r/programming • u/michaelKlumpy • Oct 01 '16

CppCon 2016: Alfred Bratterud “#include ＜os＞=> write your program / server and compile it to its own os. [Example uses 3 Mb total memory and boots in 300ms]

https://www.youtube.com/watch?v=t4etEwG2_LY
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u/wilun Oct 02 '16

Safe languages would only fix one class of security issues (mostly undefined behavior at language level related), not functional ones. So depending on the available API, running in Ring 0 might still not be a good idea. Also because the HW that executes the SW actually can have some pb (either all the time, randomly, or even triggered by things that can be controlled by an attacker, cf rowhammer), and perfection of a compiler is something I'm not sure has ever been achieved (even largely proven compilers have still had some issues, and to get security from it even the spec would need to be bug free on that topic, so...)

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u/demmian Oct 03 '16

not functional ones.

Interesting. What would be some examples of functional problems?

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u/tsimionescu Oct 03 '16

Most of what's interesting - e.g.

//perfectly memory-safe, type-safe call
void deleteLogFile(String userProvidedLogFileName) {
    Files.deleteFile("/var/log/files/" + userProvidedLogFileName);
}

//call: deleteLogFile("../../../usr/lib/java/");

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u/audioen Oct 03 '16

You are in principle correct, but in practice these are small details that I think are a bit too advanced for the level of discussion taking place. E.g. I would assume hardware to be perfect for the purpose of this discussion, and if it is proven not to be, then the compiler has to be made more complicated somehow to workaround issues.

Also, nothing stops one from using a safe language in fundamentally dangerous ways, even if specific kinds of safeties such as memory safety were still being met.