Don't lie about buffer initialization #47
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Darksonn
reviewed
Dec 5, 2023
src/lib.rs
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| // SAFETY: read_uninit does not de-initialize the buffer and guarantees that the first nread | ||
| // bytes are initialized. | ||
| self.with_context(ctx, |s| unsafe { | ||
| match cvt(s.read_uninit(buf.unfilled_mut()))? { | ||
| Poll::Ready(nread) => { | ||
| unsafe { | ||
| buf.assume_init(nread); | ||
| } | ||
| buf.assume_init(nread); | ||
| buf.advance(nread); | ||
| Poll::Ready(Ok(())) |
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Generally you should avoid so large unsafe blocks.
// SAFETY: The `read_uninit` method promises to never deinitialize any of the bytes.
match cvt(s.read_uninit(unsafe { buf.unfilled_mut() }))? {
Poll::Ready(nread) => {
// SAFETY: The `read_uninit` method promises that the first `nread` bytes of the buffer are now initialized.
unsafe { buf.assume_init(nread) };There was a problem hiding this comment.
Updated! Sorry for the delay.
Darksonn
approved these changes
Dec 9, 2023
src/lib.rs
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Comment on lines
235
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237
| unsafe { | ||
| buf.assume_init(nread); | ||
| } |
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Nit: If you move the semicolon outside the unsafe block, then rustfmt formats this on one line.
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It's formally UB to create a
&mut [u8]out of possibly-uninitialized bytes. Instead, use the newopensslAPIs that work directly with&mut [MaybeUninit<u8>].Closes #46