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=-13.6 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 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 D8CFDC433E0 for ; Mon, 18 Jan 2021 12:40:33 +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 508502231F for ; Mon, 18 Jan 2021 12:40:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 508502231F Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=nongnu.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43250 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l1Tpg-0006Yd-5n for qemu-devel@archiver.kernel.org; Mon, 18 Jan 2021 07:40:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48038) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l1Tka-0002Nx-VY for qemu-devel@nongnu.org; Mon, 18 Jan 2021 07:35:18 -0500 Received: from kylie.crudebyte.com ([5.189.157.229]:59141) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l1TkM-0003f2-KI for qemu-devel@nongnu.org; Mon, 18 Jan 2021 07:35:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=OfMXaioHYWngjNIBi8eXl3N7DH/iwcVsdI4WLDaqFQ8=; b=vXuOYiRlsWWRE7jd5YhheyuLMK 4u510SAfGzprySW8Wr6OExh4fXEaYnSTSm2c1jJ71ZkSMDt/38wK3WlPLaYaHcRlLzaUbsm8FfeRx uBEReHDBvGNPFd6o1xcKqQjPCHaREs8MbSCzf+lRSNqWsz0lsJmdsd0sgiRUvWCZbVuL33P24T+DM ool5LDSFGv4SuxPxNNPJG1nRYgj0st3Hp+biCwSTP7ajZSQqWxGjc9spqbjOcYdQWX8M5hK4wZmI3 kjVNvuqigAy97r2fRkggLbH6tTXAU8NS69npm053+SFTVzeZLtshO4oLLfBXHlAhdiA28qFTXmHUm T5bW2nN/VCtPVfVAwidmEDVd2r/7RNd8J5CRz6+cBFFrKp9Pt+ZdpJNbexXHtOk1WOTm8o4EkawSS VCQY3g5YrTaFOvkS09k9fziAVg8ykpaWSNejOQ48bqKuJASd1GYxYS+Tzzt0orzXYNOZLJHJ5t/T4 j+iHL0adcHGKgTt/F488D4yIR+tJsTv8hnwDlC/2O25wwZnEPm8TLXJSfDiPJ0UMvNLEyJu64yNh9 YNr1MNwdl+/LX7YRd7GVwhegL4beoTEWGfSE3wB7mok2XaTOKJs60rYP+MKofA0f82IoK3hUnS3xx KPBvIo1K+Dv54HzJdq5mBxGcI96nQpLVFXihrbpVs=; To: qemu-devel@nongnu.org Subject: Re: [PATCH v2 3/3] fuzz: add virtio-9p configurations for fuzzing Date: Mon, 18 Jan 2021 13:34:32 +0100 Message-ID: <23015364.U02QJlgKXI@silver> In-Reply-To: <20210117230924.449676-4-alxndr@bu.edu> References: <20210117230924.449676-1-alxndr@bu.edu> <20210117230924.449676-4-alxndr@bu.edu> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Received-SPF: pass client-ip=5.189.157.229; envelope-from=qemu_oss@crudebyte.com; helo=kylie.crudebyte.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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: Laurent Vivier , Thomas Huth , Greg Kurz , Alexander Bulekov , Bandan Das , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reply-to: Christian Schoenebeck From: qemu_oss--- via On Montag, 18. Januar 2021 00:09:24 CET Alexander Bulekov wrote: > virtio-9p devices are often used to expose a virtual-filesystem to the > guest. There have been some bugs reported in this device, such as > CVE-2018-19364, and CVE-2021-20181. We should fuzz this device > > This patch adds two virtio-9p configurations: > * One with the widely used -fsdev local driver. This driver leaks some > state in the form of files/directories created in the shared dir. > * One with the synth driver. While it is not used in the real world, this > driver won't leak leak state between fuzz inputs. > > Signed-off-by: Alexander Bulekov > --- > CC: Christian Schoenebeck > CC: Greg Kurz > > I considered adding an atexit handler to remove the temp directory, > however I am worried that there might be some error that results in a > call to exit(), rather than abort(), which will cause problems for > future fork()-ed fuzzers. I don't think there are such calls in the 9p > code, however there might be something in the APIs used by 9p. As this > code is primarily for ephemeral OSS-Fuzz conainers, this shouldn't be > too much of an issue. Yes, dealing with signal handlers for that is probably a bit intransparent and would leave a questionable feeling about its reliability. What about __attribute__((destructor)) to auto delete the fuzzer directory, like virtio-9p-test.c does for the same task? > tests/qtest/fuzz/generic_fuzz_configs.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/tests/qtest/fuzz/generic_fuzz_configs.h > b/tests/qtest/fuzz/generic_fuzz_configs.h index 1a133655ee..f99657cdbc > 100644 > --- a/tests/qtest/fuzz/generic_fuzz_configs.h > +++ b/tests/qtest/fuzz/generic_fuzz_configs.h > @@ -19,6 +19,16 @@ typedef struct generic_fuzz_config { > gchar* (*argfunc)(void); /* Result must be freeable by g_free() */ > } generic_fuzz_config; > > +static inline gchar *generic_fuzzer_virtio_9p_args(void){ > + char tmpdir[] = "/tmp/qemu-fuzz.XXXXXX"; > + g_assert_nonnull(mkdtemp(tmpdir)); > + > + return g_strdup_printf("-machine q35 -nodefaults " > + "-device virtio-9p,fsdev=hshare,mount_tag=hshare " > + "-fsdev local,id=hshare,path=%s,security_model=mapped-xattr," > + "writeout=immediate,fmode=0600,dmode=0700", tmpdir); > +} > + > const generic_fuzz_config predefined_configs[] = { > { > .name = "virtio-net-pci-slirp", > @@ -60,6 +70,16 @@ const generic_fuzz_config predefined_configs[] = { > .name = "virtio-mouse", > .args = "-machine q35 -nodefaults -device virtio-mouse", > .objects = "virtio*", > + },{ > + .name = "virtio-9p", > + .argfunc = generic_fuzzer_virtio_9p_args, > + .objects = "virtio*", > + },{ > + .name = "virtio-9p-synth", > + .args = "-machine q35 -nodefaults " > + "-device virtio-9p,fsdev=hshare,mount_tag=hshare " > + "-fsdev synth,id=hshare", > + .objects = "virtio*", > },{ > .name = "e1000", > .args = "-M q35 -nodefaults "