141 lines
3.3 KiB
TeX
141 lines
3.3 KiB
TeX
\documentclass[12pt]{beamer}
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\usetheme{metropolis}
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\newenvironment{code}{\ttfamily}{\par}
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\title{Where does \textit{your} compiler come from?}
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\date{2018-03-13}
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\author{Vincent Ambo}
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\institute{Norwegian Unix User Group}
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\begin{document}
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\maketitle
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%% Slide 1:
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\section{Introduction}
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%% Slide 2:
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\begin{frame}{Chicken and egg}
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Self-hosted compilers are often built using themselves, for example:
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\begin{itemize}
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\item C-family compilers bootstrap themselves \& each other
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\item (Some!) Common Lisp compilers can bootstrap each other
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\item \texttt{rustc} bootstraps itself with a previous version
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\item ... same for many other languages!
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\end{itemize}
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\end{frame}
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%% Slide 3:
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\begin{frame}{Trusting Trust}
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\begin{center}
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Could this be exploited?
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\end{center}
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\end{frame}
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%% Slide 4:
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\begin{frame}{Short interlude: A quine}
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\begin{center}
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\begin{code}
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((lambda (x) (list x (list 'quote x)))
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\newline\vspace*{6mm} '(lambda (x) (list x (list 'quote x))))
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\end{code}
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\end{center}
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\end{frame}
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%% Slide 5:
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\begin{frame}{Short interlude: Quine Relay}
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\begin{center}
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\includegraphics[
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keepaspectratio=true,
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height=\textheight
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]{quine-relay.png}
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\end{center}
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\end{frame}
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%% Slide 6:
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\begin{frame}{Trusting Trust}
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An attack described by Ken Thompson in 1984:
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\begin{enumerate}
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\item Modify a compiler to detect when it's compiling itself.
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\item Let the modification insert \textit{itself} into the new compiler.
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\item Add arbitrary attack code to the modification.
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\end{enumerate}
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\end{frame}
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%% Slide 7:
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\begin{frame}{Damage potential?}
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\begin{center}
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Let your imagination run wild!
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\end{center}
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\end{frame}
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%% Slide 8:
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\section{Countermeasures}
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%% Slide 9:
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\begin{frame}{Diverse Double-Compiling}
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Assume we have:
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\begin{itemize}
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\item Target language compilers $A$ and $T$
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\item The source code of $A$: $ S_{A} $
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\end{itemize}
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\end{frame}
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%% Slide 10:
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\begin{frame}{Diverse Double-Compiling}
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Apply the first stage (functional equivalence):
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\begin{itemize}
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\item $ X = A(S_{A})$
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\item $ Y = T(S_{A})$
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\end{itemize}
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Apply the second stage (bit-for-bit equivalence):
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\begin{itemize}
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\item $ V = X(S_{A})$
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\item $ W = Y(S_{A})$
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\end{itemize}
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Now we have a new problem: Reproducibility!
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\end{frame}
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%% Slide 11:
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\begin{frame}{Reproducibility}
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Bit-for-bit equivalent output is hard, for example:
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\begin{itemize}
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\item Timestamps in output artifacts
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\item Non-deterministic linking order in concurrent builds
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\item Non-deterministic VM \& memory states in outputs
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\item Randomness in builds (sic!)
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\end{itemize}
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\end{frame}
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%% Slide 12:
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\section{(Partial) State of the Union}
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\begin{frame}{Bootstrapping Debian}
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\end{frame}
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\begin{frame}{Bootstrapping NixOS}
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\end{frame}
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\section{The future of bootstrapping}
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\begin{frame}{MES}
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\end{frame}
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\begin{frame}{The Nix project(s)}
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\end{frame}
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\begin{frame}{Other platforms}
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\end{frame}
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%% Next up: Debian, Fedora, NixOS
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%% Next up: Relevant projects: Nix, MES
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%% Next up: There's hope, but don't even think about phones ...
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\end{document}
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