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From: Jim Mattson <jmattson@google.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Jim Mattson <jmattson@google.com>, Jue Wang <juew@google.com>,
	Peter Shier <pshier@google.com>
Subject: [PATCH] KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mce
Date: Mon, 11 May 2020 15:56:16 -0700	[thread overview]
Message-ID: <20200511225616.19557-1-jmattson@google.com> (raw)

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>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d786c7d27ce5..5bf45c9aa8e5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3751,7 +3751,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
 	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;
-- 
2.26.2.645.ge9eca65c58-goog


             reply	other threads:[~2020-05-11 22:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-11 22:56 Jim Mattson [this message]
2020-05-14 17:46 ` [PATCH] KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mce Jim Mattson
2020-05-15 12:36 ` Vitaly Kuznetsov
2020-05-15 17:49 ` Paolo Bonzini

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