CVE-2023-41051: fix: Validate return value of get_slice in VolatileMemory · rust-vmm/vm-memory@aff1dd4

In a typical Virtual Machine Monitor (VMM) there are several components, such as boot loader, virtual device drivers, virtio backend drivers and vhost drivers, that need to access the VM physical memory. The vm-memory rust crate provides a set of traits to decouple VM memory consumers from VM memory providers. An issue was discovered in the default implementations of the VolatileMemory::{get_atomic_ref, aligned_as_ref, aligned_as_mut, get_ref, get_array_ref} trait functions, which allows out-of-bounds memory access if the VolatileMemory::get_slice function returns a VolatileSlice whose length is less than the function’s count argument. No implementations of get_slice provided in vm_memory are affected. Users of custom VolatileMemory implementations may be impacted if the custom implementation does not adhere to get_slice's documentation. The issue started in version 0.1.0 but was fixed in version 0.12.2 by inserting a check that verifies that the VolatileSlice returned by get_slice is of the correct length. Users are advised to upgrade. There are no known workarounds for this issue.