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> Can somebody let me know why one cannot just take the assembly version of an existing compiler and carefully review its code to be happy with it and then buil

• selfhoster11 5y ago
  It's worth noting that the above comment, while it might sound paranoid to some, is IMO entirely justified. I'm 50/50 on whether someone at some point hasn't executed a successful Trusting Trust attack (see Ken Thompson). With modern machines that have megabytes of binary blobs, different co-processors that have access to the RAM while they can't be reprogrammed to be on the user's side, and techniques that can actually tell when sensitive operations are happening, such attacks are becoming more feasible.
  • pabs3 5y ago
    There definitely have been compromised build toolchains before: https://en.wikipedia.org/wiki/XcodeGhost https://en.wikipedia.org/wiki/XcodeGhost
    • selfhoster11 5y ago
      Thank you, I wasn't familiar with this case.
    • tremon 5y ago
      That's only half of the trusting trust-attack though; the other half is being able to make the compiler compromise propagate itself, i.e. not just inserting any backdoor in compiled code, but inserting itself in any compiler built using the compromised tool.
      • selfhoster11 5y ago
        Mobile and Electron apps often weight hundreds of megs. That's enough data to hide an entire classic-style OS in the spaces between the data. While I don't know whether someone did insert such a recursive compiler, they certainly can do it unobtrusively enough that it doesn't raise any suspicion.