Affected versions of oneringbuf exposed the obsolete IntoRef::into_ref method through the public IntoRef trait. For heap-backed ring buffers, this method returned a DroppableRef handle.
DroppableRef stored an owning raw pointer created from Box::into_raw. Its Clone implementation copied this raw pointer without incrementing the internal alive_iters counter. Internally, this clone pattern appears to rely on a fixed number of handles being created to match the initial alive_iters value. However, exposing DroppableRef through the public IntoRef::TargetRef associated type allows safe external code to create additional clones beyond that fixed count, breaking the lifetime protocol. Drop later dereferenced the pointer and could free the backing allocation with Box::from_raw.
Safe code could call IntoRef::into_ref to obtain a DroppableRef and then clone it. Each clone pointed to the same allocation, but the internal alive_iters counter was not increased. As a result, one clone could free the allocation while another clone still existed. Dropping the remaining clone then accessed freed memory, causing a heap-use-after-free.
The issue was fixed in version 0.8.0 by removing the obsolete into_ref method.
Trigger
use oneringbuf::{IntoRef, LocalHeapRB};
fn main() {
let rb = LocalHeapRB::<usize>::from(vec![1, 2, 3]);
let r = <LocalHeapRB<usize> as IntoRef>::into_ref(rb);
let r2 = r.clone();
let r3 = r.clone();
drop(r);
drop(r2);
drop(r3); // AddressSanitizer: heap-use-after-free
}
References
Affected versions of
oneringbufexposed the obsoleteIntoRef::into_refmethod through the publicIntoReftrait. For heap-backed ring buffers, this method returned aDroppableRefhandle.DroppableRefstored an owning raw pointer created fromBox::into_raw. ItsCloneimplementation copied this raw pointer without incrementing the internalalive_iterscounter. Internally, this clone pattern appears to rely on a fixed number of handles being created to match the initialalive_itersvalue. However, exposingDroppableRefthrough the publicIntoRef::TargetRefassociated type allows safe external code to create additional clones beyond that fixed count, breaking the lifetime protocol.Droplater dereferenced the pointer and could free the backing allocation withBox::from_raw.Safe code could call
IntoRef::into_refto obtain aDroppableRefand then clone it. Each clone pointed to the same allocation, but the internalalive_iterscounter was not increased. As a result, one clone could free the allocation while another clone still existed. Dropping the remaining clone then accessed freed memory, causing a heap-use-after-free.The issue was fixed in version 0.8.0 by removing the obsolete
into_refmethod.Trigger
References