From nobody Fri Sep 20 10:01:07 2024 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37E8FEDE98C for ; Thu, 14 Sep 2023 08:08:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236223AbjINIIr (ORCPT ); Thu, 14 Sep 2023 04:08:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229890AbjINIIq (ORCPT ); Thu, 14 Sep 2023 04:08:46 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E57AF9B for ; Thu, 14 Sep 2023 01:08:41 -0700 (PDT) X-UUID: e7bd0d1252d511eea33bb35ae8d461a2-20230914 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=mlOEeXuSL3Jd9KWoAGMasqY7uUX1ru96a24IVEsPgXk=; b=nbN5kH2ZHeBSmRDbusxGl/9eZ7H7OM8VxEjN4Ceca7hkyiE0CFGeQkeuunWg5eIxbwkPkmeufwzTexRgUinXlwQ7jnxFzPWvyYuJLwqC/Lu3A8Lec/y8ZBCSLi0HkNR5XSRzUt5nmpMC2GJwBAABc2a32vq8tNsraXzIPxgHiVg=; X-CID-CACHE: Type:Local,Time:202309141550+08,HitQuantity:1 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.31,REQID:e318bec8-4d6f-4264-ad9c-b8bfbcc41368,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:0ad78a4,CLOUDID:228104c3-1e57-4345-9d31-31ad9818b39f,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:11|1,File:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1,SPR: NO,DKR:0,DKP:0,BRR:0,BRE:0 X-CID-BVR: 0,NGT X-CID-BAS: 0,NGT,0,_ X-CID-FACTOR: TF_CID_SPAM_ULN,TF_CID_SPAM_SNR X-UUID: e7bd0d1252d511eea33bb35ae8d461a2-20230914 Received: from mtkmbs13n2.mediatek.inc [(172.21.101.108)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1145535570; Thu, 14 Sep 2023 16:08:36 +0800 Received: from mtkmbs13n1.mediatek.inc (172.21.101.193) by mtkmbs11n1.mediatek.inc (172.21.101.185) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Thu, 14 Sep 2023 16:08:35 +0800 Received: from mszsdtlt101.gcn.mediatek.inc (10.16.4.141) by mtkmbs13n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Thu, 14 Sep 2023 16:08:34 +0800 From: Haibo Li To: CC: , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Matthias Brugger , AngeloGioacchino Del Regno , , , , , Haibo Li Subject: [PATCH] kasan:fix access invalid shadow address when input is illegal Date: Thu, 14 Sep 2023 16:08:33 +0800 Message-ID: <20230914080833.50026-1-haibo.li@mediatek.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" when the input address is illegal,the corresponding shadow address from kasan_mem_to_shadow may have no mapping in mmu table. Access such shadow address causes kernel oops. Here is a sample about oops on arm64(VA 39bit) with KASAN_SW_TAGS on: [ffffffb80aaaaaaa] pgd=3D000000005d3ce003, p4d=3D000000005d3ce003, pud=3D000000005d3ce003, pmd=3D0000000000000000 Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP Modules linked in: CPU: 3 PID: 100 Comm: sh Not tainted 6.6.0-rc1-dirty #43 Hardware name: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : __hwasan_load8_noabort+0x5c/0x90 lr : do_ib_ob+0xf4/0x110 ffffffb80aaaaaaa is the shadow address for efffff80aaaaaaaa. The problem is reading invalid shadow in kasan_check_range. The generic kasan also has similar oops. To fix it,check shadow address by reading it with no fault. After this patch,KASAN is able to report invalid memory access for this case. Signed-off-by: Haibo Li --- mm/kasan/kasan.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index f70e3d7a602e..bd30f35e18b2 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -304,8 +304,17 @@ static __always_inline bool addr_has_metadata(const vo= id *addr) #ifdef __HAVE_ARCH_SHADOW_MAP return (kasan_mem_to_shadow((void *)addr) !=3D NULL); #else - return (kasan_reset_tag(addr) >=3D - kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); + u8 *shadow, shadow_val; + + if (kasan_reset_tag(addr) < + kasan_shadow_to_mem((void *)KASAN_SHADOW_START)) + return false; + /* use read with nofault to check whether the shadow is accessible */ + shadow =3D kasan_mem_to_shadow((void *)addr); + __get_kernel_nofault(&shadow_val, shadow, u8, fault); + return true; +fault: + return false; #endif } =20 --=20 2.25.1