Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 24/34] arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE | Date | Wed, 1 Jul 2015 11:40:31 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Christoffer Dall <christoffer.dall@linaro.org>
commit c3058d5da2222629bc2223c488a4512b59bb4baf upstream.
[Since we don't backport commit 8eef912 (arm/arm64: KVM: map MMIO regions at creation time) for linux-3.14.y, the context of this patch is different, while the change itself is same.]
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> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/arm/kvm/mmu.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -926,6 +926,9 @@ int kvm_handle_guest_abort(struct kvm_vc memslot = gfn_to_memslot(vcpu->kvm, gfn); + /* 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, fault_status); if (ret == 0) ret = 1; @@ -1150,6 +1153,14 @@ int kvm_arch_prepare_memory_region(struc struct kvm_userspace_memory_region *mem, enum kvm_mr_change change) { + /* + * 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; + return 0; }
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