chore(bootstrapping-2018): Prepare for depot merge
This commit is contained in:
parent
dfc1ead29d
commit
28200fb059
7 changed files with 0 additions and 0 deletions
142
presentations/bootstrapping-2018/result.pdfpc
Normal file
142
presentations/bootstrapping-2018/result.pdfpc
Normal file
|
@ -0,0 +1,142 @@
|
|||
[file]
|
||||
result
|
||||
[last_saved_slide]
|
||||
10
|
||||
[font_size]
|
||||
20000
|
||||
[notes]
|
||||
### 1
|
||||
- previous discussions of hardware trust (e.g. purism presentation)
|
||||
- people leap to "now I'm on my trusted Debian!"
|
||||
- unless you built it from scratch (spoiler: you haven't) you're *trusting* someone
|
||||
|
||||
Agenda: Implications of trust with focus on bootstrap paths and reproducibility, plus how you can help.### 2
|
||||
self-hosting:
|
||||
- C-family: GCC pre/post 4.7, Clang
|
||||
- Common Lisp: Sunshine land! (with SBCL)
|
||||
- rustc: Bootstrap based on previous versions (C++ transpiler underway!)
|
||||
- many other languages also work this way!
|
||||
|
||||
(Noteable counterexample: Clojure is written in Java!)### 3
|
||||
|
||||
- compilers are just one bit, the various runtimes exist, too!### 4
|
||||
|
||||
Could this be exploited?
|
||||
|
||||
People don't think about where their compiler comes from.
|
||||
|
||||
Even if they do, they may only go so far as to say "I'll just recompile it using <other compiler>".
|
||||
|
||||
Unfortunately, spoiler alert, life isn't that easy in the computer world and yes, exploitation is possible.### 5
|
||||
|
||||
- describe what a quine is
|
||||
- classic Lisp quine
|
||||
- explain demo quine
|
||||
- demo demo quine
|
||||
|
||||
- this is interesting, but not useful - can quines do more than that?### 6
|
||||
|
||||
- quine-relay: "art project" with 128-language circular quine
|
||||
|
||||
- show source of quine-relay
|
||||
|
||||
- (demo quine relay?)
|
||||
|
||||
- side-note: this program is very, very trustworthy!### 7
|
||||
|
||||
Ken Thompson (designer of UNIX and a couple other things!) received Turing award in 1983, and described attack in speech.
|
||||
|
||||
- figure out how to detect self-compilation
|
||||
- make that modification a quine
|
||||
- insert modification into new compiler
|
||||
- add attack code to modification
|
||||
- remove attack from source, distributed binary will still be compromised! it's like evolution :)### 8
|
||||
|
||||
damage potential is basically infinite:
|
||||
|
||||
- classic "login" attack
|
||||
=> also applicable to other credentials
|
||||
|
||||
- attack (weaken) crypto algorithms
|
||||
|
||||
- you can probably think of more!### 10
|
||||
|
||||
idea being: potential vulnerability would have to work across compilers:
|
||||
|
||||
the more compilers we can introduce (e.g. more architectures, different versions, different compilers), the harder it gets for a vulnerability to survive all of those
|
||||
|
||||
The more compilers, the merrier! Lisps are pretty good at this.### 11
|
||||
|
||||
if we get a bit-mismatch after DDC, not all hope is lost: Maybe the thing just isn't reproducible!
|
||||
|
||||
- many reasons for failures
|
||||
- timestamps are a classic! artifacts can be build logs, metadata in ZIP-files or whatever
|
||||
- non-determinism is the devil
|
||||
- sometimes people actively introduce build-randomness (NaCl)### 12
|
||||
|
||||
- Does that binary download on the project's website really match the source?
|
||||
|
||||
- Your Linux packages are signed by someone - cool - but what does that mean?### 13
|
||||
|
||||
Two things should be achieved - gross oversimplification - to get to the ideal "desired state of the union":
|
||||
|
||||
1. full-source bootstrap: without ever introducing any binaries, go from nothing to a full Linux distribution
|
||||
|
||||
2. when packages are distributed, we should be able to know the expected output of a source package beforehand
|
||||
|
||||
=> suddenly binary distributions become a cache! But more on Nix later.### 14
|
||||
|
||||
- Debian project does not seem as concerned with bootstrapping as with reproducibility
|
||||
- Debian mostly bootstraps on new architectures (using cross-compilation and similar techniques, from an existing binary base)
|
||||
- core bootstrap (GCC & friends) is performed with previous Debian version and depending on GCC### 15
|
||||
|
||||
... however! Debian cares about reproducibility.
|
||||
|
||||
- automated testing of reproducibility
|
||||
- information about the status of all packages is made available in repos
|
||||
- Over 90% packages of packages are reproducible!
|
||||
|
||||
< show reproducible builds website >
|
||||
|
||||
Debian is still fundamentally a binary distribution though, but it doesn't have to be that way.### 16
|
||||
|
||||
Nix - a purely functional package manager
|
||||
|
||||
It's not a new project (10+ years), been discussed here before, has multiple components: package manager, language, NixOS.
|
||||
|
||||
Instead of describing *how* to build a thing, Nix describes *what* to build:### 17
|
||||
### 19
|
||||
|
||||
In Nix, it's impossible to say "GCC is the result of applying GCC to the GCC source", because that happens to be infinite recursion.
|
||||
|
||||
Bootstrapping in Nix works by introducing a binary pinned by its full-hash, which was built on some previous Nix version.
|
||||
|
||||
Unfortunately also just a magic binary blob ... ### 20
|
||||
|
||||
NixOS is not actively porting all of Debian's reproducibility patches, but builds are fully repeatable:
|
||||
|
||||
- introducing a malicious compiler would produce a different input hash -> different package
|
||||
|
||||
Future slide: hope is not lost! Things are underway.### 21
|
||||
|
||||
- bootstrappable.org (demo?) is an umbrella page for several projects working on bootstrappability
|
||||
|
||||
- stage0 is an important piece: manually, small, auditable Hex programs to get to a Hex macro expander
|
||||
|
||||
- end goal is a full-source bootrap, but pieces are missing### 22
|
||||
|
||||
MES is out of the GuixSD circles (explain Guix, GNU Hurd joke)
|
||||
|
||||
- idea being that once you have a Lisp, you have all of computing (as Alan Key said)
|
||||
|
||||
- includes MesCC in Scheme -> can *almost* make a working tinyCC -> can *almost* make a working gcc 4.7
|
||||
|
||||
- minimal Scheme interpreter, currently built in C to get the higher-level stuff to work, goal is rewrite in hex
|
||||
- bootstrapping Guix is the end goal### 23
|
||||
|
||||
- userspace in Darwin has a Nix project
|
||||
- unsure about other BSDs, but if anyone knows - input welcome!
|
||||
- F-Droid has reproducible Android packages, but that's also userspace only
|
||||
- All other mobile platforms are a lost cause
|
||||
|
||||
Generally, all closed-source software is impossible to trust.
|
Loading…
Add table
Add a link
Reference in a new issue