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From:   Philipp Stanner <pstanner@redhat.com>
To:     Christian Borntraeger <borntraeger@linux.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        David Hildenbrand <david@redhat.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>
Cc:     kvm@vger.kernel.org, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        Philipp Stanner <pstanner@redhat.com>,
        Dave Airlie <airlied@redhat.com>
Subject: [PATCH 1/3] arch/x86/kvm: copy user-array with overflow-check
Date:   Thu,  2 Nov 2023 19:15:24 +0100
Message-ID: <20231102181526.43279-2-pstanner@redhat.com>
In-Reply-To: <20231102181526.43279-1-pstanner@redhat.com>
References: <20231102181526.43279-1-pstanner@redhat.com>
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cpuid.c utilizes vmemdup_user() and array_size() to copy two userspace
arrays. This, currently, does not check for an overflow.

Use the new wrapper vmemdup_array_user() to copy the arrays more safely.

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
 arch/x86/kvm/cpuid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 773132c3bf5a..4a15b2a20f84 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -467,7 +467,7 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 		return -E2BIG;
 
 	if (cpuid->nent) {
-		e = vmemdup_user(entries, array_size(sizeof(*e), cpuid->nent));
+		e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e));
 		if (IS_ERR(e))
 			return PTR_ERR(e);
 
@@ -511,7 +511,7 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
 		return -E2BIG;
 
 	if (cpuid->nent) {
-		e2 = vmemdup_user(entries, array_size(sizeof(*e2), cpuid->nent));
+		e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2));
 		if (IS_ERR(e2))
 			return PTR_ERR(e2);
 	}
-- 
2.41.0