Date: Mon, 16 Feb 2015 22:31:32 -0600 From: Sean DuBois <sean@siobud.com> To: Greg 'groggy' Lehey <grog@FreeBSD.org> Cc: freebsd-chat@freebsd.org, "Jason C. Wells" <jasoncwells@fastmail.com> Subject: Re: Analyze and Edit a Binary File Message-ID: <20150217043132.GA91832@3006.local> In-Reply-To: <20150217040026.GA91708@eureka.lemis.com> References: <1424140628.3400388.228383569.629B0401@webmail.messagingengine.com> <20150217040026.GA91708@eureka.lemis.com>
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Oh also another idea. Try saving the same file in multiple versions of the program, and then diffing them. Another good trick would be to use LD_PRELOAD, and throw some debugging in places like strcmp etc.. And in the same vein as LD_PRELOAD try using strace I imagine Catia has all symbols stripped, so it will be sort of hard to analyze/debug. BUT you might get lucky, so worth checking :) On Tue, Feb 17, 2015 at 03:00:26PM +1100, Greg 'groggy' Lehey wrote: > On Monday, 16 February 2015 at 18:37:08 -0800, Jason C. Wells wrote: > > > > I use some engineering software called Catia. The files produced by > > Catia encode a software version number. If the version number is > > greater than the version of the installed software, Catia refuses to > > open the file. This is annoying in the extreme. Especially if you want > > to share files in the spirit of open source. If the files that I create > > are newer than the Catia version of my audience, then my audience can't > > use my files. > > > > My question to my more knowledgeable computer geek friends: How do I > > analyze and edit an arbitrary binary file? > > Those are two different questions, of course. You know the version > number; if it's relatively complicated (2.2.7.1, for example), it may > be stored as character text. In that case, there will be relatively > few false positives if you search for the text. If it's simple (2, > for example), you'd need to run the software in a debugger and find > where it does the comparison. That's much more difficult. > > As for editing: Emacs, of course :-) > > Seriously, it does work. I've used it on occasion, and at least one > package I've seen asks you to edit binary files with Emacs as part of > the build process. Just make very sure not to change the length of > the file. > > Greg > -- > Sent from my desktop computer. > Finger grog@FreeBSD.org for PGP public key. > See complete headers for address and phone numbers. > This message is digitally signed. If your Microsoft MUA reports > problems, please read http://tinyurl.com/broken-mua
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