From patchwork Fri Jul 2 08:54:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?WWVlIExlZSAo5p2O5bu66Kq8KQ==?= X-Patchwork-Id: 12355665 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=-17.0 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,MIME_BASE64_TEXT,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 D84D1C11F68 for ; Fri, 2 Jul 2021 09:04:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 53D2E613D2 for ; Fri, 2 Jul 2021 09:04:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53D2E613D2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D44C86B0011; Fri, 2 Jul 2021 05:04:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CF5266B0036; Fri, 2 Jul 2021 05:04:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B94EF6B005D; Fri, 2 Jul 2021 05:04:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 905766B0011 for ; Fri, 2 Jul 2021 05:04:41 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 3DB3D18210E9D for ; Fri, 2 Jul 2021 09:04:41 +0000 (UTC) X-FDA: 78317062362.24.77F7FEB Received: from mailgw02.mediatek.com (mailgw02.mediatek.com [216.200.240.185]) by imf12.hostedemail.com (Postfix) with ESMTP id 9086110000A5 for ; Fri, 2 Jul 2021 09:04:38 +0000 (UTC) X-UUID: fa44e7d3392143bb8bbc76109573e72b-20210702 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=lTIa33kb1s532t1Ijy/qXL69Ig/qhCVNWPSqayMKIv0=; b=ChLWC/kvCfsBcszcaXZ2f/7vd97S4Klm8x15CHQCmd+OYczTweKLjzSSb3Zh3aeRXHVbHI0+zWQHNWxXTyFMvXSqlW5xJtDdj3XvdPvWG47yK/vEoPrpocE4K6KjOwNgL2LIcozCfaRD6sIEn8xUbbQtX5HI5E3oA0NGqHbk27g=; X-UUID: fa44e7d3392143bb8bbc76109573e72b-20210702 Received: from mtkcas66.mediatek.inc [(172.29.193.44)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 354993285; Fri, 02 Jul 2021 02:04:29 -0700 Received: from MTKMBS02N2.mediatek.inc (172.21.101.101) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 2 Jul 2021 01:54:27 -0700 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 2 Jul 2021 16:54:26 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 2 Jul 2021 16:54:26 +0800 From: To: CC: , , , , Yee Lee , Andrey Ryabinin , "Alexander Potapenko" , Dmitry Vyukov , "Andrew Morton" , Matthias Brugger , "open list:KASAN" , "open list:MEMORY MANAGEMENT" , open list , "moderated list:ARM/Mediatek SoC support" , "moderated list:ARM/Mediatek SoC support" Subject: [PATCH v4 2/2] kasan: Add memzero int for unaligned size at DEBUG Date: Fri, 2 Jul 2021 16:54:22 +0800 Message-ID: <20210702085422.10092-1-yee.lee@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-MTK: N X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9086110000A5 X-Stat-Signature: jsanerdq7y1zxoig85g3gpc9rh7u4jm1 Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=mediatek.com header.s=dk header.b="ChLWC/kv"; dmarc=pass (policy=none) header.from=mediatek.com; spf=pass (imf12.hostedemail.com: domain of yee.lee@mediatek.com designates 216.200.240.185 as permitted sender) smtp.mailfrom=yee.lee@mediatek.com X-HE-Tag: 1625216678-20692 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: Yee Lee Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite the redzone of object with unaligned size. An additional memzero_explicit() path is added to replacing init by hwtag instruction for those unaligned size at SLUB debug mode. The penalty is acceptable since they are only enabled in debug mode, not production builds. A block of comment is added for explanation. --- v4: - Add "slab.h" header - Use slub_debug_enabled_unlikely() to replace IS_ENABLED - Refine the comment block --- Signed-off-by: Yee Lee Suggested-by: Marco Elver Suggested-by: Andrey Konovalov Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrew Morton --- mm/kasan/kasan.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 98e3059bfea4..a9d837197302 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -9,6 +9,7 @@ #ifdef CONFIG_KASAN_HW_TAGS #include +#include "../slab.h" DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace); extern bool kasan_flag_async __ro_after_init; @@ -387,6 +388,17 @@ static inline void kasan_unpoison(const void *addr, size_t size, bool init) if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK)) return; + /* + * Explicitly initialize the memory with the precise object size to + * avoid overwriting the SLAB redzone. This disables initialization in + * the arch code and may thus lead to performance penalty. The penalty + * is accepted since SLAB redzones aren't enabled in production builds. + */ + if (slub_debug_enabled_unlikely() && + init && ((unsigned long)size & KASAN_GRANULE_MASK)) { + init = false; + memzero_explicit((void *)addr, size); + } size = round_up(size, KASAN_GRANULE_SIZE); hw_set_mem_tag_range((void *)addr, size, tag, init);