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Fix Reference Count Overflow (Use-After-Free) in Atom::clone #301

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Merged
SimonSapin merged 1 commit into from
Aug 19, 2026
+5 −1
Merged

Fix Reference Count Overflow (Use-After-Free) in Atom::clone #301

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6 changes: 5 additions & 1 deletion src/atom.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -248,7 +248,11 @@
fn clone(&self) -> Self {
if self.tag() == DYNAMIC_TAG {
let entry = self.unsafe_data.get() as *const Entry;
unsafe { &*entry }.ref_count.fetch_add(1, SeqCst);
// SAFETY: `self` is a valid Atom, meaning its `unsafe_data` points to a live `Entry`
// kept alive by `self`'s reference count. We can safely dereference it.
if unsafe { &*entry }.ref_count.fetch_add(1, SeqCst) == std::isize::MAX {

Check failure on line 253 in src/atom.rs

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use of deprecated constant `std::isize::MAX`: replaced by the `MAX` associated constant on this type

Check warning on line 253 in src/atom.rs

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use of deprecated constant `std::isize::MAX`: replaced by the `MAX` associated constant on this type
std::process::abort();
}
}
Atom { ..*self }
}
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