea37df94e8e4256a.1541525354.git.andreyknvl@google.com> X-Mailer: git-send-email 2.19.1.930.g4563a0d9d0-goog In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org A tag-based KASAN shadow memory cell contains a memory tag, that corresponds to the tag in the top byte of the pointer, that points to that memory. The native top byte value of kernel pointers is 0xff, so with tag-based KASAN we need to initialize shadow memory to 0xff. Reviewed-by: Andrey Ryabinin Reviewed-by: Dmitry Vyukov Signed-off-by: Andrey Konovalov --- arch/arm64/mm/kasan_init.c | 16 ++++++++++++++-- include/linux/kasan.h | 8 ++++++++ mm/kasan/common.c | 3 ++- 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index 63527e585aac..18ebc8994a7b 100644 --- a/arch/arm64/mm/kasan_init.c +++ b/arch/arm64/mm/kasan_init.c @@ -43,6 +43,15 @@ static phys_addr_t __init kasan_alloc_zeroed_page(int node) return __pa(p); } +static phys_addr_t __init kasan_alloc_raw_page(int node) +{ + void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS), + MEMBLOCK_ALLOC_ACCESSIBLE, + node); + return __pa(p); +} + static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early) { @@ -88,7 +97,9 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, do { phys_addr_t page_phys = early ? __pa_symbol(kasan_zero_page) - : kasan_alloc_zeroed_page(node); + : kasan_alloc_raw_page(node); + if (!early) + memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE); next = addr + PAGE_SIZE; set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep))); @@ -138,6 +149,7 @@ asmlinkage void __init kasan_early_init(void) KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); + kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true); } @@ -234,7 +246,7 @@ void __init kasan_init(void) set_pte(&kasan_zero_pte[i], pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO)); - memset(kasan_zero_page, 0, PAGE_SIZE); + memset(kasan_zero_page, KASAN_SHADOW_INIT, PAGE_SIZE); cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); /* At this point kasan is fully initialized. Enable error messages */ diff --git a/include/linux/kasan.h b/include/linux/kasan.h index b66fdf5ea7ab..7f6574c35c62 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -153,6 +153,8 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; } #ifdef CONFIG_KASAN_GENERIC +#define KASAN_SHADOW_INIT 0 + void kasan_cache_shrink(struct kmem_cache *cache); void kasan_cache_shutdown(struct kmem_cache *cache); @@ -163,4 +165,10 @@ static inline void kasan_cache_shutdown(struct kmem_cache *cache) {} #endif /* CONFIG_KASAN_GENERIC */ +#ifdef CONFIG_KASAN_SW_TAGS + +#define KASAN_SHADOW_INIT 0xFF + +#endif /* CONFIG_KASAN_SW_TAGS */ + #endif /* LINUX_KASAN_H */ diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 5f68c93734ba..7134e75447ff 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -473,11 +473,12 @@ int kasan_module_alloc(void *addr, size_t size) ret = __vmalloc_node_range(shadow_size, 1, shadow_start, shadow_start + shadow_size, - GFP_KERNEL | __GFP_ZERO, + GFP_KERNEL, PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, __builtin_return_address(0)); if (ret) { + __memset(ret, KASAN_SHADOW_INIT, shadow_size); find_vm_area(addr)->flags |= VM_KASAN; kmemleak_ignore(ret); return 0; -- 2.19.1.930.g4563a0d9d0-goog