Avoid unconditional getrandom syscall creating a WasiCtx
#5244
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This commit updates the default random context inserted into a `WasiCtxt` to be seeded from `thread_rng` rather than the system's entropy. This avoids an unconditional syscall on the creation of all `WasiCtx` structures shouldn't reduce the quality of the random numbers produced.
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pchickey
approved these changes
Nov 10, 2022
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It does reduce quality when forking processes or entire vm's. For cloning vm's acpi allows the virtual machine monitor to tell the vm that a clone has happened, which on linux causes the system csprng to be reseeded. See https://lwn.net/Articles/887207/ |
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Wasmtime hasn't really been written for fork-safety, and otherwise fork-safety seems like it would be part of the |
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This commit updates the default random context inserted into a
WasiCtxtto be seeded fromthread_rngrather than the system's entropy. This avoids an unconditional syscall on the creation of allWasiCtxstructures shouldn't reduce the quality of the random numbers produced.