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diff --git a/presentations/bootstrapping-2018/presentation.tex b/presentations/bootstrapping-2018/presentation.tex new file mode 100644 index 0000000000..d3aa613375 --- /dev/null +++ b/presentations/bootstrapping-2018/presentation.tex @@ -0,0 +1,251 @@ +\documentclass[12pt]{beamer} +\usetheme{metropolis} +\newenvironment{code}{\ttfamily}{\par} +\title{Where does \textit{your} compiler come from?} +\date{2018-03-13} +\author{Vincent Ambo} +\institute{Norwegian Unix User Group} +\begin{document} + \maketitle + + %% Slide 1: + \section{Introduction} + + %% Slide 2: + \begin{frame}{Chicken and egg} + Self-hosted compilers are often built using themselves, for example: + + \begin{itemize} + \item C-family compilers bootstrap themselves \& each other + \item (Some!) Common Lisp compilers can bootstrap each other + \item \texttt{rustc} bootstraps itself with a previous version + \item ... same for many other languages! + \end{itemize} + \end{frame} + + \begin{frame}{Chicken, egg and ... lizard?} + It's not just compilers: Languages have runtimes, too. + + \begin{itemize} + \item JVM is implemented in C++ + \item Erlang-VM is C + \item Haskell runtime is C + \end{itemize} + + ... we can't ever get away from C, can we? + \end{frame} + + %% Slide 3: + \begin{frame}{Trusting Trust} + \begin{center} + \huge{Could this be exploited?} + \end{center} + \end{frame} + + %% Slide 4: + \begin{frame}{Short interlude: A quine} + \begin{center} + \begin{code} + ((lambda (x) (list x (list 'quote x))) + \newline\vspace*{6mm} '(lambda (x) (list x (list 'quote x)))) + \end{code} + \end{center} + \end{frame} + + %% Slide 5: + \begin{frame}{Short interlude: Quine Relay} + \begin{center} + \includegraphics[ + keepaspectratio=true, + height=\textheight + ]{quine-relay.png} + \end{center} + \end{frame} + + %% Slide 6: + \begin{frame}{Trusting Trust} + An attack described by Ken Thompson in 1983: + + \begin{enumerate} + \item Modify a compiler to detect when it's compiling itself. + \item Let the modification insert \textit{itself} into the new compiler. + \item Add arbitrary attack code to the modification. + \item \textit{Optional!} Remove the attack from the source after compilation. + \end{enumerate} + \end{frame} + + %% Slide 7: + \begin{frame}{Damage potential?} + \begin{center} + \large{Let your imagination run wild!} + \end{center} + \end{frame} + + %% Slide 8: + \section{Countermeasures} + + %% Slide 9: + \begin{frame}{Diverse Double-Compiling} + Assume we have: + + \begin{itemize} + \item Target language compilers $A$ and $T$ + \item The source code of $A$: $ S_{A} $ + \end{itemize} + \end{frame} + + %% Slide 10: + \begin{frame}{Diverse Double-Compiling} + Apply the first stage (functional equivalence): + + \begin{itemize} + \item $ X = A(S_{A})$ + \item $ Y = T(S_{A})$ + \end{itemize} + + Apply the second stage (bit-for-bit equivalence): + + \begin{itemize} + \item $ V = X(S_{A})$ + \item $ W = Y(S_{A})$ + \end{itemize} + + Now we have a new problem: Reproducibility! + \end{frame} + + %% Slide 11: + \begin{frame}{Reproducibility} + Bit-for-bit equivalent output is hard, for example: + + \begin{itemize} + \item Timestamps in output artifacts + \item Non-deterministic linking order in concurrent builds + \item Non-deterministic VM \& memory states in outputs + \item Randomness in builds (sic!) + \end{itemize} + \end{frame} + + \begin{frame}{Reproducibility} + \begin{center} + Without reproducibility, we can never trust that any shipped + binary matches the source code! + \end{center} + \end{frame} + + %% Slide 12: + \section{(Partial) State of the Union} + + \begin{frame}{The Desired State} + \begin{center} + \begin{enumerate} + \item Full-source bootstrap! + \item All packages reproducible! + \end{enumerate} + \end{center} + \end{frame} + + %% Slide 13: + \begin{frame}{Bootstrapping Debian} + \begin{itemize} + \item Sparse information on the Debian-wiki + \item Bootstrapping discussions mostly resolve around new architectures + \item GCC is compiled by depending on previous versions of GCC + \end{itemize} + \end{frame} + + \begin{frame}{Reproducing Debian} + Debian has a very active effort for reproducible builds: + + \begin{itemize} + \item Organised information about reproducibility status + \item Over 90\% reproducibility in Debian package base! + \end{itemize} + \end{frame} + + \begin{frame}{Short interlude: Nix} + \begin{center} + \includegraphics[ + keepaspectratio=true, + height=0.7\textheight + ]{nixos-logo.png} + \end{center} + \end{frame} + + \begin{frame}{Short interlude: Nix} + \begin{center} + \includegraphics[ + keepaspectratio=true, + height=0.90\textheight + ]{drake-meme.png} + \end{center} + \end{frame} + + \begin{frame}{Short interlude: Nix} + \begin{center} + \includegraphics[ + keepaspectratio=true, + height=0.7\textheight + ]{nixos-logo.png} + \end{center} + \end{frame} + + \begin{frame}{Bootstrapping NixOS} + Nix evaluation can not recurse forever: The bootstrap can not + simply depend on a previous GCC. + + Workaround: \texttt{bootstrap-tools} tarball from a previous + binary cache is fetched and used. + + An unfortunate magic binary blob ... + \end{frame} + + \begin{frame}{Reproducing NixOS} + Not all reproducibility patches have been ported from Debian. + + However: Builds are fully repeatable via the Nix fundamentals! + \end{frame} + + \section{Future Developments} + + \begin{frame}{Bootstrappable: stage0} + Hand-rolled ``Cthulhu's Path to Madness'' hex-programs: + + \begin{itemize} + \item No non-auditable binary blobs + \item Aims for understandability by 70\% of programmers + \item End goal is a full-source bootstrap of GCC + \end{itemize} + \end{frame} + + + \begin{frame}{Bootstrappable: MES} + Bootstrapping the ``Maxwell Equations of Software'': + + \begin{itemize} + \item Minimal C-compiler written in Scheme + \item Minimal Scheme-interpreter (currently in C, but intended to + be rewritten in stage0 macros) + \item End goal is full-source bootstrap of the entire GuixSD + \end{itemize} + \end{frame} + + \begin{frame}{Other platforms} + \begin{itemize} + \item Nix for Darwin is actively maintained + \item F-Droid Android repository works towards fully reproducible + builds of (open) Android software + \item Mobile devices (phones, tablets, etc.) are a lost cause at + the moment + \end{itemize} + \end{frame} + + \begin{frame}{Thanks!} + Resources: + \begin{itemize} + \item bootstrappable.org + \item reproducible-builds.org + \end{itemize} + + @tazjin | mail@tazj.in + \end{frame} +\end{document} |