From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from resqmta-a1p-077437.sys.comcast.net (resqmta-a1p-077437.sys.comcast.net [IPv6:2001:558:fd01:2bb4::8]) by sourceware.org (Postfix) with ESMTPS id D9064385840D for ; Wed, 15 Feb 2023 21:29:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D9064385840D Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=comcast.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=comcast.net Received: from resomta-a1p-076781.sys.comcast.net ([96.103.145.226]) by resqmta-a1p-077437.sys.comcast.net with ESMTP id SIiIpZlLEKJmTSPKvpk5sN; Wed, 15 Feb 2023 21:29:09 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1676496549; bh=WwMFwXRgkUjITcjCqNrfjK0YMxd8cfyPjN5vrYSeYjE=; h=Received:Received:Content-Type:Mime-Version:Subject:From:Date: Message-Id:To:Xfinity-Spam-Result; b=b+XXjHt4lmTY/a/3KlDt/wBaTLB7aLhxati+OK/4zle5J5aI1XH7Fshc6MzsawdiP WccGPUGmgNWMrco06BRUaLuhXOOgM1dNqng+klQntOU4XuhXS0bPTlD5M2Z9jxTTjL TkXgPaJmS1/s2QSdcwuyie70dtB6GRtwcLmFSmIM+wdhq9TchVVlDOrrdGVJeITU9m 4H3jmjyYi3kV9ZLKZ2zDlMRkZaWAIDwtVET3IugMdG/PUNO7rHesOKOOyXGUtnnKax 8fV5KLxiK2aikWxuIXGeDp9m47x1Zg1azKhva06+f9TAEkystENsw0AmWv5VKqWQuE +IxPRA24UJRIw== Received: from smtpclient.apple ([73.60.223.101]) by resomta-a1p-076781.sys.comcast.net with ESMTPSA id SPKspX5GSH2imSPKtpovgp; Wed, 15 Feb 2023 21:29:08 +0000 X-Xfinity-VAAS: gggruggvucftvghtrhhoucdtuddrgedvhedrudeihedgudegvdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucevohhmtggrshhtqdftvghsihdpqfgfvfdppffquffrtefokffrnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpegtggfuhfgjffevgffkfhfvofesthhqmhdthhdtvdenucfhrhhomheprfgruhhlucfmohhnihhnghcuoehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvtheqnecuggftrfgrthhtvghrnhepveekveelffeliefgiedufeehgeejtdfhgedujeehueekiedtgfetffevgffggfdvnecukfhppeejfedriedtrddvvdefrddutddunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehhvghlohepshhmthhptghlihgvnhhtrdgrphhplhgvpdhinhgvthepjeefrdeitddrvddvfedruddtuddpmhgrihhlfhhrohhmpehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvthdpnhgspghrtghpthhtohepfedprhgtphhtthhopegsihhnuhhtihhlshesvghmrghgihhirdgtohhmpdhrtghpthhtohepnhhitghktgesrhgvughhrghtrdgtohhmpdhrtghpthhtohepsghinhhuthhilhhssehsohhurhgtvgifrghrvgdrohhrgh X-Xfinity-VMeta: sc=-100.00;st=legit Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.2\)) Subject: Re: RFC: generating a header using the linker (CRC calculation) From: Paul Koning In-Reply-To: Date: Wed, 15 Feb 2023 16:29:06 -0500 Cc: Nick Clifton , binutils@sourceware.org Content-Transfer-Encoding: quoted-printable Message-Id: <8511B960-E529-47FB-9B17-55F666B58EE7@comcast.net> References: <5aa83cea-b8ad-5b36-12ec-6857a5c5541a@redhat.com> <73f54df1-c236-4c4a-c161-85ebe6d6f7b7@emagii.com> <7216fa28-4769-5bd2-a508-bf71184727fd@redhat.com> <4e60f02f-322e-f268-cb31-a4e52a419fc6@emagii.com> To: Ulf Samuelsson X-Mailer: Apple Mail (2.3696.120.41.1.2) X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > On Feb 15, 2023, at 4:01 PM, Ulf Samuelsson via Binutils = wrote: >=20 > Some argument for including CRC support in the linker. >=20 > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >=20 > The AUTOSAR organisation publishes requirement for developing code for = the Automotive industry. >=20 > Protecting your code with a CRC is mandatory, and the chosen algorithm = is CRC64 ECMA. > ... > You cannot get a Functional Safety device qualified, if the firmware = is not protected by a CRC. > ... > So there is a significant part of the embedded industry that relies on = CRC calculations for ensuring that their systems are not broken. >=20 > What is important here is the "Hamming distance" which measures the = quality of detection. >=20 > The width of the CRC needs to grow as the program size grows. Indeed; CRC32 is not suitable for that reason. But what about other options? CRC64 is certainly one reasonable = integrity check (if the assumption is that errors are unintentional as = opposed to the result of active attack). But SHA-1, SHA-2, or even MD-5 = are at least as good. Digital signatures provide protection against = intentional modification. Does the standard recognize that those other = options are also suitable? paul