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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6EA6DC7618A for ; Wed, 15 Mar 2023 20:58:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pcYBw-0001W9-UU; Wed, 15 Mar 2023 16:57:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pcYBv-0001SN-2e for qemu-devel@nongnu.org; Wed, 15 Mar 2023 16:57:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pcYBt-00024Q-En for qemu-devel@nongnu.org; Wed, 15 Mar 2023 16:57:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678913864; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=Su35NByslQ7vkyq8AYJmNhwF8Dawa03AgWtziG6uyVo=; b=hL3Bzk0nOiexvbWyS5iltY2r8ixyBf+5pSdP0abrpMIBOe94D33YIe1sBvW4l8OBdsZ9iJ iINjyyU+LZ260w9x0IcelNv8vjvON3B/VDl3BkSWS+Nce+knk6Ped5XP9GLvuijnBat+qR uzVSrPQjrn00rbNZ72YXmSRFlcqFmd8= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-346-32lqcqUbONqc5HyleNfdHw-1; Wed, 15 Mar 2023 16:57:43 -0400 X-MC-Unique: 32lqcqUbONqc5HyleNfdHw-1 Received: by mail-wm1-f70.google.com with SMTP id bd26-20020a05600c1f1a00b003ed23f09060so1205027wmb.3 for ; Wed, 15 Mar 2023 13:57:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678913861; h=mime-version:message-id:date:reply-to:user-agent:references :in-reply-to:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Su35NByslQ7vkyq8AYJmNhwF8Dawa03AgWtziG6uyVo=; b=Ep5ijMnCXnCkGQhZG7Z3mzIgcXbO31LIPdCvZf8b8ZzzoOOKj3B3kZKST3R5rTHy2W GbrY+b2E7YLHe8LTpT1jnuwiKPkGBXRs/B8/5KcHK2epxRNKJyVHERXOeAXCLaTvOgpe RHXuQN2mNB7ibu/ceml9iPCwfY4PRhXqeSkXHCFwWnpzUj68H/wQFxxoslOyxzHfEiTp wgGUpHxdRVB5NjuFEdZSCGnkd8Qse83xSYw6/YVi5RPXlOplWZSa57zmlnTm5XtVV88v KZ+hLKeeKii9HlaMa+M4oL3pD2tGL4a1lY9s+qgXxLTff30FidVszBNdw3s8bJo7ipzY hFGQ== X-Gm-Message-State: AO0yUKUdAh/qRohiLlytBDT3ZT7aFp4olTmxVSDabwsSB8DIxVNsesgh Amlzexb1+ZhQAyOqxBPZxLjjCKqZisIQTK3QvOF/oqDWnKhIn5S2MzEn3UzXMQLjpGDCiev2NKg MCLbr41HSYtYptxE= X-Received: by 2002:a05:600c:470e:b0:3eb:29fe:734a with SMTP id v14-20020a05600c470e00b003eb29fe734amr19253221wmo.39.1678913861693; Wed, 15 Mar 2023 13:57:41 -0700 (PDT) X-Google-Smtp-Source: AK7set8/iOZwpgaY7VV5NavLetCjB4c1CGtkF7kIg8eoZxX1ociaUKGDtP/D5laPdGPzLfr9Ok/9Ag== X-Received: by 2002:a05:600c:470e:b0:3eb:29fe:734a with SMTP id v14-20020a05600c470e00b003eb29fe734amr19253208wmo.39.1678913861340; Wed, 15 Mar 2023 13:57:41 -0700 (PDT) Received: from redhat.com (62.117.238.225.dyn.user.ono.com. [62.117.238.225]) by smtp.gmail.com with ESMTPSA id u18-20020a5d4352000000b002d1daafea30sm222364wrr.34.2023.03.15.13.57.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Mar 2023 13:57:40 -0700 (PDT) From: Juan Quintela To: Matheus Tavares Bernardino Cc: , , , , , Subject: Re: [PATCH RESEND v2 2/2] migration/xbzrle: fix out-of-bounds write with axv512 In-Reply-To: <08a655a31d3161e76c4fceaf43e8960e751cdf87.1678733663.git.quic_mathbern@quicinc.com> (Matheus Tavares Bernardino's message of "Mon, 13 Mar 2023 15:58:20 -0300") References: <08a655a31d3161e76c4fceaf43e8960e751cdf87.1678733663.git.quic_mathbern@quicinc.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Date: Wed, 15 Mar 2023 21:57:40 +0100 Message-ID: <87pm99n35n.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=170.10.133.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Matheus Tavares Bernardino wrote: > xbzrle_encode_buffer_avx512() checks for overflows too scarcely in its > outer loop, causing out-of-bounds writes: > > $ ../configure --target-list=aarch64-softmmu --enable-sanitizers --enable-avx512bw > $ make tests/unit/test-xbzrle && ./tests/unit/test-xbzrle > > ==5518==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62100000b100 at pc 0x561109a7714d bp 0x7ffed712a440 sp 0x7ffed712a430 > WRITE of size 1 at 0x62100000b100 thread T0 > #0 0x561109a7714c in uleb128_encode_small ../util/cutils.c:831 > #1 0x561109b67f6a in xbzrle_encode_buffer_avx512 ../migration/xbzrle.c:275 > #2 0x5611099a7428 in test_encode_decode_overflow ../tests/unit/test-xbzrle.c:153 > #3 0x7fb2fb65a58d (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7a58d) > #4 0x7fb2fb65a333 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7a333) > #5 0x7fb2fb65aa79 in g_test_run_suite (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7aa79) > #6 0x7fb2fb65aa94 in g_test_run (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7aa94) > #7 0x5611099a3a23 in main ../tests/unit/test-xbzrle.c:218 > #8 0x7fb2fa78c082 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24082) > #9 0x5611099a608d in _start (/qemu/build/tests/unit/test-xbzrle+0x28408d) > > 0x62100000b100 is located 0 bytes to the right of 4096-byte region [0x62100000a100,0x62100000b100) > allocated by thread T0 here: > #0 0x7fb2fb823a06 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:153 > #1 0x7fb2fb637ef0 in g_malloc0 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x57ef0) > > Fix that by performing the overflow check in the inner loop, instead. > > Signed-off-by: Matheus Tavares Bernardino Reviewed-by: Juan Quintela queued. As David said, we can still improve the code. thanks, Juan.