From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lf0-x231.google.com ([2a00:1450:4010:c07::231]) by bombadil.infradead.org with esmtps (Exim 4.89 #1 (Red Hat Linux)) id 1eXWYs-0002DV-4E for barebox@lists.infradead.org; Fri, 05 Jan 2018 18:17:48 +0000 Received: by mail-lf0-x231.google.com with SMTP id h5so6019335lfj.2 for ; Fri, 05 Jan 2018 10:17:35 -0800 (PST) Date: Fri, 5 Jan 2018 21:17:30 +0300 From: Peter Mamonov Message-ID: <20180105181730.q65oevjnuixvn5k2@localhost> References: <20171220104814.4snxmloobeywnuwb@localhost.localdomain> <20171221104811.3o2tesuqfr7ej477@localhost.localdomain> <20180105114419.pfb3ouxfogen4y6f@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180105114419.pfb3ouxfogen4y6f@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: command: hashsum: md5sum reports wrong sum for the file named 4k.bin To: Sascha Hauer Cc: barebox@lists.infradead.org On Fri, Jan 05, 2018 at 12:44:19PM +0100, Sascha Hauer wrote: > Hi Peter, > > On Thu, Dec 21, 2017 at 01:48:11PM +0300, Peter Mamonov wrote: > > On Wed, Dec 20, 2017 at 01:48:14PM +0300, Peter Mamonov wrote: > > > Hi, > > > > > > The md5sum command reports wrong sum for a file named 4k.bin and, I guess, for > > > other files named alike. Here are the commands to reproduce the bug: > > > > The problem lays in __do_digest() function: > > - it initializes variables `start` and `size` at commands/digest.c:38 > > - then it calls parse_area_spec(*argv, &start, &size) at commands/digest.c:42 > > - parse_area_spec() returns error as it should, however it changes the value > > of the `start` at lib/misc.c:87. > > - this causes digest algo to skip leading 4k of the data from the file. > > > > I'm not quite sure what is the best solution: > > - prevent parse_area_spec() from setting start if it fails? > > - reinitialize start/size after unsuccessfull call to parse_area_spec()? > > preventing parse_area_spec() from modifying start and size if it fails > seems like a good idea. > > However, this doesn't solve the problem, does it? parse_area_spec() > only fails because the dot in 4k.bin is not valid, but if you name > the file only '4k' then parse_area_spec() won't fail. > The problem is that we cannot know whether '4k' is a file or an area. You are right. However, there is no ambiguity in the "4k.bin" and similar cases, so we can fix at least this obvious problem. Regards, Peter > > Right now I have no good idea how to make the command nonambiguous, > but this will require an incompatible change to the commands arguments. > > Sascha > > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox