Fix multiple soundness issues #103
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DemiMarie
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jinankjain,
likebreath,
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vfio_syscall::map_dma causes the kernel to make an arbitrary address accessible for DMA by a device the guest typically controls. This is unsafe, as it can change memory that Rust assumes is immutable. I found this through a review of Cloud Hypervisor [1], where I saw a safe function that took a host address cast to u64 as an argument and accessed that address. It turns out that this function was the source of the unsoundness. [1]: cloud-hypervisor/cloud-hypervisor#7129 Signed-off-by: Demi Marie Obenour <[email protected]>
GuestMemory is a safe trait, so it is permissible for GuestMemory::get_host_address() to return a garbage pointer that is obviously unsafe to use. Instead, use GuestMemory::get_slice(), which returns a VolatileSlice that always points to valid memory. See rust-vmm/vm-memory#332 for details. Signed-off-by: Demi Marie Obenour <[email protected]>
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Summary of the PR
vfio_syscall::map_dma causes the kernel to make an arbitrary address
accessible for DMA by a device the guest typically controls. This is
unsafe, as it can change memory that Rust assumes is immutable.
I found this through a review of Cloud Hypervisor, where I saw a
safe function that took a host address cast to u64 as an argument and
accessed that address. It turns out that this function was the source
of the unsoundness.
Requirements
Before submitting your PR, please make sure you addressed the following
requirements:
git commit -s), and the commit message has max 60 characters for thesummary and max 75 characters for each description line.
test.
Release" section of CHANGELOG.md (if no such section exists, please create one).
unsafecode is properly documented.