GHSA-rwq6-crjg-9cpw ic-cdk has a memory leak when calling a canister method via `ic_cdk::call`

• crates.io ic_cdk: >= 0.8.0, < 0.8.2 → fixed in 0.8.2 • crates.io ic_cdk: >= 0.9.0, < 0.9.3 → fixed in 0.9.3 • crates.io ic_cdk: >= 0.10.0, < 0.10.1 → fixed in 0.10.1 • crates.io ic_cdk: >= 0.11.0, < 0.11.6 → fixed in 0.11.6 • crates.io ic_cdk: >= 0.12.0, < 0.12.2 → fixed in 0.12.2 • crates.io ic_cdk: >= 0.13.0, < 0.13.5 → fixed in 0.13.5 • crates.io ic_cdk: >= 0.14.0, < 0.14.1 → fixed in 0.14.1 • crates.io ic_cdk: >= 0.15.0, < 0.15.1 → fixed in 0.15.1

When a canister method is called via `ic_cdk::call*`, a new Future `CallFuture` is created and can be awaited by the caller to get the execution result. Internally, the state of the Future is tracked and stored in a struct called `CallFutureState`. A bug in the polling implementation of the `CallFuture` allows multiple references to be held for this internal state and not all references were dropped before the `Future` is resolved. Since we have unaccounted references held, a copy of the internal state ended up being persisted in the canister's heap and thus causing a memory leak. Impact Canisters built in Rust with `ic_cdk` and `ic_cdk_timers` are affected. If these canisters call a canister method, use timers or heartbeat, they will likely leak a small amount of memory on every such operation. In the worst case, this could lead to heap memory exhaustion triggered by an attacker. Motoko based canisters are not affected by the bug. Patches The patch has been backported to all minor versions between `>= 0.8.0, [!NOTE] > Upgrading the canisters (without updating `ic_cdk`) also frees the leaked memory but it's only a temporary solution. References • dfinity/cdk-rs/pull/509 • ic_cdk docs • Internet Computer Specification