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util: Zero-initialize result to prevent possible uninit memory read #470

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Aug 23, 2021
Merged

util: Zero-initialize result to prevent possible uninit memory read #470

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4 changes: 4 additions & 0 deletions Changelog.md
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

## [Unreleased] - ReleaseDate

### Fixed

- util: Zero-initialize result to prevent possible uninit memory read (#470)

## [0.33.0] - 2021-07-30

### Added
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13 changes: 5 additions & 8 deletions ash/src/util.rs
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Expand Up @@ -113,15 +113,12 @@ pub fn read_spv<R: io::Read + io::Seek>(x: &mut R) -> io::Result<Vec<u32>> {
return Err(io::Error::new(io::ErrorKind::InvalidData, "input too long"));
}
let words = (size / 4) as usize;
let mut result = Vec::<u32>::with_capacity(words);
// https://github.com/MaikKlein/ash/issues/354:
// Zero-initialize the result to prevent read_exact from possibly
// reading uninitialized memory.
let mut result = vec![0u32; words];
x.seek(io::SeekFrom::Start(0))?;
unsafe {
x.read_exact(slice::from_raw_parts_mut(
result.as_mut_ptr() as *mut u8,
words * 4,
))?;
result.set_len(words);
}
x.read_exact(unsafe { slice::from_raw_parts_mut(result.as_mut_ptr() as *mut u8, words * 4) })?;
const MAGIC_NUMBER: u32 = 0x0723_0203;
if !result.is_empty() && result[0] == MAGIC_NUMBER.swap_bytes() {
for word in &mut result {
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