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Bootstrapping from Hex to Bison to GCC

by z29LiTp5qUC30n on 5/3/21, 9:25 AM with 19 comments

• by markjenkinswpg on 5/3/21, 11:03 PM

  Nice work Fossy and co.

  I believe this is this is the dependency chain your live-bootstrap works through: https://github.com/oriansj/talk-notes/raw/master/live-bootst...

• by userbinator on 5/4/21, 12:01 AM

  See also Bellard's TCCBOOT, which is based on the far simpler TCC instead of GCC: https://bellard.org/tcc/tccboot.html

• by XorNot on 5/4/21, 12:29 AM

  This is cool as heck. Outside of architectural attacks, this seems like a practical response to Reflections on Trusting Trust (http://users.ece.cmu.edu/~ganger/712.fall02/papers/p761-thom...).

  While we can definitely discuss whether it's practical for anyone to actually audit all that source code (no it is not), proving a 356 bytes codestream isn't malicious seems like a good foundation to argue about.

• by siraben on 5/4/21, 12:48 AM

  See also blynn-compiler[0], made by the same contributors, that bootstrap a Haskell compiler from C (which in term is bootstrapped from hex).

  [0] https://github.com/oriansj/blynn-compiler

• by Aissen on 5/4/21, 7:47 AM

  See this doc for how the full process works: https://github.com/fosslinux/live-bootstrap/blob/master/part...

  In particular, this the very first step: https://github.com/oriansj/stage0-posix/blob/master/x86/hex0... (or its hand-edited binary version ?)

  Edit: this how it's "assembled":

      sed 's/[;#].*$//g' $input_file | xxd -r -p > $output_file
  

  See: https://github.com/oriansj/bootstrap-seeds/blob/master/READM...

• by fjfaase on 5/4/21, 9:19 AM

  I wonder if Brainfuck could be used for https://github.com/oriansj/stage0-posix ? It would not surprise me if there is no other language for which there are so many interpreters written in so many different programming languages. It is even possible to write a Brainfuck interpreter in Brainfuck, which can be verified. And there is also a Brainfuck interpreter written in x86-64: https://github.com/316k/brainfuck-x86-64 . It is a little larger than hex0_x86.hex0 , but not too much to make it hard to verify.

• by choeger on 5/4/21, 6:27 AM

  So, how about the kernel, eh? ;)