Commit c3058d5d authored by Christoffer Dall's avatar Christoffer Dall

arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE

When creating or moving a memslot, make sure the IPA space is within the
addressable range of the guest.  Otherwise, user space can create too
large a memslot and KVM would try to access potentially unallocated page
table entries when inserting entries in the Stage-2 page tables.
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 38f791a4
...@@ -1003,6 +1003,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) ...@@ -1003,6 +1003,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
goto out_unlock; goto out_unlock;
} }
/* Userspace should not be able to register out-of-bounds IPAs */
VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);
ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status); ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);
if (ret == 0) if (ret == 0)
ret = 1; ret = 1;
...@@ -1228,6 +1231,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, ...@@ -1228,6 +1231,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
if (change != KVM_MR_CREATE && change != KVM_MR_MOVE) if (change != KVM_MR_CREATE && change != KVM_MR_MOVE)
return 0; return 0;
/*
* Prevent userspace from creating a memory region outside of the IPA
* space addressable by the KVM guest IPA space.
*/
if (memslot->base_gfn + memslot->npages >=
(KVM_PHYS_SIZE >> PAGE_SHIFT))
return -EFAULT;
/* /*
* A memory region could potentially cover multiple VMAs, and any holes * A memory region could potentially cover multiple VMAs, and any holes
* between them, so iterate over all of them to find out if we can map * between them, so iterate over all of them to find out if we can map
......
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