linked_list_allocator vulnerable to out-of-bound writes on `Heap` initialization and `Heap::extend`

Summary

linked_list_allocator is an allocator usable for no_std systems. Prior to version 0.10.2, the heap initialization methods were missing a minimum size check for the given heap size argument. This could lead to out-of-bound writes when a heap was initialized with a size smaller than `3 * size_of::<usize>` because of metadata write operations. This vulnerability impacts all the initialization functions on the `Heap` and `LockedHeap` types, including `Heap::new`, `Heap::init`, `Heap::init_from_slice`, and `LockedHeap::new`. It also affects multiple uses of the `Heap::extend` method. Version 0.10.2 contains a patch for the issue. As a workaround, ensure that the heap is only initialized with a size larger than `3 * size_of::<usize>` and that the `Heap::extend` method is only called with sizes larger than `2 * size_of::<usize>()`. Also, ensure that the total heap size is (and stays) a multiple of `2 * size_of::<usize>()`.

Timeline

1. Sep 7, 2022, 10:50 PM UTCCVE published
2. Apr 22, 2025, 3:42 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: total

3. Apr 22, 2025, 5:23 PM UTCRecord last updated

Affected versions

• rust-osdev linked-list-allocator

  fixed in 0.10.2

• linked_list_allocatorcrates.io

  fixed in 0.10.2

• linked_list_allocatorcrates.io

  From 0.0.0-0 · fixed in 0.10.2

References 2