On 11.12.19 21:47, Marios Pomonis wrote:
This fixes Spectre-v1/L1TF vulnerabilities in kvm_hv_msr_get_crash_data() and kvm_hv_msr_set_crash_data(). These functions contain index computations that use the (attacker-controlled) MSR number.
Fixes: commit e7d9513b60e8 ("kvm/x86: added hyper-v crash msrs into kvm hyperv context")
Signed-off-by: Nick Finco nifi@google.com Signed-off-by: Marios Pomonis pomonis@google.com Reviewed-by: Andrew Honig ahonig@google.com Cc: stable@vger.kernel.org
arch/x86/kvm/hyperv.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 23ff65504d7e..26408434b9bc 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -809,11 +809,12 @@ static int kvm_hv_msr_get_crash_data(struct kvm_vcpu *vcpu, u32 index, u64 *pdata) { struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
- size_t size = ARRAY_SIZE(hv->hv_crash_param);
- if (WARN_ON_ONCE(index >= ARRAY_SIZE(hv->hv_crash_param)))
- if (WARN_ON_ONCE(index >= size)) return -EINVAL;
The fact that we do a WARN_ON_ONCE here, should actually tell that index is not user controllable. Otherwise this would indicate the possibility to trigger a kernel warning from a malicious user space. So a: we do not need this change or b: we must also fix the WARN_ON_ONCE