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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no 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 B86B2C4360C for ; Tue, 8 Oct 2019 12:11:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 79D172070B for ; Tue, 8 Oct 2019 12:11:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eh8pCLow" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79D172070B Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F24E68E0005; Tue, 8 Oct 2019 08:11:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ED57B8E0003; Tue, 8 Oct 2019 08:11:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DEB9F8E0005; Tue, 8 Oct 2019 08:11:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0126.hostedemail.com [216.40.44.126]) by kanga.kvack.org (Postfix) with ESMTP id BDB6C8E0003 for ; Tue, 8 Oct 2019 08:11:37 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 59F25824CA2D for ; Tue, 8 Oct 2019 12:11:37 +0000 (UTC) X-FDA: 76020503034.05.mice87_6552a07a2ba14 X-HE-Tag: mice87_6552a07a2ba14 X-Filterd-Recvd-Size: 3712 Received: from mail-qk1-f196.google.com (mail-qk1-f196.google.com [209.85.222.196]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 12:11:36 +0000 (UTC) Received: by mail-qk1-f196.google.com with SMTP id u186so16449567qkc.5 for ; Tue, 08 Oct 2019 05:11:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GMN6AE/Wckiy15zsiQVxc8Ha0nqrOTJmAoLEeM+N80A=; b=eh8pCLowBh+BgvZfmBoGRvtXPz9zE1aDs0RO30fbYsKrn8CCi0iz7dLb+5ZAUaoxjI h8+YdOrv4kFWisVv0+ypSez27VEQps+efiGk7jOMYv3keDR/Y6/soCbxUzNbJXsWmunL vpPylf8BdgPE/ZA1QeOokTinVOQWJUymEUANn2Y+dJMoeBbgBazYB8JxeoNrYQwBHkLP +Y93UIITl3fYH+rqskwFY4S7s0OHFw4upx8Nhqyxd6tVP1iDJRTOXsPTSYokzso/fTTr QdOgkswn28Rv8/n9whT/owI7R/u5774xcNIdbtAtjI/OLjhmtMk6lPra8liDCk+ffMra +nBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=GMN6AE/Wckiy15zsiQVxc8Ha0nqrOTJmAoLEeM+N80A=; b=hlIxhVOs3aQgL2Wb7+cVs5xGiISbr9FuiNa3sG9mNXp3zVqg4qHmO/zXa+SUpFt+EG UiYDXkpTVqcEzhsze8Cos8yDqLSDft8R0KyY7i8M+fEbnFvv7+rRw/JJExG/tXm4/icq mEB6EV+hea9oqKAEa0pSxiyy8f95cr2my8RudKch1ElGlxRFeWxheUkCjhrW3+ANFGJk EcrF2B1k1auk53CuGsW0HNyqKxBEYZFUbXeQDFZISoy3SYrjyRYI1dqkoH4egTqhkYYV OIayWU6eTLoVj/3JspzyMLlEls5qj1gInHmPx/lZDx3VeuKiLkT8CEsCDuIP86s8MlaE vC7Q== X-Gm-Message-State: APjAAAUW0NY7OIm2ZQmQZuILDmTfmrS2CBQB0aVuffKVXRYJrwbmj2h7 3CwEP9Fulgmv1PnyKRAb4opFeQDUE9jtrnmiMx3Qew== X-Google-Smtp-Source: APXvYqyJTh5B6y0iJNFqTbgDhKIdXD1dXKap90/51GY/1HBwwtMG0+QVGVvei9Jaj15xHEza/1jKSqBJZkqQ4s2WLQ0= X-Received: by 2002:a37:d84:: with SMTP id 126mr26540903qkn.407.1570536695225; Tue, 08 Oct 2019 05:11:35 -0700 (PDT) MIME-Version: 1.0 References: <1570532528.4686.102.camel@mtksdccf07> In-Reply-To: From: Dmitry Vyukov Date: Tue, 8 Oct 2019 14:11:23 +0200 Message-ID: Subject: Re: [PATCH] kasan: fix the missing underflow in memmove and memcpy with CONFIG_KASAN_GENERIC=y To: Qian Cai Cc: Walter Wu , Andrey Ryabinin , Alexander Potapenko , Matthias Brugger , LKML , kasan-dev , Linux-MM , Linux ARM , linux-mediatek@lists.infradead.org, wsd_upstream Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.013242, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 8, 2019 at 1:42 PM Qian Cai wrote: > > On Oct 8, 2019, at 7:02 AM, Walter Wu wrote: > > I don't know very well in UBSAN, but I try to build ubsan kernel and > > test a negative number in memset and kmalloc_memmove_invalid_size(), it > > look like no check. > > It sounds like more important to figure out why the UBSAN is not working in this case rather than duplicating functionality elsewhere. Detecting out-of-bounds accesses is the direct KASAN responsibility. Even more direct than for KUBSAN. We are not even adding functionality, it's just a plain bug in KASAN code, it tricks itself into thinking that access size is 0. Maybe it's already detected by KUBSAN too?