This is a note to let you know that I've just added the patch titled
KVM: x86: fix wbinvd_dirty_mask use-after-free
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-fix-wbinvd_dirty_mask-use-after-free.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bd768e146624cbec7122ed15dead8daa137d909d Mon Sep 17 00:00:00 2001
From: Ido Yariv <ido@xxxxxxxxxx>
Date: Fri, 21 Oct 2016 12:39:57 -0400
Subject: KVM: x86: fix wbinvd_dirty_mask use-after-free
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From: Ido Yariv <ido@xxxxxxxxxx>
commit bd768e146624cbec7122ed15dead8daa137d909d upstream.
vcpu->arch.wbinvd_dirty_mask may still be used after freeing it,
corrupting memory. For example, the following call trace may set a bit
in an already freed cpu mask:
kvm_arch_vcpu_load
vcpu_load
vmx_free_vcpu_nested
vmx_free_vcpu
kvm_arch_vcpu_free
Fix this by deferring freeing of wbinvd_dirty_mask.
Signed-off-by: Ido Yariv <ido@xxxxxxxxxx>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7252,10 +7252,12 @@ void kvm_put_guest_fpu(struct kvm_vcpu *
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
+ void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask;
+
kvmclock_reset(vcpu);
- free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
kvm_x86_ops->vcpu_free(vcpu);
+ free_cpumask_var(wbinvd_dirty_mask);
}
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
Patches currently in stable-queue which might be from ido@xxxxxxxxxx are
queue-4.4/kvm-x86-fix-wbinvd_dirty_mask-use-after-free.patch
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