Support zeroize on wasm targets about crates HOT 8 CLOSED

Using wasm_bindgen you could easily call a js function the problems are:

• dependencies are not supposed to call into js themselves
• you would have to supply the JS side too

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But the pro on wasm is that everything is sandboxed and belongs to the browser, so your memory is protected, but I don't know how the browser clears that memory.

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It looks like bulk memory operations (currently design phase) might be useful for this purpose: https://github.com/WebAssembly/bulk-memory-operations/blob/master/proposals/bulk-memory-operations/Overview.md

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Another approach which might work on stable is to directly emit the WASM necessary to perform a volatile zeroing operation. However, I have never tried that before and wouldn't really know where to start.

Does rust have any way to include things for llvm or assembly?

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so your memory is protected, but I don't know how the browser clears that memory.

My understanding of the WASM memory model in a browser context is it's TypedArray that lives in the DOM, in which case it would be very nice to ensure secrets are cleared, as otherwise they could get potentially exposed unintentionally (ala Cloudbleed / Jetleak).

Does rust have any way to include things for llvm or assembly?

LLVM intrinsics and inline ASM are only available on nightly. But I'm already using volatile_set_memory there.

In an ELF executable, on stable Rust you can include assembly by first creating an object from it, then link that together with Rust code (by e.g. creating a static library and linking with it using FFI + attributes).

I know very little about Rust WASM so I have no idea what the analogous linking operation for that would be.

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Wasm is just like asm there just may be a different Syntax, but I know little about rust and asm so I can't really help there.

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FYI, I think #142 is the path forward here. I'll look into adding a wasm target to CI.

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This was fixed in #142, with CI added in #143

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