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I'm curious, is this anything like the Address Space Randomization that's new to Vista, only for regular applications as well as system files?

Or do I have this all wrong?

I do see some mentions of extra features like protecting against dangling pointers and uninitialized reads, but short of DieHard knowing where the pointers are supposed to point and what the reads are supposed to read... well, I guess I'm not really qualified to understand how all this works.

Anyway, it doesn't look like it will protect against all bugs, but it still sounds rather useful. I do wonder whether the performance hit from running multiple versions of the program (in 'replicated' mode) would really make it worthwhile. Maybe for a few important and buggy applications... I see it works on Linux; I might have to try it sometime

It says they eliminate double free's and invalid free's. This makes me suspicious that they've just attached garbage collection with random allocation addresses.

It also says they're running multiple concurrent copies of the process (interesting, if not totally ridiculous) so that when one crashes they can just throw another one up (not sure how they're making sure the second one doesn't crash in the same way...).

Edit:
Nevermind, there powerpoint shows they're not doing this. They're just marking each allocation and then checking on a free if the allocation is valid and if it's really still allocated.

Edited 2007-01-03 18:41

Apparently it increases Firefox's memory consumption by 50-75% (according to the website).

With Firefox already eating gobs of memory (hell, it's why I switched away from it), that's just ridiculous.

Well maybe making the web page compliant for a start will avoid it crashing ? W3C html validator finds 10 errors on the page and particularly the "This page is not Valid (no Doctype found)!".

Next we will have an app that avoids 'DieHard' to die ?

I downloaded and installed Die Hard for Firefox. I then ran Firefox. It immediately crashed, twice in a row. Then it ran for a bit, with Die Hard active (I could tell because Die Hard inserted "[Die Hard]" into the title bar), until I tried to load osnews.com, and it crashed again. Currently Firefox crashes immediately on launching.

This is with Firefox 2.0.0.1 - now, granted I've not found this version to be particularly stable on my machine, but it was running fine until I launched Die Hard. There doesn't appear to be any exe I can kill to remove Die Hard, so it appears I will have to reboot to fix it.

Is it just me or does this look like a fresh implementation of technologies that OpenBSD has had for quite a while?

It sounds a good piece of development but not perhaps totally novel research.

Also appears to back up the notion that reliability and security are a function of engineered quality rather than how long your track record is at CERT.

The canard that (say) OpenBSD only appears secure because fewer people use it and therefore it gets attacked less is part of nonsensical viewpoint that still believes in security by obscurity.

This is an end-of-the-pipe solution: instead of ensuring that software is written according to a high enough standard, DieHard increases the chance that buggy software works. Why doesn't it surprise me that this kind of research was sponsored by Microsoft ?

The basic premise is wrong: "programmers are still writing code as if memory is in short supply"

If you use less memory to store your data, more data fits in the cache. So for performance's sake, it's always a good idea not to waste space.
Anyway, you still want to save memory so that memory consumption scale reasonably when your application handle a lot of data.

And then, randomizing addresses... It sounds horrible when it comes to heap fragmentation, plus if a lot of small objects are allocated, it will waste a lot of physical memory because each allocated block will get its own 4kb memory page.

Edited 2007-01-03 19:26

This appears to be addressed in the FAQ on the DieHard site:

"How does DieHard differ from Vista's, OpenBSD's, and Linux's "address space randomization"?

http://prisms.cs.umass.edu/emery/index.php?page=frequently-asked-qu...

I thought the name Emery berger rung a bell. of course! I remember...the same guy who made Hoard. http://www.hoard.org/

It still remains to be seen how useful it is (since the memory tradeoff is pretty steep), but kudos to Microsoft, Intel, and the US National Science Foundation for making the work available.

Ok, the article says this:

The problems Berger wanted to address were caused by the fact that despite the huge amount of memory installed in today's PCs, "programmers are still writing code as if memory is in short supply".

No, the problem is that "researchers" like THIS enable bad developers to continue writing bad software:

DieHard also secretly launches multiple copies of some applications, so that when one application is about to crash it can be shut down, while the others continue to run.

So, HIDE the problem from the user - nice... the user will continue using "bad" software and developers will continue being lazy.

and

One caveat is that DieHard noticeably increases memory usage - a rise of 50 to 75 percent, according to Berger. Application performance shouldn't be noticeably altered, though, as long as the system has sufficient memory.

It appears the reason this works is because it basically DOESN'T free the memory, even when the developer asks for it. This is a great way to take the power of C/C++ to write tight, memory-efficient, fast code and flush it down the drain.

What a crock of shit. I use Firefox, and certainly don't need this crap to use it. Afterall, Firefox is just an app, it's not my whole OS.

...that OSS/Linux projects has lame and "unprofessional" names...

Edited 2007-01-04 01:06

When i read this i immitiatly thoughed of whenthrust:

http://www.wehnus.com/index.pl

ill believe i see it, and test test test it

omg windoze fans are braindead


notice how i didnt say windoze users- that would be hypocrisy- i am a windows user (i have to be at work- thanks to a braindead stupid IT admin) but i prefer Linux specifically debian (for its stability)


my favourite icebreaker to girls- computers are like airconditioners- they're useless when you open windows

Yippie kay yay!

One caveat is that DieHard noticeably increases memory usage - a rise of 50 to 75 percent

Microsoft's standard operating procedure (SOP) for years has been to release software that uses more hardware resources than previous versions. This is hugely advantageous for them because of the following scenario.

You buy an upgrade to your Microsoft software and install it on your existing hardware. Then you notice your computer seems slow, so you conclude that you need a new computer and you buy one. But you just bought a new copy of the software, so you don't need to buy yet another one with the new computer, right? Too bad! Microsoft demands that you buy another copy.

By forcing a hardware upgrade, they caused you to buy TWO copies of their new version instead of only the one that you needed.

Seems like plenty of folks seem to think you shouldn't allocate more memory than needed.

I am personally tired of seeing code like:
char name[7];
strcpy(name, "bob rob");

Especially if its on the stack. Why would you ever allocate exactly 7 chars? Is this case, its a bug. But even if it weren't, why not just allocate a reasonable large buffer. char name[64] or even 128.

Programmers micromanaging memory is a huge problem. Yes, for large arrays/collections of data, you should optimize it, but in general...allocate more. For arrays, allocate 1 or 2 more than your predetermined size.

I'd be nervous using a bridge that would only hold exactly my weight. People using arrayd should feel the same way