[PATCH openEuler-1.0-LTS 1/2] KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656)
From: Maxim Levitsky mlevitsk@redhat.com
stable inclusion from linux-4.19.205 commit 119d547cbf7c055ba8100309ad71910478092f24 CVE: CVE-2021-3656
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[ upstream commit c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc ]
If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor), then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only possible by making L0 intercept these instructions.
Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted, and thus read/write portions of the host physical memory.
Fixes: 89c8a4984fc9 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature")
Suggested-by: Paolo Bonzini pbonzini@redhat.com 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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/x86/kvm/svm.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 464e271dc354d..1076dc1bd92ae 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -513,6 +513,9 @@ static void recalc_intercepts(struct vcpu_svm *svm) c->intercept_dr = h->intercept_dr | g->intercept_dr; c->intercept_exceptions = h->intercept_exceptions | g->intercept_exceptions; c->intercept = h->intercept | g->intercept; + + c->intercept |= (1ULL << INTERCEPT_VMLOAD); + c->intercept |= (1ULL << INTERCEPT_VMSAVE); }
static inline struct vmcb *get_host_vmcb(struct vcpu_svm *svm)
From: Maxim Levitsky mlevitsk@redhat.com
stable inclusion from linux-4.19.205 commit 42f4312c0e8a225b5f1e3ed029509ef514f2157a CVE: CVE-2021-3653
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[ 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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/x86/include/asm/svm.h | 2 ++ arch/x86/kvm/svm.c | 15 ++++++++------- 2 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index 93b462e480671..b6dedf6c835c9 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -118,6 +118,8 @@ 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 1076dc1bd92ae..236e94d56722c 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1396,12 +1396,7 @@ static __init int svm_hardware_setup(void) } }
- if (vgif) { - if (!boot_cpu_has(X86_FEATURE_VGIF)) - vgif = false; - else - pr_info("Virtual GIF supported\n"); - } + vgif = false; /* Disabled for CVE-2021-3653 */
return 0;
@@ -3531,7 +3526,13 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, svm->nested.intercept = nested_vmcb->control.intercept;
svm_flush_tlb(&svm->vcpu, true); - svm->vmcb->control.int_ctl = nested_vmcb->control.int_ctl | V_INTR_MASKING_MASK; + + svm->vmcb->control.int_ctl &= + V_INTR_MASKING_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK; + + svm->vmcb->control.int_ctl |= nested_vmcb->control.int_ctl & + (V_TPR_MASK | V_IRQ_INJECTION_BITS_MASK); + if (nested_vmcb->control.int_ctl & V_INTR_MASKING_MASK) svm->vcpu.arch.hflags |= HF_VINTR_MASK; else
-
Yang Yingliang