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authorChristoffer Dall <christoffer.dall@linaro.org>2014-10-10 12:14:29 +0200
committerChristoffer Dall <christoffer.dall@linaro.org>2014-10-14 05:48:25 -0700
commitc3058d5da2222629bc2223c488a4512b59bb4baf (patch)
treec34f1e9fcf3909ddd493f644902b29ca18168236
parent38f791a4e499792eeb2a3c0572dd5133511c5bbb (diff)
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: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
-rw-r--r--arch/arm/kvm/mmu.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index ee142edcca84..8c40829d4a52 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1003,6 +1003,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
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);
if (ret == 0)
ret = 1;
@@ -1229,6 +1232,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
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
* between them, so iterate over all of them to find out if we can map
* any of them right now.

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