kvm: nVMX: Fix kernel panics induced by illegal INVEPT/INVVPID types (85c856b3) · Commits · 戴 / test

Bitwise shifts by amounts greater than or equal to the width of the left operand are undefined. A malicious guest can exploit this to crash a 32-bit host, due to the BUG_ON(1)'s in handle_{invept,invvpid}. Signed-off-by:

Jim Mattson <jmattson@google.com> Message-Id: <1477496318-17681-1-git-send-email-jmattson@google.com> [Change 1UL to 1, to match the range check on the shift count. - Paolo] Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -7659,7 +7659,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)

		types = (vmx->nested.nested_vmx_ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;

		if (!(types & (1UL << type))) {
		if (type >= 32 \|\| !(types & (1 << type))) {
		nested_vmx_failValid(vcpu,
		VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
		skip_emulated_instruction(vcpu);
		@@ -7722,7 +7722,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)

		types = (vmx->nested.nested_vmx_vpid_caps >> 8) & 0x7;

		if (!(types & (1UL << type))) {
		if (type >= 32 \|\| !(types & (1 << type))) {
		nested_vmx_failValid(vcpu,
		VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
		skip_emulated_instruction(vcpu);

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