hypervisor: kvm: aarch64: fix get_device_attr() UB#6647
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liuw merged 1 commit intocloud-hypervisor:mainfrom Aug 13, 2024
Merged
hypervisor: kvm: aarch64: fix get_device_attr() UB#6647liuw merged 1 commit intocloud-hypervisor:mainfrom
liuw merged 1 commit intocloud-hypervisor:mainfrom
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DeviceFd::get_device_attr should be marked as unsafe, because it allows writing to an arbitrary address. I have opened a kvm-ioctls PR[1] to fix this. The hypervisor crate was using the function unsafely by passing it addresses of immutable variables. I noticed this because an optimisation change[2] in Rust 1.80.0 caused the kvm::aarch64::gic::tests::test_get_set_icc_regs test to start failing when built in release mode. To fix this, I've broken up the _access functions into _set and _get variants, with the _get variant using a pointer to a mutable variable. This has the side effect of making these functions a bit nicer to use, because the caller now has no need to use references at all, for either getting or setting. [1]: rust-vmm/kvm#273 [2]: rust-lang/rust@d2d24e3 Signed-off-by: Alyssa Ross <hi@alyssa.is>
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likebreath
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liuw
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rbradford
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Presumably test_vfio is just flaky, given it failed on x86_64 and this code only touched aarch64-specific code? |
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Last time it failed on musl, and worked on GNU, and this time it's the opposite… |
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DeviceFd::get_device_attrshould be marked as unsafe, because it allows writing to an arbitrary address. I have opened a kvm-ioctls PR to fix this. The hypervisor crate was using the function unsafely by passing it addresses of immutable variables. I noticed this because an optimisation change in Rust 1.80.0 caused thekvm::aarch64::gic::tests::test_get_set_icc_regstest to start failing when built in release mode.To fix this, I've broken up the _access functions into _set and _get variants, with the _get variant using a pointer to a mutable variable. This has the side effect of making these functions a bit nicer to use, because the caller now has no need to use references at all, for either getting or setting.