4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jim Mattson <[email protected]> commit 85c856b39b479dde410ddd09df1da745343010c9 upstream 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 <[email protected]> Message-Id: <[email protected]> [Change 1UL to 1, to match the range check on the shift count. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]> [jwang: port from linux-4.9 to 4.4 ] Signed-off-by: Jack Wang <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kvm/vmx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7361,7 +7361,7 @@ static int handle_invept(struct kvm_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); @@ -7420,7 +7420,7 @@ static int handle_invvpid(struct kvm_vcp 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);
