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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 F3C6BC11F65 for ; Tue, 29 Jun 2021 02:40:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A5FE261D0E for ; Tue, 29 Jun 2021 02:40:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A5FE261D0E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0A4C28D0103; Mon, 28 Jun 2021 22:40:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 054AA8D00F0; Mon, 28 Jun 2021 22:40:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E85918D0103; Mon, 28 Jun 2021 22:40:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id C0A858D00F0 for ; Mon, 28 Jun 2021 22:40:44 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C2E358249980 for ; Tue, 29 Jun 2021 02:40:44 +0000 (UTC) X-FDA: 78305208408.30.D2FE996 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf06.hostedemail.com (Postfix) with ESMTP id 73817C01C082 for ; Tue, 29 Jun 2021 02:40:44 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 547CD61D0D; Tue, 29 Jun 2021 02:40:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1624934443; bh=chNl3OCjqTBl20F7uY2WGVVKn2YAun0nlvwdNu/80Is=; h=Date:From:To:Subject:In-Reply-To:From; b=kQv4cOonYJKL5ydzAn96AETfyWDjCcrt3hluifyCUwAr+4NQhzT/JJWS6Q7mObD3c j973bWmWtlRlB+7J9U2pH0RmxSk9iNbYgHmKCNzgHfvsoOrJBAufBLOQwco6VtdIy8 zFonIypg99B0X5UVlxbDlF4wAKTef3y06Ekp6Wx0= Date: Mon, 28 Jun 2021 19:40:42 -0700 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@gmail.com, aneesh.kumar@linux.ibm.com, bsingharora@gmail.com, christophe.leroy@csgroup.eu, dja@axtens.net, dvyukov@google.com, elver@google.com, glider@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, ryabinin.a.a@gmail.com, torvalds@linux-foundation.org Subject: [patch 142/192] kasan: allow architectures to provide an outline readiness check Message-ID: <20210629024042.WmBRY3Eet%akpm@linux-foundation.org> In-Reply-To: <20210628193256.008961950a714730751c1423@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=kQv4cOon; dmarc=none; spf=pass (imf06.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Stat-Signature: jhsu3xjgm8wxdpikwkay5yy4wcg5spm9 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 73817C01C082 X-HE-Tag: 1624934444-608323 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: From: Daniel Axtens Subject: kasan: allow architectures to provide an outline readiness check Allow architectures to define a kasan_arch_is_ready() hook that bails out of any function that's about to touch the shadow unless the arch says that it is ready for the memory to be accessed. This is fairly uninvasive and should have a negligible performance penalty. This will only work in outline mode, so an arch must specify ARCH_DISABLE_KASAN_INLINE if it requires this. Link: https://lkml.kernel.org/r/20210624034050.511391-3-dja@axtens.net Signed-off-by: Daniel Axtens Reviewed-by: Marco Elver Suggested-by: Christophe Leroy Reviewed-by: Andrey Konovalov Cc: Balbir Singh Cc: Aneesh Kumar K.V Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Signed-off-by: Andrew Morton --- mm/kasan/common.c | 3 +++ mm/kasan/generic.c | 3 +++ mm/kasan/kasan.h | 6 ++++++ mm/kasan/shadow.c | 6 ++++++ 4 files changed, 18 insertions(+) --- a/mm/kasan/common.c~kasan-allow-architectures-to-provide-an-outline-readiness-check +++ a/mm/kasan/common.c @@ -331,6 +331,9 @@ static inline bool ____kasan_slab_free(s u8 tag; void *tagged_object; + if (!kasan_arch_is_ready()) + return false; + tag = get_tag(object); tagged_object = object; object = kasan_reset_tag(object); --- a/mm/kasan/generic.c~kasan-allow-architectures-to-provide-an-outline-readiness-check +++ a/mm/kasan/generic.c @@ -163,6 +163,9 @@ static __always_inline bool check_region size_t size, bool write, unsigned long ret_ip) { + if (!kasan_arch_is_ready()) + return true; + if (unlikely(size == 0)) return true; --- a/mm/kasan/kasan.h~kasan-allow-architectures-to-provide-an-outline-readiness-check +++ a/mm/kasan/kasan.h @@ -449,6 +449,12 @@ static inline void kasan_poison_last_gra #endif /* CONFIG_KASAN_GENERIC */ +#ifndef kasan_arch_is_ready +static inline bool kasan_arch_is_ready(void) { return true; } +#elif !defined(CONFIG_KASAN_GENERIC) || !defined(CONFIG_KASAN_OUTLINE) +#error kasan_arch_is_ready only works in KASAN generic outline mode! +#endif + /* * Exported functions for interfaces called from assembly or from generated * code. Declarations here to avoid warning about missing declarations. --- a/mm/kasan/shadow.c~kasan-allow-architectures-to-provide-an-outline-readiness-check +++ a/mm/kasan/shadow.c @@ -73,6 +73,9 @@ void kasan_poison(const void *addr, size { void *shadow_start, *shadow_end; + if (!kasan_arch_is_ready()) + return; + /* * Perform shadow offset calculation based on untagged address, as * some of the callers (e.g. kasan_poison_object_data) pass tagged @@ -99,6 +102,9 @@ EXPORT_SYMBOL(kasan_poison); #ifdef CONFIG_KASAN_GENERIC void kasan_poison_last_granule(const void *addr, size_t size) { + if (!kasan_arch_is_ready()) + return; + if (size & KASAN_GRANULE_MASK) { u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size); *shadow = size & KASAN_GRANULE_MASK; _