Commit c4e0e4ab authored by Jim Mattson's avatar Jim Mattson Committed by Paolo Bonzini

KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mce

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: a9e38c3e ("KVM: x86: Catch potential overrun in MCE setup")
Signed-off-by: default avatarJue Wang <juew@google.com>
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Reviewed-by: default avatarPeter Shier <pshier@google.com>
Message-Id: <20200511225616.19557-1-jmattson@google.com>
Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f6bfd9c8
...@@ -3759,7 +3759,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu, ...@@ -3759,7 +3759,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
unsigned bank_num = mcg_cap & 0xff, bank; unsigned bank_num = mcg_cap & 0xff, bank;
r = -EINVAL; r = -EINVAL;
if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS) if (!bank_num || bank_num > KVM_MAX_MCE_BANKS)
goto out; goto out;
if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000)) if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000))
goto out; goto out;
......
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