And while WASM trumps the security trumpet, without actually supporting proper bounds checking, the CLR will taint C++ pointer arithmetic as unsafe, thus making the whole module unsafe.
So I as consumer can decide if I am willing to trust an unsafe module or not.
The CLR doesn’t guarantee control flow integrity (modulo type confusion) or any form of isolation when linear memory accesses are used. So here WASM offers another option in the middle between trust and don’t trust: “trust unsafe module only to not compromise its own functionality; no attacking the rest of the process or kernel” (modulo runtime bugs).
Note for C++ on the CLR that you can use /clr:safe as an MSVC compilation argument. This errors out when trying to access to random pointers at compile time.
/clr:pure uses unsafe and supports those cases though.
And yeah, WebAssembly only doing bounds checking within a single memory block and not actually offering true bounds checking is a big downgrade, and a pretty much unjustified one (+ it's rare among JITted languages...).
If you care about "true" bounds checking, just compile to Wasm from a safe source language. Besides, Wasm does support multiple memory blocks so a potentially-unsafe module need not "taint" anything else.
Memory blocks have a page granularity, which makes them useless for pervasive checking. (+ you can do the same thing to a reasonable extent with C even, with guard pages.)
And while WASM trumps the security trumpet, without actually supporting proper bounds checking, the CLR will taint C++ pointer arithmetic as unsafe, thus making the whole module unsafe.
So I as consumer can decide if I am willing to trust an unsafe module or not.