Stream: git-wasmtime

Topic: wasmtime / PR #14397 wasi: don't panic on out-of-range da...

Wasmtime GitHub notifications bot (Sep 24 2026 at 14:16):

xia-chao opened PR #14397 from xia-chao:fix-wasi-datetime-overflow to bytecodealliance:main:

Fixes a guest-triggerable panic in the preview 2 filesystem host functions.

wall_clock.datetime comes straight from the guest, and systemtime_from hands it to Duration::new. That constructor carries nanoseconds of 1e9 or more into the seconds field and panics when the addition overflows, so a guest passing seconds u64::MAX with nanoseconds 1000000000 takes down the whole host process (exit status 101) instead of getting overflow back. One nanosecond less, 999999999, returns overflow correctly, because it is the carry that pushes the value over.

The checked_add(...).ok_or(ErrorCode::Overflow) right below was meant to catch this, but Duration::new is evaluated first, so that line never runs.

I applied the carry before building the Duration, which sends every out-of-range datetime down the existing error path. Times that already worked, including the in-range carry, behave the same as before.

Reproduced with a small wasm32-wasip2 component that calls set_times_at.

Wasmtime GitHub notifications bot (Sep 24 2026 at 14:17):

xia-chao requested rvolosatovs for a review on PR #14397.

Wasmtime GitHub notifications bot (Sep 24 2026 at 14:17):

xia-chao requested wasmtime-wasi-reviewers for a review on PR #14397.

Last updated: Oct 11 2026 at 04:10 UTC