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Comment by saagarjha | Hacker News Reader

> The reality is which almost everyone can see is that memory safe languages are pretty much always what you want to be using for new code.

Nitpick, this is not quite true. Memory safe languages are what you should be using in contexts where security and reliability are critical. This is generally the case but there are some contexts where other concerns are genuinely more important. Of course when this is necessary is often misrepresented but these cases do exist.

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writing exploits, for example, is an utter pain in today's safe languages :) C is unmatched in the sheer ease of manipulating raw bytes with some light structuring on top for convenience. I've tried writing exploits in Swift a handful of times but I always gave up after I found myself buried under a pile of UnsafeMutableRawBufferPointers.

You mean, manipulating strings of bytes? Bytes don't have to be memory, you can just use bytestrings in Python or whatever.

Raw memory access is something you normally need to create vulnerabilities, not to exploit them :)

har har :)

It's an ergonomics thing, not a "can't" issue. There is a reason I called out Swift in particular—their "unsafe" APIs are so horrid to use that they make you regret doing unsafe things in the first place. Plus, throw in FFI and now you've got an even worse problem because not only are you forced to use the unsafe types, but often a lot of the critical APIs you need to interface with (in *OS exploitation, mach is the worst offender) have such funky types due to their generic nature that you have to go through half a dozen different conversions to get access to the underlying data.

I still don't understand why would you prefer raw memory manipulation to bytestring manipulation. If you want, just make a Swift library that will implement the memory like you want but without unsafe raw access (but just a few methods over a byte array). Back in the days when I did CTFs, I used Python for writing binary exploits, never C.

https://github.com/hellman/libformatstr

You can do something like this, no need to work with raw memory.

Swift has the advantage that it can directly “speak” C, without any indirection needed. (C can already do this of course.) In particular operations like scanning an address space for things, easily expressing the layout of something, and so on are much easier to do in these languages. In theory you could do the same in Python but it’s often not worth the effort.

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