fix(cordyceps): pin list::IterMut items
#209
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Currently, there is a potential safety issue when using `cordyceps::list::IterMut`: the iterator's item type is `&mut T`. `&mut T`s may be `mem::replace`d or `mem::take`en, moving them out of the list to a different memory location. This would invalidate any pointers in the list that point to that node. Therefore, to ensure that the mutable iterator cannot corrupt the list (potentially leading to dangling pointers or use-after-frees), this PR changes `list::IterMut`'s `Item` type from `&'list mut T` to `Pin<&'list mut T`. This ensures that the iterator cannot be used to corrupt the list.
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No objections from me. It might make sense to do a sit-down review together at some point, and figure out all the ownership/iteration requirements for List? it seems like there's been a couple of conceptual issues that have popped up, it might make sense to make the high level docs/reqs more clear so it's easier to review on this. |
hawkw
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Jun 23, 2022
Currently, the `Item` type of `list::CursorMut`'s `Iterator` impl is `&mut T`. This is incorrect, as it allows the items to be moved out of the list without unlinking them. Instead, the iterator's item type must be `Pin`ned. PR #209 made this change for the `IterMut` type, but did not make the same change for `CursorMut`, so this commit fixes `CursorMut` similarly. BREAKING CHANGE: This changes the type signature of the `Iterator` impl for `list::CursorMut`.
hawkw
added a commit
that referenced
this pull request
Jun 23, 2022
Currently, the `Item` type of `list::CursorMut`'s `Iterator` impl is `&mut T`. This is incorrect, as it allows the items to be moved out of the list without unlinking them. Instead, the iterator's item type must be `Pin`ned. PR #209 made this change for the `IterMut` type, but did not make the same change for `CursorMut`, so this commit fixes `CursorMut` similarly. BREAKING CHANGE: This changes the type signature of the `Iterator` impl for `list::CursorMut`.
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Currently, there is a potential safety issue when using
cordyceps::list::IterMut: the iterator's item type is&mut T.&mut Ts may bemem::replaced ormem::takeen, moving them out ofthe list to a different memory location. This would invalidate any
pointers in the list that point to that node.
Therefore, to ensure that the mutable iterator cannot corrupt the list
(potentially leading to dangling pointers or use-after-frees), this PR
changes
list::IterMut'sItemtype from&'list mut TtoPin<&'list mut T. This ensures that the iterator cannot be used tocorrupt the list.