Lambda the Ultimate

Here is a very interesting article addressing a well known compiler problem.

Date: Mon, 12 Dec 2005 17:03:54 -0500
From: David A. Wheeler 
To: bugtraq@securityfocus.com
Subject: Countering Trusting Trust through Diverse Double-Compiling

Everyone here should be familiar with Ken Thompson's famous
"Reflections on Trusting Trust." If not, see:
 http://www.acm.org/classics/sep95/
The "trusting trust" attack subverts the compiler binary;
if attacker succeeds, you're doomed. Well, til now.

I've written a paper on an approach to counter this attack. See:
 "Countering Trusting Trust through Diverse Double-Compiling"
 http://www.acsa-admin.org/2005/abstracts/47.html

Here's the abstract:
"An Air Force evaluation of Multics, and Ken Thompson's famous Turing award
lecture "Reflections on Trusting Trust," showed that compilers can be subverted
to insert malicious Trojan horses into critical software, including themselves.
If this attack goes undetected, even complete analysis of a system's source code
will not find the malicious code that is running, and methods for detecting this
particular attack are not widely known. This paper describes a practical
technique, termed diverse double-compiling (DDC),
that detects this attack and some unintended compiler defects as well.
Simply recompile the purported source code twice: once with a second (trusted)
compiler, and again using the result of the first compilation.
If the result is bit-for-bit identical with the untrusted
binary, then the source code accurately represents the binary.
This technique has been mentioned informally, but its issues and
ramifications have not been identified or discussed in a
peer-reviewed work, nor has a public demonstration been made.
This paper describes the technique, justifies it, describes how
to overcome practical challenges, and demonstrates it."

I think you'll find this interesting.

--- David A. Wheeler

I'm looking for references to virtual machine implementations and dynamic languages.

I seem to recall something recently about what the Java VM lacks wrt dynamic languages and what other implementations (Parrot?) do that enable dynamic languages.

What would a Universal VM look like? Is such a thing possible?

I'm not googling the right keywords, I'm not finding what I'm looking for.

I was dusting off my old copy of "The AWK Programming Language" by Aho, Weinberger and Kernighan (IMHO, one of the best programming books ever written) and decided to see what was being done with AWK these days.

A very interesting networking extension has been added to gawk called Gawkinet. What is particularly interesting is how they managed to add networking capabilities to the language by introducing one new operator "|&" and treating network addresses like files. Leading to examples like:

     
BEGIN {
       "/inet/tcp/0/localhost/daytime" |& getline
       print $0
       close("/inet/tcp/0/localhost/daytime")
     }

Interesting...