From: Jim Mattson jmattson@google.com
commit c4e0e4ab4cf3ec2b3f0b628ead108d677644ebd9 upstream.
Bank_num is a one-based count of banks, not a zero-based index. It overflows the allocated space only when strictly greater than KVM_MAX_MCE_BANKS.
Fixes: a9e38c3e01ad ("KVM: x86: Catch potential overrun in MCE setup") Signed-off-by: Jue Wang juew@google.com Signed-off-by: Jim Mattson jmattson@google.com Reviewed-by: Peter Shier pshier@google.com Message-Id: 20200511225616.19557-1-jmattson@google.com Reviewed-by: Vitaly Kuznetsov vkuznets@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3739,7 +3739,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce( unsigned bank_num = mcg_cap & 0xff, bank;
r = -EINVAL; - if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS) + if (!bank_num || bank_num > KVM_MAX_MCE_BANKS) goto out; if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000)) goto out;