From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from forward501p.mail.yandex.net (forward501p.mail.yandex.net [77.88.28.111]) by sourceware.org (Postfix) with ESMTPS id 2106C388451F for ; Fri, 18 Mar 2022 07:26:20 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2106C388451F Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=ya.ru Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=ya.ru Received: from iva6-f97209bf53c9.qloud-c.yandex.net (iva6-f97209bf53c9.qloud-c.yandex.net [IPv6:2a02:6b8:c0c:611f:0:640:f972:9bf]) by forward501p.mail.yandex.net (Yandex) with ESMTP id 2472E6212AB9; Fri, 18 Mar 2022 10:26:18 +0300 (MSK) Received: from iva5-057a0d1fbbd8.qloud-c.yandex.net (iva5-057a0d1fbbd8.qloud-c.yandex.net [2a02:6b8:c0c:7f1c:0:640:57a:d1f]) by iva6-f97209bf53c9.qloud-c.yandex.net (mxback/Yandex) with ESMTP id d6o4cf5Iud-QHeWAxI3; Fri, 18 Mar 2022 10:26:18 +0300 X-Yandex-Fwd: 2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ya.ru; s=mail; t=1647588378; bh=SsxxZjWsvSg57fZvsqRmTwG5gb804EO+yoM/S0DIVDU=; h=References:Date:In-Reply-To:Subject:Cc:From:Message-Id:To; b=K2nzveizfwWBE/TKbUpVNILbrWctoA+2FuU+dVVzG+LR1CezhmElCxmb4FAamw0CC Qj6R5QJLgEURMlH58aK0CJvv8niUHyvT7og5CmGvvTxCvt9eXVzF8+VS3uTcoWIbcS w131JlXhH0iNupWDBCrk05qhLB1UBkW9sBD/CkUY= Authentication-Results: iva6-f97209bf53c9.qloud-c.yandex.net; dkim=pass header.i=@ya.ru Received: by iva5-057a0d1fbbd8.qloud-c.yandex.net (smtp/Yandex) with ESMTPSA id MvmX0eitCo-QHKSIgvi; Fri, 18 Mar 2022 10:26:17 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\)) Subject: Re: Some fuzzer workarounds From: Evgeny Vereshchagin In-Reply-To: <20220317133051.100876-1-mark@klomp.org> Date: Fri, 18 Mar 2022 10:26:16 +0300 Cc: elfutils-devel@sourceware.org, david korczynski Content-Transfer-Encoding: quoted-printable Message-Id: <741FAE40-F8E9-4DA7-A160-E30A76210AC8@ya.ru> References: <20220317133051.100876-1-mark@klomp.org> To: Mark Wielaard X-Mailer: Apple Mail (2.3445.104.21) X-Spam-Status: No, score=-3.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, TXREP, T_SCC_BODY_TEXT_LINE, T_SPF_TEMPERROR autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2022 07:26:25 -0000 Hi, > I looked over the "ClusterFuzz-External via monorail" emails and found > some "real" issues. Given that the new fuzz targets seem to just fail to compile with ``` projects/elfutils/fuzz-libdwfl.c:48:10: error: unused variable 'res' = [-Werror,-Wunused-variable] Dwarf *res =3D dwfl_module_getdwarf(mod, &bias); ^ 1 error generated. ``` I think before looking at those reports it would make sense to figure = out what they are supposed to test and how they were tested to make sure they don't produce false = positives. If they weren't actually tested I think it would make sense to revert them to = avoid getting auto-generated CVEs until they're in more or less good shape at least. > There are also some other > misaligned type access checks reported by ubsan, but I don't know if > that is because of ALLOW_UNALIGNED is still defined or not (when > configuring with --enable-analyze-undefined ALLOW_UNALIGNED is not > defined, otherwise it is for some arches, including x86_64). Looking at = https://github.com/google/oss-fuzz/commit/8747524f04b1b906d4a21a6ade87f780= 3b3f9b8c, I think I turned ALLOW_UNALIGNED off with UBSan there (and tested it in = https://sourceware.org/bugzilla/show_bug.cgi?id=3D28720). Thanks, Evgeny Vereshchagin