[3.16.y-ckt stable] Patch "arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Wed May 20 12:30:26 UTC 2015
This is a note to let you know that I have just added a patch titled
arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt12.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From ca2d284cf1b71ffe8e633af14355d2868612e6a1 Mon Sep 17 00:00:00 2001
From: Christoffer Dall <christoffer.dall at linaro.org>
Date: Fri, 10 Oct 2014 12:14:29 +0200
Subject: arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE
commit c3058d5da2222629bc2223c488a4512b59bb4baf upstream.
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 at arm.com>
Acked-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
[ luis: backported to 3.16: used shannon's backport for 3.14 ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
arch/arm/kvm/mmu.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 0258b22bf9d1..2555a52cccd2 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -926,6 +926,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
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(struct kvm *kvm,
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;
}
More information about the kernel-team
mailing list