From 4307c685579bf511b458e7ec3e0be902d0d93c9c Mon Sep 17 00:00:00 2001
From: Lukas Markeffsky <@>
Date: Thu, 1 Feb 2024 10:21:09 +0000
Subject: [PATCH] fix soundness
---
src/lib.rs | 38 ++++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/src/lib.rs b/src/lib.rs
index 16b985a..5ec943a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,7 +19,7 @@ unsafe fn reclaim_shim<T: Reclaim>(erased_ptr: NonNull<Root<Erased>>) {
(*ptr.as_ptr()).state.set(STATE_UNCLAIMED);
};
- let value = unsafe { (*ptr.as_ptr()).target.assume_init_read().value };
+ let value = unsafe { ptr::addr_of!((*(*ptr.as_ptr()).target.as_ptr()).value).read() };
let unclaimed = Unclaimed { ptr };
value.reclaim(unclaimed);
@@ -48,7 +48,7 @@ pub struct Root<T> {
impl<T> Drop for Root<T> {
fn drop(&mut self) {
let state = self.state.get();
- if state <= STATE_SHARED_MAX {
+ if state != STATE_UNPINNED {
struct Abort;
impl Drop for Abort {
fn drop(&mut self) {
@@ -132,6 +132,15 @@ pub struct Unclaimed<T> {
ptr: NonNull<Root<T>>,
}
+impl<T> Drop for Unclaimed<T> {
+ fn drop(&mut self) {
+ unsafe {
+ debug_assert_eq!((*self.ptr.as_ptr()).state.get(), STATE_UNCLAIMED);
+ (*self.ptr.as_ptr()).state.set(STATE_UNPINNED);
+ }
+ }
+}
+
impl<T> Unclaimed<T> {
pub fn claim(self, value: T) -> Xrc<T> {
unsafe {
@@ -147,6 +156,7 @@ impl<T> Unclaimed<T> {
// shared read-only reborrow
let target = unsafe { (*self.ptr.as_ptr()).target.assume_init_ref() };
let ptr = NonNull::from(target);
+ mem::forget(self);
Xrc { ptr }
}
}
@@ -280,7 +290,16 @@ mod tests {
#[test]
#[ignore = "will abort"]
- fn abort() {
+ fn abort_unclaimed() {
+ #[allow(clippy::needless_late_init)]
+ let _unclaimed;
+ let root = pin!(Root::<NoReclaim<()>>::new());
+ _unclaimed = root.unclaimed();
+ }
+
+ #[test]
+ #[ignore = "will abort"]
+ fn abort_xrc() {
#[allow(clippy::needless_late_init)]
let _xrc;
let root = pin!(Root::new());
@@ -288,10 +307,17 @@ mod tests {
}
#[test]
- #[should_panic = "unclaimed called multiple times"]
- fn multiple_unclaimed() {
- let mut root = pin!(Root::<NoReclaim<i32>>::new());
+ fn multiple_unclaimed_separate() {
+ let mut root = pin!(Root::<NoReclaim<()>>::new());
+ let _ = root.as_mut().unclaimed();
let _ = root.as_mut().unclaimed();
+ }
+
+ #[test]
+ #[should_panic = "unclaimed called multiple times"]
+ fn multiple_unclaimed_concurrent() {
+ let mut root = pin!(Root::<NoReclaim<()>>::new());
+ let _unclaimed = root.as_mut().unclaimed();
let _ = root.as_mut().unclaimed();
}
--
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