[PATCH v2 0/2] KVM: fixes for the kernel-hardening tree

From: Paolo Bonzini
Date: Thu Oct 26 2017 - 09:45:59 EST


Four KVM ioctls (KVM_GET/SET_CPUID2 on x86, KVM_GET/SET_ONE_REG on
ARM and s390) directly access the kvm_vcpu_arch struct. Therefore, the
new usercopy hardening work in linux-next, which forbids copies from and
to slab objects unless they are from kmalloc or explicitly whitelisted,
breaks KVM on those architectures.

The kvm_vcpu_arch struct is embedded in the kvm_vcpu struct and the
corresponding slab cache is allocated by architecture-independent code.
It is enough, for simplicity, to whitelist the whole sub-struct and
only touch one place of the KVM code. Later, any further restrictions
can be applied in the KVM tree.

Paolo Bonzini (2):
kvm: whitelist struct kvm_vcpu_arch
kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl

arch/x86/kvm/x86.c | 7 ++++---
virt/kvm/kvm_main.c | 8 ++++++--
2 files changed, 10 insertions(+), 5 deletions(-)

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2.14.2