diff options
| author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-08-16 16:02:31 +0200 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2021-08-26 08:37:48 -0400 |
| commit | 53723b7be26ef31ad642ce5ffa8b42dec16db40e (patch) | |
| tree | f02e345797b7ac571d2b1ae153cffeb52cfeb934 /arch | |
| parent | f1c2379db980d52f181d30321b2eb395e3a91858 (diff) | |
KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653)
[ upstream commit 0f923e07124df069ba68d8bb12324398f4b6b709 ]
* Invert the mask of bits that we pick from L2 in
nested_vmcb02_prepare_control
* Invert and explicitly use VIRQ related bits bitmask in svm_clear_vintr
This fixes a security issue that allowed a malicious L1 to run L2 with
AVIC enabled, which allowed the L2 to exploit the uninitialized and enabled
AVIC to read/write the host physical memory at some offsets.
Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/svm.h | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/svm.c | 6 |
2 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index 6136d99f537b..c1adb2ed6d41 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -108,6 +108,8 @@ struct __attribute__ ((__packed__)) vmcb_control_area { #define V_IGN_TPR_SHIFT 20 #define V_IGN_TPR_MASK (1 << V_IGN_TPR_SHIFT) +#define V_IRQ_INJECTION_BITS_MASK (V_IRQ_MASK | V_INTR_PRIO_MASK | V_IGN_TPR_MASK) + #define V_INTR_MASKING_SHIFT 24 #define V_INTR_MASKING_MASK (1 << V_INTR_MASKING_SHIFT) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 931acac69703..77bee73faebc 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2564,7 +2564,11 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm) svm->nested.intercept = nested_vmcb->control.intercept; svm_flush_tlb(&svm->vcpu); - svm->vmcb->control.int_ctl = nested_vmcb->control.int_ctl | V_INTR_MASKING_MASK; + svm->vmcb->control.int_ctl = nested_vmcb->control.int_ctl & + (V_TPR_MASK | V_IRQ_INJECTION_BITS_MASK); + + svm->vmcb->control.int_ctl |= V_INTR_MASKING_MASK; + if (nested_vmcb->control.int_ctl & V_INTR_MASKING_MASK) svm->vcpu.arch.hflags |= HF_VINTR_MASK; else |