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=-15.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C8044C433F5 for ; Fri, 3 Sep 2021 21:16:27 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 74D7560184 for ; Fri, 3 Sep 2021 21:16:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 74D7560184 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:38224 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mMGXy-0007jy-JY for qemu-devel@archiver.kernel.org; Fri, 03 Sep 2021 17:16:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59576) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mMGVN-0003Hs-Nt for qemu-devel@nongnu.org; Fri, 03 Sep 2021 17:13:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:21991) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mMGVM-0002iS-2l for qemu-devel@nongnu.org; Fri, 03 Sep 2021 17:13:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630703623; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/d4C/QbXJZGAaDLSeN+s4CWc2iWOHgX8c+5IR1zVWgc=; b=a3RoiLk30gv9S53q0+vpyW9SMdE7evtDb95IXPPb4HbhFw9EFY6XoIiX1H4ANJsWho3mLB nl0yC9+QclTGk+wXVTBgVZZwtVPappEuQZUa7AER30zIPIQPof6GTzM2XUwF3egkxVftxb UPJPxv/0miGGhuSYIYe20zPsknMn/0I= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-249-EGpLn-XqPvuZx1yawfyxpA-1; Fri, 03 Sep 2021 17:13:42 -0400 X-MC-Unique: EGpLn-XqPvuZx1yawfyxpA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A71B4100945A; Fri, 3 Sep 2021 21:13:40 +0000 (UTC) Received: from redhat.com (ovpn-113-81.phx2.redhat.com [10.3.113.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EB4E55D9F0; Fri, 3 Sep 2021 21:13:28 +0000 (UTC) Date: Fri, 3 Sep 2021 16:13:22 -0500 From: Eric Blake To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v3 05/28] block/qcow2-bitmap: Replace g_memdup() by g_memdup2() Message-ID: <20210903211322.n5isnkxin6jlkxrf@redhat.com> References: <20210903174510.751630-1-philmd@redhat.com> <20210903174510.751630-6-philmd@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210903174510.751630-6-philmd@redhat.com> User-Agent: NeoMutt/20210205-739-420e15 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.392, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , "Michael S. Tsirkin" , Jason Wang , Christian Schoenebeck , qemu-devel@nongnu.org, Gerd Hoffmann , qemu-block@nongnu.org, John Snow , David Hildenbrand , Markus Armbruster , Laurent Vivier , Thomas Huth , Eduardo Habkost , Richard Henderson , qemu-arm@nongnu.org, Alex =?utf-8?Q?Benn=C3=A9e?= , David Gibson , Kevin Wolf , Vladimir Sementsov-Ogievskiy , "Daniel P . Berrange" , Hanna Reitz , qemu-ppc@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Sep 03, 2021 at 07:44:47PM +0200, Philippe Mathieu-Daudé wrote: > Per https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538 > > The old API took the size of the memory to duplicate as a guint, > whereas most memory functions take memory sizes as a gsize. This > made it easy to accidentally pass a gsize to g_memdup(). For large > values, that would lead to a silent truncation of the size from 64 > to 32 bits, and result in a heap area being returned which is > significantly smaller than what the caller expects. This can likely > be exploited in various modules to cause a heap buffer overflow. > > Replace g_memdup() by the safer g_memdup2() wrapper. > > Signed-off-by: Philippe Mathieu-Daudé > --- > block/qcow2-bitmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c > index 8fb47315515..218a0dc712a 100644 > --- a/block/qcow2-bitmap.c > +++ b/block/qcow2-bitmap.c > @@ -1599,7 +1599,7 @@ bool qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, > name); > goto fail; > } > - tb = g_memdup(&bm->table, sizeof(bm->table)); > + tb = g_memdup2(&bm->table, sizeof(bm->table)); Trivially safe. It might be worth a comment in the various commit messages for which patches are trivially safe (because the argument was directly from sizeof), and which would require a larger audit of callers to see if we had any (unlikely) bug (such as patch 3/28). Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org